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Orange juice

Orange juice is a liquid extract of the orange tree fruit, produced by squeezing or reaming oranges. It comes in several different varieties, including blood orange, navel oranges, valencia orange, clementine, and tangerine. As well as variations in oranges used, some varieties include differing amounts of juice vesicles, known as "pulp" in American English, and "(juicy) bits" in British English. These vesicles contain the juice of the orange and can be left in or removed during the manufacturing process. How juicy these vesicles are depend upon many factors, such as species, variety, and season. In American English, the beverage name is often abbreviated as "OJ".

Commercial orange juice with a long shelf life is made by pasteurizing the juice and removing the oxygen from it. This removes much of the taste, necessitating the later addition of a flavor pack, generally made from orange products. Additionally, some juice is further processed by drying and later rehydrating the juice, or by concentrating the juice and later adding water to the concentrate.

The health value of orange juice is debatable: it has a high concentration of vitamin C, but also a very high concentration of simple sugars, comparable to soft drinks. As a result, some government nutritional advice has been adjusted to encourage substitution of orange juice with raw fruit, which is digested more slowly, and limit daily consumption.

History
During World War II, American soldiers rejected vitamin C-packed lemon crystals because of their unappetizing taste. Thus the US government searched for a food that would fulfill the nutritional needs of the soldiers, have a desirable taste, and prevent diseases such as scurvy. The US federal government and the Florida Department of Citrus worked with a group of scientists to develop a product superior to the canned orange juice available in the 1940s. The result was frozen concentrated orange juice; this was not until three years after the war had ended.

By 1949, orange juice processing plants in Florida were producing over 10 million gallons of concentrated orange juice. Consumers liked concentrated canned orange juice as it was affordable, tasty, convenient, and high in vitamin C. The preparation was simple: empty the container of frozen concentrate into a measured volume of water and stir. However, by the 1980s, food scientists developed a fresher-tasting juice known as reconstituted ready-to-serve juice. Eventually in the 1990s, "not from concentrate" (NFC) orange juice was developed. Orange juice is a common breakfast beverage in the United States.

Due to the importance of oranges to the economy of Florida, "the juice obtained from mature oranges of the species Citrus sinensis and hybrids thereof" was adopted as the official beverage of Florida in 1967.

Nutrition
A cup serving (250 millilitres or 8 ounces) of fresh orange juice is 88% water and contains 26 grams of carbohydrates (including 21 grams of sugar), two grams of protein, and 0.5 grams each of dietary fiber and fat (table). One cup supplies 112 calories and 149% of the Daily Value (DV) of vitamin C, with moderate amounts (11-19% DV) of potassium, thiamin, and folate (table).

Because of its citric acid content, orange juice is acidic, with a typical pH of around 3.5.

As of 2020, consumption of orange juice was under preliminary research for the potential to improve nutrition and affect cardiovascular diseases.

Frozen concentrated orange juice
Commercial squeezed orange juice is pasteurized and filtered before being evaporated under vacuum and heat. After removal of most of the water, this concentrate, about 65% sugar by weight, is then stored at about 10 °F. Essences, Vitamin C, and oils extracted during the vacuum concentration process may be added back to restore flavor and nutrition (see below).

When water is added to freshly thawed concentrated orange juice, it is said to be reconstituted.

The product was developed in 1948 at the University of Florida's Citrus Research and Education Center. Since, it has emerged as a soft commodity, and futures contracts have traded in New York since 1966. Options on FCOJ were introduced in 1985. From the late 1950s to the mid-1980s, the product had the greatest orange juice market share, but not-from-concentrate juices surpassed FCOJ in the 1980s.

Not from concentrate
Orange juice that is pasteurized and then sold to consumers without having been concentrated is labeled as "not from concentrate". Just as "from concentrate" processing, most "not from concentrate" processing reduces the natural flavor from the juice. The largest producers of "not from concentrate" use a production process where the juice is placed in aseptic storage, with the oxygen stripped from it, for up to a year.

Removing the oxygen also strips out flavor-providing compounds, and so manufacturers add a flavor pack in the final step, which Cook's Illustrated magazine describes as containing "highly engineered additives." Flavor pack formulas vary by region, because consumers in different parts of the world have different preferences related to sweetness, freshness and acidity. According to the citrus industry, the Food and Drug Administration does not require the contents of flavor packs to be detailed on a product's packaging.

One common component of flavor packs is ethyl butyrate, a natural aroma that people associate with freshness, and which is removed from juice during pasteurization and storage. Cook's Illustrated sent juice samples to independent laboratories, and found that while fresh-squeezed juice naturally contained about 1.19 milligrams of ethyl butyrate per liter, juice that had been commercially processed had levels as high as 8.53 milligrams per liter.

Canned orange juice
A small fraction of fresh orange juice is canned. Canned orange juice retains vitamin C much better than bottled juice. The canned product loses flavor, however, when stored at room temperature for more than 12 weeks. In the early years of canned orange juice, the acidity of the juice caused the juice to have a metallic taste. In 1931, Dr. Philip Phillips developed a flash pasteurization process that eliminated this problem and significantly increased the market for canned orange juice.

Freshly squeezed, unpasteurized juice
Fresh-squeezed, the unpasteurized juice is the closest to consuming the orange itself. This version of the juice consists of oranges that are squeezed and then bottled without having any additives or flavor packs inserted. The juice is not subjected to pasteurization. Depending on storage temperature, freshly squeezed, unpasteurized orange juice can have a shelf life of 5 to 23 days.

Major orange juice brands
In the U.S., the major orange juice brand is Tropicana Products (owned by PAI Partners and PepsiCo Inc.), which possesses nearly 65% of the market share. Tropicana also has a large presence in Latin America, Europe, and Central Asia. Competing products include Minute Maid (of The Coca-Cola Company) and Florida's Natural Growers (a Floridian agricultural cooperative that differentiates itself from the competition by being locally owned and using only Florida grown oranges; Tropicana and Simply Orange use a mixture of domestic and foreign stock).

In Australia, Daily Juice (owned by National Foods) is a major brand of partially fresh, partially preserved, orange juice.

In the United Kingdom, major orange juice brands include Del Monte and Princes.

Additives
Some producers add citric acid or ascorbic acid to juice beyond what is naturally found in the orange. Some also include other nutrients. Often, additional vitamin C is added to replace that destroyed in pasteurization. Additional calcium may be added. Vitamin D, not found naturally in oranges, may be added as well. Sometimes omega-3 fatty acids from fish oils are added to orange juice. Low-acid varieties of orange juice also are available.

FCOJ producers generally use evaporators to remove much of the water from the juice in order to decrease its weight and decrease transportation costs. Other juice producers generally deaerate the juice so that it can be sold much later in the year.

Because such processes remove the distinct aroma compounds that give orange juice a fresh-squeezed taste, producers later add back these compounds in a proprietary mixture, called a "flavor pack", in order to improve the taste and to ensure a consistent year-round taste. The compounds in the flavor packs are derived from orange peels by squeezing the oil out of them. Producers do not mention the addition of flavor packs on the label of the orange juice.

Types of orange
Common orange juice is made from the sweet orange. Different cultivars (for example, Valencia, Hamlin) have different properties, and a producer may mix cultivar juices to get the desired taste. Orange juice usually varies between shades of orange and yellow, although some ruby red or blood orange varieties are a reddish-orange or even pinkish. This is due to different pigmentation in ruby red oranges.

The blood orange is a mutant of the sweet orange. The mandarin orange and the clementine and tangerine varieties are often used for sparkling juice drinks.

Many brands of organic orange juices have become available on the market.

Manufacture of frozen concentrated orange juice
The processing of orange to frozen concentrated orange juice begins with testing the orange fruit for quality to ensure it is safe for the process. Then the fruit is cleaned and washed thoroughly and orange oil is taken from the peel of the orange. Next, the juice is extracted from the orange and is screened in order to remove seeds and large pieces of pulp. The juice is then heated to 190 to 200 °F in order to inactivate natural enzymes found in the juice. The concentration step occurs in a high vacuum evaporator where the water content in the juice is evaporated while the juice sugar compounds and solids are concentrated. The vacuum evaporator is a low temperature falling film evaporator, which operates at a temperature between 60 and 80 °F. Evaporators work in a continuous manner in that fresh juice is added as concentrate is being constantly removed. The concentration process increases the soluble solid portion of the juice from 12 °Brix to 60-70 °Brix.

The concentrated juice is held in a cold wall tank and is stored at or below 35 °F to prevent browning and development of undesired flavors. Next, a small amount of fresh juice is added to the concentrated juice to restore natural and fresh flavors of orange juice that have been lost through the concentration process. Specific cold-pressed orange oils are used to restore the lost aroma and volatile flavors. After the addition of fresh juice, the brix content is reduced to 42 °F. The fresh juice is referred to as "cut-back" in the industry and attributes to 7-10% of the total juice. Orange peel oil is also added if the oil content is below the required level. The concentrate is then further cooled in a continuous cooler or cold wall tank to 20 to 25 °F. The concentrate is canned using steam injection methods to sterilize the lid and develop a vacuum in the can. The cans then undergo final freezing where they are conveyed on a perforated belt in an air blast at -40 °F. After freezing, the product is stored at 0 °F in a refrigerated warehouse.

Manufacture of "not from concentrate"
Single strength orange juice (SSOJ) can either be "not from concentrate" (NFC) orange juice or juice that is reconstituted from a concentrate with the addition of water to reach a specific single strength brix level. The processing of SSOJ also begins with the selection of orange. The most common types of orange used to produce orange juice are the Pineapple orange, Valencia orange, and Washington Navel oranges from Florida and California. The manufacturing journey begins when oranges are delivered to processing plants by trucks holding about 35,000 to 40,000 pounds of fruit. The fruit is unloaded at the plant for inspection and grading to remove unsuitable fruit before the oranges enter the storage bins. An automatic sampler removes oranges for determination of acid and soluble solids. The bins are organized based on ratio of soluble solids to acids in order to blend oranges appropriate to produce juice with uniform flavor. After the fruit leaves the bins, they are scrubbed with detergent on a rotary brush washer and subsequently rinsed with potable water. Throughout the processing stages, there are multiple points with facilities that inspect oranges and discard damaged fruit.

The oranges then go through roller conveyors, which expose all sides of the fruit. The roller conveyors are efficiently built as they are well lighted, installed at a convenient height, and width to ensure all inspectors can reach the fruit to determine inadequacies. Some reasons why fruit may be rejected include indication of mold, rot, and ruptured peels. Afterwards, the oranges are separated based on size through machines prior to juice extraction. There are a number of different ways orange juice industry leaders extract their oranges. Some common methods include halving the fruit and pressing/reaming the orange to extract juice from the orange. One instrument inserts a tube through the orange peel and forces the juice out through the tube by squeezing the entire orange. Despite the variety of machines used to extract juices, all machines have commonalities in that they are rugged, fast, easy to clean and have the ability to reduce peel extractives into the juice. The extracted juice product does not contain the orange peel, but it may contain pulp and seeds, which are removed by finishers.

Finishers have a screw-type design that comprises a conical helical screw enclosed in a cylindrical screen with perforations the size of 0.020 to 0.045 inches. Thereafter, the finished orange juice flows through blending tanks where the juice is tested for acid and soluble solids. At this stage, sugar can be added to the juice depending on if the product will be a sweetened or unsweetened beverage. Following blending, the orange juice is deaerated where the air is incorporated into the juice during extraction. The benefits of deaeration include the elimination of foaming, which improves the uniformity of can fill and improvement regarding the efficiency of the heat exchanger. Orange peel oil is essential for maximum flavor, but according to U.S. standards for Grades of Canned Orange Juice, 0.03% of recoverable oil is permitted. Deoiling through the use of vacuum distillation is the mechanism used to regulate the amount of peel oil in the juice. Condensation separates the oil and the aqueous distillate, which is returned to the juice.

The next step is one of the most vital in the processing of orange juice. Pasteurization is important in destroying naturally occurring enzymes that are associated with deterioration of the juice. Pectinesterase is infamous for its deteriorative activity in orange juice. In the pasteurization process, the juice is generally rapidly heated to 197 °F for about 40 seconds. Several industry leaders use flash pasteurization, which is carried out by tubular or plate-type heat exchangers. In order to prevent overheating, turbulent flow is vital to heat the juice rapidly. Cans are filled with the pasteurized juice and inverted immediately to allow the juice to sterilize the inside parts of the lid. The orange juice filled can is sealed and cooled to 90 to 100 °F by spinning on the conveyor belt under cool water sprays. Quality of storage is determined by time and temperature. Juice must be stored at cool temperatures to prevent deterioration.

Regulations in Canada
For Canadian markets, orange juice must be the fruit juice obtained from clean, sound, and mature oranges. The juice must also contain a minimum of 1.20 milliequivalents of free amino acids per 100 millilitres, contain a minimum of 115 milligrams of potassium per 10 milliliters, and possess a minimum absorbance value for total polyphenolics of 0.380. Sweeteners such as sugar, invert sugar, dextrose or glucose solids may be added. The orange juice must have a Brix reading of at least 9.7, excluding the sweetening ingredients, and contain between 0.5 and 1.8 percent of acid by weight calculated as anhydrous citric acid. Added orange essences, orange oils and orange pulp adjusted in accordance with good manufacturing practice is permitted. Orange juice is also permitted to contain sugar, invert sugar, dextrose in dry form, glucose solids, a Class II preservative, amylase, cellulase and pectinase.

Regulations in the United States
In the United States, orange juice is regulated and standardized by the Food and Drug Administration (FDA or USFDA) of the United States Department of Health and Human Services. According to the FDA, orange juice from concentrate is a mixture of water with frozen concentrated orange juice or concentrated orange juice for manufacturing. Additional ingredients into the mixture may include fresh/frozen/pasteurized orange juice from mature oranges, orange oil, and orange pulp. Furthermore, one or more of the following optional sweetening ingredients may be added: sugar, sugar syrup, invert sugar, invert sugar syrup, dextrose, corn syrup, dried corn syrup, glucose syrup, and dried glucose syrup. The orange juice must contain a minimum Brix level of 11.8, which indicates the percentage of orange juice soluble solids, excluding any added sweetening ingredients.

Regulations in the United Kingdom
In the United Kingdom, orange juice from concentrate is a product of concentrated fruit juice with the addition of water. Any lost flavour or pulp of the orange juice during the initial concentration process may be restored in the final product to be equivalent to an average type of orange juice of the same kind. Any restored flavour or pulp must come from the same species of orange. Sugar may be added to the orange juice for regulating the acidic taste or sweetening, but must not exceed 150g per litre of orange juice. Across the UK, the final orange juice from concentrate product must contain a minimum Brix level of 11.2, excluding the additional sweetening ingredients. Vitamins and minerals may be added to the orange juice in accordance with Regulation (EC) 1925/2006.

Molecular composition

On a molecular level, orange juice is composed of organic acids, sugars, and phenolic compounds. The main organic acids found in orange juice are citric, malic, and ascorbic acid. The major sugars found in orange juice are sucrose, glucose, and fructose. There are approximately 13 phenolic compounds in orange juice including hydroxycinnamic acids, flavanones, hydroxybenzoic acids, hesperidin, narirutin, and ferulic acid.

Composition of the cloud
The cloud is the portion of suspended particles that range in size from 0.05 micrometers to a few hundred micrometers in orange juice. The cloud is responsible for several sensory attributes in orange juice including color, aroma, texture, and taste. The continuous medium of the cloud consists of a solution of sugars, pectin, and organic acids while the dispersed matter is formed through cellular tissue comminuted in fruit processing. Specifically, the cloudiness of the juice is caused by pectin, protein, lipid, hemicellulose, cellulose, hesperidin, chromoplastids, amorphous particles, and oil globules. In particular the chemical composition of the cloud consists of 4.5-32% pectin, 34-52% protein, 25% lipids, 5.7% nitrogen, 2% hemicellulose, 2% ash, and less than 2% cellulose.

Physical structure
Orange juice is a suspension that consists of heterogeneous particles in a clear serum. A serum is the clear supernatant after the precipitation of the cloud through centrifugation. The previously mentioned cloud makes up a large part of the suspension.

If the suspension in orange juice is not stable, the cloud particles can flocculate which causes the suspension to physically decompose. The cloud can break apart and the citrus juice will clarify if the suspension becomes unstable. The activity of pectin methyl esterase increased the interaction between pectin and cloud proteins, which led to protein-pectin flocculation. The insoluble material of the cloud clumps in conditions above 70 C and at a pH of 3-4 at which proteins coagulate and flocculate. Cloud flocculation is enhanced at pH 3.5 and can result in clarification, which is undesirable in orange juice.

The suspension is unstable when the zeta potential is less than 25 mv in magnitude. Zeta potential is a measure of the magnitude of electrostatic forces between particles, which affect repulsion, and attraction between particles. A low zeta value signifies that the repulsive forces will not be able to overcome Van der Waals attractions between cloud particles and thus begin to agglomerate. Agglomeration of cloud particles will prevent free flow characteristics, which is essential in the juice. A high zeta potential will inhibit particle-particle agglomeration and maintain the free flowing nature as well as uniform dispersion in orange juice.

The oil globules adsorbed to the cloud particles stabilize the suspension by decreasing the average density of particles to bring it closer to that of the serum. However, large amounts of oil can be problematic as they cause complete breakdown of suspensions by causing cloud particles to float to the surface. The particles in the cloud have a negative charge that decreases with decreasing pH. In accordance with cloud stability, the hydration of particles is more significant than their electrical charge.

Heat treatment
When orange juice is heat treated there is an increase in the number of fine particles and decrease in that of coarse particles. The fine particles in particular are responsible for the appearance, color, and flavor of orange juice. Heat treatment plays a vital role on pulp volume, cloud stability, serum turbidity, and serum viscosity. Heat treatment stabilizes the cloud through enzyme inactivation and enhances the turbidity of a stable cloud formation. The increase in serum viscosity is due to the extraction of pectic substances into the serum. Based on Stoke's law, the increase in serum viscosity is the cause for the enhanced cloud stability. In relation to pulp volume, the pulp from heated juices was finer and more compact than unheated juice pulp, which was voluminous and fluffy.

Properties of pulp
In orange juice, pulp is responsible for desirable flow properties, taste, flavor, and mouth feel. However, pulpy orange juice precipitates based on a rate dependent on the diameter, density, and viscosity of the suspended particles as well as the suspending juice. In order to remain suspended in orange juice, pulp particles must have appropriate particle size, charge, and specific gravity. Depending on type of processing method, the size of pulp particles ranges from 2 –. Those that are smaller than 2 mm are known to be more stable, so it is beneficial to reduce the size of particles by incorporating hydrocolloids to the juice product. Hydrocolloids would decrease the rate of sediment formation and decrease the falling rate of pulp particles.

Hydrocolloids
Hydrocolloids are long-chain polymers that form viscous dispersions and gels if dispersed in water. They have a number of functional properties in food products including emulsifying, thickening, coating, gelling, and stabilization. The main reason hydrocolloids are used in foods is their capability to modify the rheology of food systems. Hydrocolloids impact viscosity through flow behavior and mechanical solid properties like texture. Some common hydrocolloids that are used to stabilize juice products include gellan gum, sodium carboxymethylcellulose, xanthan, guar gum, and gum Arabic. The aforementioned hydrocolloids are generally used in the production of imitation orange juices and are often referred to as synthetic hydrocolloids. Pectin is the hydrocolloid found in natural orange juices.

Properties of pectin
Pectin is the soluble polymeric material in the pulp of oranges, which contains 75% of carboxyl of arabinose and galactose. Pectic compounds are complex heteropolysaccharides in that their chemical composition includes a chain structure of axial-axial α-1.4-linked d-galacturonic acid unit along with blocks of L-rhamnose regions that have side chains of arabinose, galactose, and xylose. Pectin methyl-esterase is the enzyme responsible for hydrolyzing carboxymethyl esters and liberating free carboxyl groups and methyl alcohols. The free carboxyl groups interact with cations to form insoluble pectic acid divalent metal ion complexes. These metal ion complexes precipitate in the juice and carry all the colloids in orange juice with it. The enzyme would flocculate the cloud and clarify the orange juice. Thus, in order to keep the orange juice cloud intact, it is vital to inactivate pectinesterase. Pectinesterase is inactivated by heating the juice for 1 minute at 90 C.

Interactions of pectin
The solution behavior of pectin is strongly influenced by a number of factors including hydrogen bonding, ionic character, and hydrophobic character. Hydrogen bonding is favored when pH is less than pKa while the ionic character is favored when pH is greater than pKa. Ionic character relies on free carboxyl content, the presence of cations, and is favored at a high water activity. Charge-charge repulsions along with the presence of neutral side chains are essential in inhibiting intermolecular association among pectin molecules. The methyl ester content in orange juice determines hydrophobic character, which is favored at low water activity.

There is a specific interaction between pectin and hesperidin through the sugar moieties in the hesperidin molecule. Through acid hydrolysis, the rhamnose and glucose sugar moieties are removed from hesperidin, which breaks the interaction between hesperidin and pectin. Hydrogen bonding plays a role in the specific interaction of neutral sugars of pectin and the sugar moiety of hesperidin. A polymer that has a high structural content of neutral sugar branches interacts with hesperidin more tightly and strongly than that of a low content of neutral sugar branches. The interaction between pectin and hesperidin is one of the factors that enable the colloidal suspension in orange juice to be stable.

title: Orange juice


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Fountain Valley, California

Fountain Valley is a suburban city in Orange County, California. The population was 57,047 at the 2020 census.

Indigenous
The Indigenous people of the Fountain Valley area are the Tongva. The closest village to present-day site of the city was the village of Pasbenga. The village was part of a series of villages along what the Spanish would refer to as the Santa Ana River.

Spanish
European settlement of the area began when Manuel Nieto was granted the land for Rancho Los Nietos, later Rancho Las Bolsas, which encompassed over 300000 acre, including present-day Fountain Valley. Control of the land was subsequently transferred to Mexico upon independence from Spain, and then to the United States as part of the Treaty of Guadalupe Hidalgo.

Talbert
Talbert was a settlement at what is now the intersection of Talbert and Bushard. It was also known as Gospel Swamp by residents.

Thomas B. Talbert was born outside Monticello in Piatt County, Illinois, in 1878. When Talbert was 13, his family moved to Long Beach, California. Around 1896, the family purchased more than 300 acre of peat and swampland in what is now Fountain Valley. The Talberts opened a general store and thus the settlement of Talbert was established.

The area was full of farms growing beets that were processed at some of the nation's largest plants at Huntington Beach (Holly Sugar Plant) and at Delhi, now part of southwestern Santa Ana. The post office was established in 1899, with Thomas B. Talbert serving as the first postmaster.

The All-Saints Church is the only structure remaining from that era. The Santa Ana–Huntington Beach Line of the Pacific Electric Railway passed through Talbert and opened on July 5, 1909.

Incorporation
The city was incorporated in 1957. The name of Fountain Valley refers to the very high water table in the area at the time the name was chosen, and the many corresponding artesian wells in the area. Early settlers constructed drainage canals to make the land usable for agriculture, which remained the dominant use of land until the 1960s, when construction of large housing tracts accelerated. The first mayor of Fountain Valley was James Kanno, who with this appointment became one of the first Japanese-American mayors of a mainland United States city.

After the Fall of Saigon in 1975, there was a large influx of Vietnamese refugees settling in Fountain Valley, especially in the late 1970s and throughout the 1980s, forming a large percentage of Asian Americans in the city.

Geography
The city is located southwest and northeast of the San Diego Freeway (Interstate 405), which diagonally bisects the city, and is surrounded by Huntington Beach on the south and west, Westminster and Garden Grove on the north, Santa Ana on the northeast, and Costa Mesa on the southeast. Its eastern border is the Santa Ana River.

According to the United States Census Bureau, the city has a total area of 23.4 km2, 0.14% of which is water.

Community amenities
Fountain Valley is home to Mile Square Regional Park, a 640 acre park containing two lakes, three 18-hole golf courses, playing fields, picnic shelters, and a 20 acre urban nature area planted with California native plants, a 55 acre recreation center with tennis courts, basketball courts, racquetball courts, a gymnasium, and the Kingston Boys & Girls Club; There is also a community center and a 16,652 ft2 senior center that opened in September 2005. A major redevelopment of the recreation center and city-administered sports fields was completed in early 2009.

Fire protection and emergency medical services are provided by two stations of the Fountain Valley Fire Department. Law enforcement is provided by the Fountain Valley Police Department. Ambulance service is provided by Care Ambulance Service.

The Orange County Sanitation District's administrative offices and primary plant is located in Fountain Valley next to the Santa Ana River. The agency is the third-largest sanitation district in the western United States. Fountain Valley is also home to the offices of the Municipal Water District of Orange County, a member of the Metropolitan Water District of Southern California and of the Orange County Water District. The Orange County Water District manages the groundwater basin in central and northern Orange County and operates the Groundwater Replenishment System, the world's largest water purification plant for groundwater recharge.

Fountain Valley has two fully accredited major medical centers: the Fountain Valley Regional Hospital with 400 beds available, and Orange Coast Memorial Medical Center with 230 beds, a medical clinic, and an outpatient medical building.

The city also has 18 churches, one Reform synagogue, a mosque and a public library.

Fountain Valley has its own newspaper, the Fountain Valley View, operated by the Orange County Register.

Economy
As a suburban city, most of Fountain Valley's residents commute to work in other urban centers. However, in recent years, the city has seen an increase in commercial jobs in the city, with the growth of a commercial center near the Santa Ana River known as the "Southpark" district.

Although the economy of the area was once based mainly on agriculture, the remaining production consists of several fields of strawberries or other small crops, which are gradually being replaced by new office development. Efforts to bolster economic activity are evidenced by the city enacting policies to benefit small businesses, and even going so far as to paint a mural on the facade of a large water treatment building facing the freeway that depicts two shopping bags headlined by the words, "Shop in Fountain Valley."

Fountain Valley is home to the national headquarters of Hyundai Motor America and D-Link Corporation, the global headquarters of memory chip manufacturer Kingston Technology, and the corporate headquarters of Surefire, LLC, maker of military and commercial flashlights. The Southpark commercial area is also home to offices for companies such as D-Link, Starbucks, Satura and the Orange County Register. There are also a limited number of light industrial companies in this area. In addition, Fountain Valley is the location for Noritz, a tankless water heater manufacturer, and the main west coast offices of Ceridian, a professional employer organization.

The increasing commercial growth can be evidenced by the frequent rush-hour traffic bottlenecks on the San Diego (405) Freeway through Fountain Valley.

Top employers
According to the city's 2023 Annual Comprehensive Financial Report, the top ten employers in the city are:

Arts and culture
Fountain Valley holds an annual Summerfest in June in Mile Square Regional Park. The event features a car show, rides, music, and booths.

Education
There are three high schools, three middle schools, nine elementary schools, one K-12 school, and two K-8 schools. However, some students who live in the city of Fountain Valley actually attend schools in other cities.

Fountain Valley is also home to Coastline Community College. Community colleges in the area include Orange Coast College and Golden West College, located nearby in the cities of Costa Mesa and Huntington Beach, respectively.

High schools in Huntington Beach Union High School District
 * Fountain Valley High School
 * Valley Vista High School

High schools in Garden Grove Unified School District
 * Los Amigos High School

Middle schools in Fountain Valley School District
 * Harry C. Fulton Middle School
 * Kazuo Masuda Middle School: Named for Kazuo Masuda, a soldier who fought in World War II and now is buried in Midway City, California.
 * Talbert Middle School

Middle schools in Ocean View Middle School District
 * Vista View Middle School

Elementary schools in Garden Grove Unified School District
 * Allen Elementary School, a 2011 Blue Ribbon Award winner
 * Monroe Elementary School
 * Northcutt Elementary School

Elementary schools in Fountain Valley School District

 * Courreges Elementary School
 * Cox Elementary School
 * Gisler Elementary School
 * Plavan Elementary School
 * Tamura Elementary School
 * Newland Elementary School
 * Oka Elementary School (located in Huntington Beach)

Private schools
 * Shoreline Christian School (K-8)

The Lycée International de Los Angeles previously had its Orange County campus in Fountain Valley, but it moved to Orange by 2001.

Transportation
In addition to the San Diego Freeway, which bisects the city, Fountain Valley is served by several bus lines operated by the Orange County Transportation Authority. Bus routes 33, 35, 37, 43, 70, 72, 76 and 543 cover the city's major streets.

Most of the major roads are equipped with bicycle lanes, especially around Mile Square Park, which offers wide bike paths along the major streets that mark its boundary. Dedicated bike paths along the Santa Ana River run from the city of Corona to the Pacific Ocean.

Historically, Fountain Valley had Red Car service along the Santa Ana/Huntington Beach Pacific Electric Spur Line. This line ran along Bushard Street. Passenger service started in 1909, ended in 1922, and the lines were torn out in 1930.

2010
The 2010 United States Census reported that Fountain Valley had a population of 55,313. The population density was 6,124.7 PD/sqmi. The racial makeup of Fountain Valley was 31,225 (56.5%) White (49.2% Non-Hispanic White), 510 (0.9%) African American, 229 (0.4%) Native American, 18,418 (33.3%) Asian, 171 (0.3%) Pacific Islander, 2,445 (4.4%) from other races, and 2,315 (4.2%) from two or more races. Hispanic or Latino of any race were 7,250 persons (13.1%).

The Census reported that 54,876 people (99.2% of the population) lived in households, 257 (0.5%) lived in non-institutionalized group quarters, and 180 (0.3%) were institutionalized.

There were 18,648 households, out of which 6,341 (34.0%) had children under the age of 18 living in them, 11,142 (59.7%) were opposite-sex married couples living together, 2,102 (11.3%) had a female householder with no husband present, 970 (5.2%) had a male householder with no wife present. There were 646 (3.5%) unmarried opposite-sex partnerships, and 108 (0.6%) same-sex married couples or partnerships. 3,451 households (18.5%) were made up of individuals, and 1,772 (9.5%) had someone living alone who was 65 years of age or older. The average household size was 2.94. There were 14,214 families (76.2% of all households); the average family size was 3.34.

The population was spread out, with 11,643 people (21.0%) under the age of 18, 4,624 people (8.4%) aged 18 to 24, 13,310 people (24.1%) aged 25 to 44, 16,020 people (29.0%) aged 45 to 64, and 9,716 people (17.6%) who were 65 years of age or older. The median age was 42.6 years. For every 100 females, there were 94.9 males. For every 100 females age 18 and over, there were 92.2 males.

There were 19,164 housing units at an average density of 2,122.0 /sqmi, of which 13,458 (72.2%) were owner-occupied, and 5,190 (27.8%) were occupied by renters. The homeowner vacancy rate was 0.8%; the rental vacancy rate was 3.8%. 40,718 people (73.6% of the population) lived in owner-occupied housing units and 14,158 people (25.6%) lived in rental housing units.

According to the 2010 United States Census, Fountain Valley had a median household income of $81,212, with 6.7% of the population living below the federal poverty line.

2000
According to the census of 2000, there were 54,978 people, 18,162 households, and 14,220 families residing in the city. The population density was 6,167.8 /mi2. There were 18,473 housing units at an average density of 2,072.4 /sqmi. The racial makeup of the city was 64.02% White, 1.11% Black or African American, 0.46% American Indian or Alaskan Native, 10.68% of the population were Hispanic or Latino of any race. 25.76% Asian, 0.40% Native Hawaiian or other Pacific Islander, 3.95% from other races, and 4.3% from two or more races.

There were 18,162 households, out of which 34.3% had children under the age of 18 living with them, 63.4% were married couples living together, 10.5% had a female householder with no husband present, and 21.7% were non-families. 16.0% of all households were made up of individuals, and 5.5% had someone living alone who was 65 years of age or older. The average household size was 3.00 and the average family size was 3.35.

In the city, the population was spread out, with 23.5% under the age of 18, 7.9% from 18 to 24, 30.1% from 25 to 44, 27.2% from 45 to 64, and 11.3% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 95.6 males. For every 100 females age 18 and over, there were 93.0 males.

The median income for a household in the city was $78,729, and the median income for a family was $90,335. Males had a median income of $60,399 versus $43,089 for females. The per capita income for the city was $48,521. About 1.6% of families and 2.3% of the population were below the poverty line, including 3.2% of those under age 18 and 3.0% of those age 65 or over.

Government
In the California State Legislature, Fountain Valley is in, and in.

In the United States House of Representatives, Fountain Valley is in.

Politics
Fountain Valley is a reliably Republican stronghold in presidential elections; however, former Secretary of State Hillary Rodham Clinton won a plurality of the city in 2016, becoming the first Democrat in over four decades to carry the municipality. However, in 2020, the city moved back into the Republican column, as Donald Trump carried the city with 51.0% of the vote, having made gains in Orange County's Vietnamese community.

According to the California Secretary of State, as of October 22, 2018, Fountain Valley has 32,884 registered voters. Of those, 12,935 (39.34%) are registered Republicans, 9,674 (29.42%) are registered Democrats, and 8,967 (27.27%) have declined to state a political party/are independents.

Notable people

 * Summer Altice, model, actress, August 2000 Playboy Playmate of the Month.
 * Nicholas Altobelli, musician.
 * Rony Argueta, soccer player.
 * Mary Astor, Academy Award for Best Supporting Actress; moved to Fountain Valley.
 * Tara Lynne Barr, actress; raised in Fountain Valley.
 * Jenny Benson, soccer player.
 * Kenney Bertz, soccer player.
 * Brian Brushwood, magician, podcaster, author, lecturer known for Scam School
 * Roger H. Chen, businessman; moved to Fountain Valley.
 * Don Clark, football player.
 * Brandon Crouch, evangelist.
 * Travis Denker, baseball player.
 * Jack Evans, professional wrestler.
 * Willie Eyre, baseball player.
 * Amanda Freed, Olympic gold medal-winning softball player.
 * Freddie Freeman, baseball player.
 * K. J. Gerard, football player.
 * Kim Gruenenfelder, writer, attended high school in Fountain Valley
 * Ryan Hansen, actor.
 * Carl Harry, football player.
 * Mike Hessman, baseball player.
 * Michael Hoyos, soccer player.
 * Luke Hudson, baseball player: Kansas City Royals pitcher.
 * Justin Huish, Olympic gold medalist.
 * Casey Janssen, baseball player.
 * Duy Khánh, musician; lived in Fountain Valley.
 * Chay Lapin, Olympian.
 * Ken Margerum, football player, Chicago Bears and San Francisco 49ers wide receiver, San Jose State college football assistant coach
 * Dan McClintock, basketball player.
 * Jerry M. Patterson, U.S. House of Representatives, California's 38th congressional district (1975–1985); Resident of Fountain Valley.
 * Michelle Pfeiffer, actress, graduate of Fountain Valley High School Class of 1976
 * Mike Pompeo, Los Amigos High School Grad (Class of 1982), US Secretary of State (2018–2021), Former Director of the Central Intelligence Agency (2017–18), Former Member of United States House of Representatives – Kansas 4th Congressional District (2011–2017)
 * Isiah Robertson, NFL player, Los Angeles Rams; lived in Fountain Valley.
 * Keri Russell, actress.
 * Art Satherley, record producer.
 * Nick Scandone, Paralympian.
 * Aaron Schoenke, actor, screenwriter, director, editor, producer, cinematographer.
 * M. Shadows, lead singer of Avenged Sevenfold
 * David Sias, soccer player.
 * Andre Sommersell, football player.
 * Vai Taua, football player.
 * Dale Thayer, baseball player.
 * Chris Tillman, baseball player.
 * Brian Van Holt, actor, graduate of Fountain Valley High School Class of 1987
 * Craig Wilson, baseball player.
 * C. J. Wilson, baseball player.
 * Beau Wirick, actor.
 * Chung Yong Taek, martial artist; lived in Fountain Valley.
 * Tom McEwen, drag racer, lived in Fountain Valley.
 * Laura Yeager, U.S. Army general, grew up in Fountain Valley.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Fountain Valley, California


text:
Fremont, California

Fremont is a city in Alameda County, California, United States. Located in the East Bay region of the Bay Area, Fremont has a population of 230,504 as of 2020, making it the fourth most populous city in the Bay Area, behind San Jose, San Francisco, and Oakland. It is the closest East Bay city to the high-tech Silicon Valley network of businesses, and has a strong tech industry presence.

The city's origins lie in the community that arose around Mission San José, founded in 1797 by the Spanish under Padre Fermín Lasuén. Fremont was incorporated on January 23, 1956, when the former towns of Mission San José, Centerville, Niles, Irvington, and Warm Springs unified into one city. Fremont is named after John C. Frémont, a general who helped lead the American Conquest of California from Mexico and later served as Military Governor of California and then U.S. Senator.

Early history
The recorded history of the Fremont area began on June 6, 1797, when Mission San José was founded by the Spaniard Father Fermín de Lasuén. The Mission was established at the site of the Ohlone village of Oroysom. The tribe lived between present-day San Francisco and Monterey and more lands eastward. They lived in dome-shaped shelters made out of redwood bark or woven tule. They were primarily hunter-gatherers; men hunted and trapped waterfowl, rabbits, deer, elk, and bears, whilst women gathered nuts, berries, and root vegetables. The Ohlone tribe lived beside rivers and estuaries because of the natural resources like fish and shellfish. In warm weather, men wore mostly nothing; in the winter, they wore animal hide or feather capes. Other than the weather, ceremonies also decided what the Ohlone men wore. The women wore deerskin aprons over skirts made of tule or shredded bark.

Until 1769, the tribe lived peacefully but Spanish soldiers and missionaries arrived in California to expand Spanish dominion in the Americas and convert the Native Americans to Catholicism. The Ohlone people weren't intimidated by the Franciscan priests, who welcomed them into their missions to live and work. Before missions, the Natives used tools made of stone, animal bones, and wood. The missionaries taught them how to make metal tools and weapons and priests also showed them how to make adobe bricks. The bricks were then used to build missions rather than for the tribe to utilize. The Spaniards brought cattle, pigs and sheep and encouraged the Ohlone to give up hunting and gathering to try farming and ranching instead. Living in the missions meant Ohlone people were forced into converting to Christianity and told to forget the superstitious beliefs that connected them to nature. Along with that, overpopulation caused food shortages and the Spanish brought diseases to the tribe, causing a lot of deaths and trouble that made an impact on a lot of lives.

On their second day in the area, the Mission party killed a grizzly bear in Niles Canyon. The first English-speaking visitor to Fremont was the renowned trapper and explorer Jedediah Smith in 1827. The Mission prospered, eventually reaching a population of 1,887 inhabitants in 1831. The influence of the missionaries declined after 1834 when the Mexican government enacted secularization.

José de Jesus Vallejo, brother of Mariano Vallejo, was the grantee of the Rancho Arroyo de la Alameda Mexican land grant. His family was influential in the Fremont area in the late colonial era and owned and built a flour mill at the mouth of Niles Canyon. In 1846 the town's namesake John C. Frémont led a military expedition to map a trail through Mission Pass for reaching the Pacific coast and to take possession of California from Mexico for the United States. The Fremont area grew rapidly at the time of the California Gold Rush. A town called Mission San José grew up around the old mission, with its own post office from 1850. Agriculture dominated the economy with grapes, nursery plants and olives as leading crops. In 1868 the 6.8-magnitude Hayward earthquake on the Hayward Fault collapsed buildings throughout the Fremont area, ruining Mission San José and its outbuildings. Until the 1906 San Francisco earthquake caused its destruction, the Fremont area's Palmdale Winery was the largest in California. The ruins of the Palmdale Winery are still visible near the Five Corners in Irvington at the intersection of Washington Boulevard and Osgood. From 1912 to 1915, the Niles section of the Fremont area was the earliest home of California's motion picture industry (see Essanay Studios). Charlie Chaplin filmed several movies in the Fremont area, most notably The Tramp.

Incorporation
Fremont was incorporated in 1956 under the leadership of Wally Pond, chair of the incorporation committee, when five towns in the area, Irvington, Centerville, Mission San José, Niles, and Warm Springs, came together to form a city. Glenmoor Gardens, the largest subdivision in Fremont, was under construction in the area, by developers Ralph E. Cotter Jr., James R. Meyer, civil engineer Fred T. Duvall, and contractors James L. Reeder, and Robert H. Reeder. When the Glenmoor Gardens Homeowners Association (GGHA) was incorporated, in March 1953, there were no more than 75 houses in the subdivision. It was probably the first such organization in the Fremont area; in its scope and structure. The five-member board of directors (which included James Meyer and James Reeder) was set up to oversee a full range of services, from police and fire protection to street maintenance (which later became the purview of the city government).

Fremont became more industrialized between 1953 and 1962. The first Fremont post office opened in 1956. A boom in high-tech employment in the 1980s to the late 1990s, especially in the Warm Springs District, caused rapid development in the city and linked the city with the Silicon Valley. The Apple factory where the first Mac computer was manufactured was located in Fremont; production ceased in 1993. Other semiconductor and telecommunications firms soon opened in the city, including Cirrus Logic, Asyst Technologies, Mattson Technology, Lam Research, Premisys Communications, and Nextlink California. Approximately 750 high tech companies had offices, headquarters or production facilities in Fremont by 1999. These firms included fifteen of the top one hundred fastest-growing public companies in the San Francisco Bay Area and eighteen of the top fifty companies in the East Bay. The high-tech growth in Fremont continues today and is a major industry for the city.

The General Motors automotive assembly plant in South Fremont was the town's largest employer, and Fremont was known for its drag strip. In the 1980s, the plant became a joint venture automotive assembly plant of Toyota and General Motors, and was renamed NUMMI. Toyota and NUMMI shut down its operations in early 2010. Part of the plant was acquired in June 2010 by Tesla Motors as its primary production plant, known as the Tesla Factory.

Solyndra, a solar panel manufacturer, was promoted in 2010 by President Barack Obama as a model for government investment in green technology after his administration approved a $535-million Department of Energy loan guarantee and the company built a $733 million state-of-the-art robotic facility, but in 2011 the company filed for Chapter 11 bankruptcy and laid-off 1,000 workers. Data storage company Seagate Technology, incorporated in the Republic of Ireland with executive offices in Cupertino, acquired the former Solyndra building, which serves as Seagate's headquarters since 2020.

Geography
In 1956, five small, independent towns (Centerville, Niles, Irvington, Mission San José, and Warm Springs) located between the East Bay rolling hills and the San Francisco Bay were annexed into a single new, incorporated city called Fremont. Six decades later, these places have greatly expanded, are no longer separate communities, and are considered districts or community plan areas of the City of Fremont. The town of Newark was originally slated to join the annex, but ultimately its voters declined since Newark representatives suspected that they would become an industrial district; Newark became its own incorporated city in 1955. Later, Newark annexed a patch of unincorporated land between Mowry Avenue and Stevenson Blvd; Land which is now occupied by Newpark Mall and the surrounding plazas. Since incorporation, Fremont has created six more districts, which it calls "community plan areas" for planning purposes. These include Central, North Fremont, South Fremont, and Bayside. The two other districts, Baylands and the Hill Areas, are primarily open space.

The area consisting of Fremont and the cities of Newark and Union City is known collectively as the Tri-City Area (different from the adjacent Tri-Valley area encompassing Pleasanton, Dublin, and Livermore).

Centerville District
Centerville was formerly the main town in Washington Township. Centerville is located at 37.55417°N, -121.99917°W. It lies at an elevation of 52 ft. Centerville was started by George Lloyd who started selling cold beer to stage passengers from a tent in 1850. Capt. George Bond set up a general store and the name Centerville was chosen. The post office opened Centreville post office in 1855 and changed the spelling to Centerville in 1893. The Centerville Pioneer Cemetery contains the burial places of many of the city's founding pioneers.

Centerville can be traced back to its native American roots. Spanish, Mexican, Italian, Portuguese and Swiss (Swiss Park), peoples were among the early settlers that contributed greatly to the growth of Centerville.

Early Centerville was a quiet farming community, which consisted of large Spanish land grants divided into smaller farms. The Freitas Ranch on Thornton Ave was probably the largest of the working farms. There were acres of apricot along with other fruit and nut orchards and large fields of various types of fresh produce.

After President Roosevelt issued Executive Order 9066, which authorized military commanders to exclude "any or all persons" from certain areas in the name of national defense, the Western Defense Command began ordering Japanese Americans living on the West Coast to present themselves for "evacuation" from the newly created military zones. This included many Centerville farming families.

Centerville was also a main stop for the early railways. This gave the local farmers a way to quickly get their produce to market. With the access to railway service there was once a large cannery on Baine Ave. west of Fremont Ave. (now Peralta) next to the tracks. In 1959, the cannery was destroyed in the largest fire in Fremont's history. The fire lasted for two days, and effectively put an end to what had been the largest employer in Centerville at the time. The cannery was never rebuilt.

Housing developments began to appear in the area after WWII. Most of the early housing stood along Fremont Blvd from Decoto Road south to Washington High school, along Thornton Ave from Fremont Blvd west to the Newark city border, and along Peralta Blvd from Fremont Blvd to Niles.

For city planning purposes, Centerville was enlarged to encompass most of the north central residential section of Fremont, from Mowry Ave to Decoto Rd, from I-880 to the BART line. This Centerville community plan area includes the sprawling subdivisions, developed in the 1950s and 1960s, of Glenmoor Gardens, bounded by Central Avenue, Fremont Boulevard, Mowry Avenue, and the I-880 freeway. and the Cabrillo Park subdivision bound by Thornton Ave, Fremont Blvd, Decoto Road and the I-880 freeway. Also the Brookvale subdivisions, the Quarry Lakes Regional Park, and part of Parkmont. The area is served by two high schools, Washington High School (Fremont, California) established in 1892, which for a long time was the only high school in the area and American High School established in 1972. It also has two junior high schools, Centerville Junior High School and Thornton Junior High School, which now stands on the old main site of the Freitas ranch.

Niles District
The former town of Niles is physically divided from other parts of Fremont and neighboring Union City by Mission Boulevard (State Route 238) to the east and north, Alameda Creek to the south, Union Pacific Railroad to the west and southeast, and the Quarry Lakes to the southwest. The hills of Niles are lower than those of the area south of the Alameda Creek in Mission San Jose. Old Town Niles features its own library, post office, and silent movie theater as well as a large number of antique and craft stores. Niles is located at 37.57889°N, -121.97778°W. It lies at an elevation of 112 ft.

The community, once called Vallejo Mills, got its name from the Central Pacific Railroad's Niles junction and station, opened in April 1870 as part of the First transcontinental railroad and named after their railroad attorney and stockholder Addison Niles, who became associate justice on the California Supreme Court two years later. A post office was opened at Niles on Vallejo Street in 1873.

Niles was the West Coast home (1912–1916) of one of the first motion picture companies, Essanay Studios. Charlie Chaplin and Broncho Billy Anderson filmed some of their most famous silent movies in Niles and the scenic Niles Canyon that stretches between Niles and Sunol. The nonprofit Niles Essanay Silent Film Museum offers both artifacts of Niles' early years and, each Saturday evening, screenings of early-twentieth-century silent films, many of which were filmed locally.

The Niles Canyon Railway runs along Alameda Creek in Niles Canyon and carries passengers on weekend excursions, including a holiday "train of lights", which is extremely popular – tickets for these trains typically sell out by early October. The Niles Canyon Railroad has a small but well-maintained collection of historic rail stock.

Part of historic Niles is Mayhew Spring, also known as Mayhew's Sulphur Spring, which was owned by H.A. Meyhew and located 600 ft north of the Niles railroad station. In September 1869, four months after the famous golden spike ceremony at Promontory Summit, Utah, the Central Pacific Railroad completed the transcontinental rail link between Sacramento and the San Francisco Bay, with trains switching at the San Jose junction in the canyon. Central Pacific then built a junction in the valley and opened it in April 1870 as Niles.

Also part of Niles is 1909 Niles Junction built by the Western Pacific Railroad, located at 37.57639°N, -121.97139°W and situated at an elevation of 79 ft.

Irvington District
The Irvington District area, once the town of Irving, has cycled through many name changes over time. In the early 1850s two emancipated black men were traveling with E.L. Beard through California, reputedly in search of a fortune. The former slaves noticed the busy traffic at the crossroads of what is today the "Five Corners" intersection. Although now gone, there were two embarcaderos (water crossings) at this area. One of these crossings had a ferry. Realizing the financial opportunity of the area, the former slaves constructed the first building at the cross roads, a tavern with an inn. This tavern was later known as Dave's Saloon. This corner, today the intersection of Fremont and Washington Boulevards, Union and Bay Streets, is now commonly known as "Five Corners" or Irvington Square. Irvington Square's marker, Irvington Plaza park, is located at 37.52278°N, -121.97167°W. The inn and several of the other original buildings were demolished by the city of Fremont in the early 1980s. In 1871 Washington College, the first industrial educational institution in California was established in Washington township near the crossroads. As a result, the US Postal Service established a post office called Washington Corners at the college in 1870, which became the name of the settlement on the 1878 Alameda County map of Washington Township.

In 1884, realizing the need for a proper town name, local inhabitants selected the name of Irving. The name was chosen in honor of Judge Irving, the local traveling circuit judge of the time. Later, when the railroad came through the area, the published train schedule pamphlets erroneously listed the Irving train depot as "Irvington." The town petitioned the railroad about the error. The railroad company notified the town that it was too costly for them to replace the train schedule pamphlets (over $100,000); and in 1887 following the recommendation, the people of Irving changed the town name to Irvington.

The Irvington district has two main neighborhoods: Irvington Woods and the Irvington Square. The neighborhood is ethnically mixed and is primarily working class. For city planning purposes, the Irvington area was enlarged to encompass most of the south central residential section of Fremont, from Auto Mall Parkway to Mowry Avenue, from I-880 to roughly the BART line (excluding the Central District described below). This Irvington community plan area includes the Sundale neighborhood, the South Sundale neighborhood, 28 Palms, Blacow, and Grimmer subdivisions. The area is served by three high schools: Irvington High School, Robertson High School, and John F. Kennedy High School.

The Irvingtonian period of North American mammals is named for this district due to the fossil sequence excavated here.

Mission San Jose District
At the time of the California Gold Rush, a boom town grew up around the old Mission, to equip and transport 49ers overland to the gold fields. A post office was opened at Mission San Jose in 1850.

The district, like Niles, is surrounded by hills. The hills are higher and steeper than Niles, with the highest points being on the Mission Ridge. Mission San Jose district lies close to the northern two peaks, Mission Peak and Mount Allison. Mission Peak is very distinctive and is one of Fremont's emblems. These peaks go from 2,517 to 2604 ft, taller than Mount Tamalpais, a great height for the San Francisco Bay Area. They see some deep snow occasionally.

Fremont's community college, Ohlone College, is situated one block away from the mission and serves over 12,000 students.

Mission San Jose has the highest concentration of Asian Americans in Fremont – over 50% of the population as of the 2000 census. The local high school is Mission San Jose High School, ranked 67 in the nation by U.S. News & World Report. The median family income for the Mission San Jose area (ZIP code 94539) exceeded $114,595 in 2005. Owing to an influx of professionals and other affluent families seeking access to the top-performing local public schools, Mission San Jose's median home value reached $831,000 in 2006, earning the community a rank of 237 on Forbes magazine's list of the 500 most affluent communities in the United States.

Mission San Jose
Nestled at the base of Fremont's rolling hills is the Mission San José, one of the oldest of the Spanish missions in California, for which this district is named. The church building that exists today is a re-construction (dedicated in 1985 for daily Mass and tours) of the original 1809 adobe church that was destroyed by the 1868 Hayward-fault earthquake. One side of the original mission quadrangle remains and houses a museum. Mission San Jose is located at 37.53306°N, -121.92028°W; and lies at an elevation of 305 ft.

Warm Springs District
The former town of Warm Springs is located on Rancho Agua Caliente and is so named for the springs that are located there. In early times, there was a settlement called Harrisburgh (also, Harrisburg and Peacock's) a short distance east from the small settlement of Warm Springs. A post office opened in Harrisburgh in 1865 and changed its name to Warm Springs in 1885. The name Harrisburgh commemorated Abram Harris, who settled there in 1858. The name Peacock's commemorated George W. Peacock, its first postmaster. The post office name changed to Warmsprings in 1895 and reverted to Warm Springs in 1950.

The Warm Springs district is the southernmost portion of Fremont whose hub is the Warm Springs and Mission Boulevard intersection. It is located at 37.48722°N, -121.92917°W, and lies at an elevation of 62 ft. Warm Springs has attracted the headquarters of many high-tech companies including Nielsen Norman Group, Lam Research, Corsair and Lexar of the US as well as foreign high-tech companies such as Elitegroup Computer Systems, and Asus. The district is also home to blue-collar industry. The San Jose mission is also present.

Warm Springs also serves as commercial center for the mainly residential Mission San Jose district, especially since the construction of Pacific Commons, a large, modern regional shopping center. The Oakland Athletics talked about moving their stadium to this area. Warm Springs was home to one of the SF Bay Area's only two coffee houses to employ baristas who wear bikinis, Your Coffee Cups, a concept that's gained some controversy from Bay Area newspapers and news stations. This controversy led to the eventual closing of the business.

The BART extension to Warm Springs began construction in 2009 and Warm Springs/South Fremont station opened for service on March 25, 2017.

Central district

The central district is surrounded by the Centerville, Niles, Mission San Jose, and Irvington communities. The central district contains retail shopping centers (e.g., the Fremont Hub), the Fremont Bay Area Rapid Transit station, health care centers and Central Park (Lake Elizabeth).

City planners envisioned and have begun to develop a mid-density, pedestrian friendly, transit oriented development, bounded by Mowry Ave, Fremont Blvd, Walnut Ave, and Paseo Padre Pkwy referred to as Downtown Fremont. To support enhanced access, one of the central streets, the Capital Avenue extension to Fremont Blvd, was completed in 2016, as the city pursues its plans for a Downtown Fremont.

Most of Fremont is part of the Laguna Creek Watershed.

North Fremont District
North Fremont is a primarily residential district surrounded by Union City, Centerville District, Newark, and Coyote Hills Regional Park. It is a growing community that includes the Ardenwood neighborhood, the Lakes and Birds neighborhood, and the Northgate neighborhood. It is the site of the Ardenwood Historic Farm, which has the George Washington Patterson House as one of its highlights, and the Ardenwood Technology Park. A 99 Ranch Market is one of many Asian businesses in the North Fremont District. Thornton Junior High School and American High School, which are both physically located in the enlarged Centerville District, also serve as the junior high and high school, respectively, for this community.

South Fremont District
South Fremont is a primarily industrial district, east of Interstate 880 and west of Interstate 680, south of Auto Mall Parkway and north of Brown Rd. The area overlaps with Warm Springs, with which it shares the eponymous BART station. The composition of the area will change, because thousands of residential units were under construction as of 2016. It is sandwiched between the Irvington and Warm Springs community plan areas. It is noted as the site of the Tesla Factory as well as the site of the Warm Springs / South Fremont BART station. In 2022, a pedestrian bridge was built from the BART station to Lopes Court. It cost $41 million.

Bayside Industrial District
Bayside Industrial is a primarily industrial and commercial district, west of Interstate 880 between Newark and Milpitas.

Hill Area District
Hill Area is an open land district that forms the eastern edge of Fremont. It is the site of Mission Peak.

Climate
Fremont has a warm-summer Mediterranean climate (Köppen: Csb) typical of the San Francisco Bay Area. This climate features warm, dry summers and cool, wet winters. Like nearby San Jose, precipitation is fairly low (about 17 inches per year) because the city lies in the rain shadow of the Santa Cruz Mountains to the west. The highest temperature recorded was 110 °F on September 6, 2022. The lowest temperature recorded was 21 °F on December 23, 1990.

2020
According to the 2020 census estimate, the median income for a household in the city is $142,374. Males have a median household income of $59,274 versus $40,625 for females. The per capita income for the city was $31,411. About 4.5% of the population were below the poverty line, including 5.9% of those under age 18 and 6.2% of those age 65 or over.

2010

The 2010 United States Census reported that Fremont had a population of 214,089. The population density was 2,443.7 PD/sqmi.

The Census reported that 212,438 people (99.2% of the population) lived in households, 969 (0.5%) lived in non-institutionalized group quarters, and 682 (0.3%) were institutionalized.

There were 71,004 households, out of which 31,070 (43.8%) had children under the age of 18 living in them, 45,121 (63.5%) were opposite-sex married couples living together, 7,070 (10.0%) had a female householder with no husband present, 3,382 (4.8%) had a male householder with no wife present. There were 2,779 (3.9%) unmarried opposite-sex partnerships, and 444 (0.6%) same-sex married couples or partnerships. 11,576 households (16.3%) were made up of individuals, and 3,697 (5.2%) had someone living alone who was 65 years of age or older. The average household size was 2.99. There were 55,573 families (78.3% of all households); the average family size was 3.36.

The population was spread out, with 53,216 people (24.9%) under the age of 18, 15,610 people (7.3%) aged 18 to 24, 66,944 people (31.3%) aged 25 to 44, 56,510 people (26.4%) aged 45 to 64, and 21,809 people (10.2%) who were 65 years of age or older. The median age was 36.8 years. For every 100 females, there were 98.9 males. For every 100 females age 18 and over, there were 96.4 males.

There were 73,989 housing units at an average density of 844.5 /mi2, of which 71,004 were occupied, of which 44,463 (62.6%) were owner-occupied, and 26,541 (37.4%) were occupied by renters. The homeowner vacancy rate was 1.3%; the rental vacancy rate was 4.5%. 136,606 people (63.8% of the population) lived in owner-occupied housing units and 75,832 people (35.4%) lived in rental housing units.

Fremont has a large Deaf community, in large part because it is home of the Northern California campus of the California School for the Deaf. The school district is called the Fremont Unified School District which also serves parts of Union City and Hayward.

Race and ethnicity
As of 2010, more than half the residents of Fremont were of Asian ancestry, with large populations of Chinese, Asian Indians, and Filipinos.

The racial makeup of Fremont was:

 * 108,332 (50.6%) Asian (consisting of 18.1% Indian, 17.8% Chinese, 6.7% Filipino, 2.5% Vietnamese, 1.8% Korean, 1.0% Pakistani, 0.8% Japanese, 0.6% Burmese)
 * 70,320 (32.8%) White, Non-Hispanic Whites were 26.5% of the population in 2010, down from 85.4% in 1970.
 * 31,698 (14.8%) Hispanic or Latino of any race. (consisting of 11.0% Mexican, 0.6% Puerto Rican, 0.5% Salvadoran).
 * 13,605 (6.4%) from other races,
 * 12,584 (5.9%) from two or more races
 * 7,103 (3.3%) African American,
 * 1,169 (0.5%) Pacific Islander,
 * 976 (0.5%) Native American,

Due in large part to a substantial influx of Afghans granted asylum in the United States following the 1979 invasion of Afghanistan by the Soviet Union, Fremont is the home to the largest concentration of Afghan Americans in the United States. Judith Miller of City Journal wrote that unlike many ethnic groups, the Afghans in Fremont have few political representatives at various levels and an insular focus. This concentration is noted in Khaled Hosseini's 2003 novel Kite Runner.

Fremont and nearby Union City have fairly large numbers of Pacific Islanders, Cubans and Puerto Ricans, Spanish and Portuguese, and a small number of American Indians.

Economy
Companies headquartered in Fremont include Antec Inc, Corsair Gaming, Electronics for Imaging, Ikanos Communications, Lam Research, Seagate Technology, Fremont Bank, Nielsen Norman Group, Oplink Communications, SYNNEX, S3 Graphics, Tailored Brands and DCKAP.

Top employers
According to the city's June 2022 Annual Comprehensive Financial Report, the top employers in the city are:

Culture and recreation
The City of Fremont has been a Tree City USA since 1996. There are approximately 55,000 trees in city parks, streets, and landscaped boulevard areas. The city operates the Olive Hyde Art Gallery, adjacent to Mission San Jose, which has featured Bay Area artists such as Wendy Yoshimura, the California Society of Printmakers and the Etsy collective. The public gallery is housed in a former home of Olive Hyde, a descendant of early San Francisco Mayor George Hyde.

Other cultural, historical, or scientific landmarks include: Fremont Central Park and Lake Elizabeth, Ardenwood Historic Farm, California Nursery Historical Park, Don Edwards National Wildlife Refuge, Mission Peak Regional Preserve, Niles Essanay Silent Film Museum, Washington Township Museum of Local History, Quarry Lakes Regional Recreation Area, Shinn Park and Arboretum, and Coyote Hills Regional Park.

Media
Founded in 2002, the Tri-City Voice serves Fremont and the nearby cities of Union City and Newark. The weekly is based in the Fremont, and publishes the city's legal notices.

Government
An elected mayor heads Fremont city government for a four-year term. The mayor chairs the city council, which has four elected council members in addition to the mayor. Two new seats have been added to the council beginning in 2018, for a total of seven seats when district-based elections are phased in. The council adopts the city's budget, and decides major policies. The city council appoints a city manager and city attorney. The city manager hires city staff, and manages day-to-day business. Advisory bodies work with the city council on some issues, to facilitate the council's final decisions. The mayor appoints advisory body members, subject to the approval of a majority of the council. Most members serve four-year terms of office without pay, with the exception of planning commissioners.

The City of Fremont directly provides services related to public safety, land use regulation, infrastructure maintenance, parks and recreation, and local social services. To provide these services, the city government is organized into 22 departments, from Animal Services to Transportation Engineering.

According to a 2009 financial report, city revenues were $280 million, expenditures $200 million, assets $1,200 million, cash and investments $340 million, and liabilities $260 million. As of 2015, the annual budget was $160 million and the city had 800 employees.

The city council has adopted a balanced budget by July 1 of each year. Budget problems have in some past years involved cuts in services, reductions in city staffing and wage concessions by labor unions.

Special districts provide water and sewer services for the city: Alameda County Water District and Union Sanitary District. A private contractor, Allied Waste, provides garbage collection and recycling services to the city.

BoxART! Program: The City of Fremont boxART ! program transforms Fremont's traffic signal control boxes with compelling and creative imagery.

Grand Jury investigation of record-keeping
A Grand Jury in 2015 found that the city government did not comply with state law on public records, by deleting most emails after 30 days instead of the required two years. All emails were labeled automatically as "unsaved drafts" unless designated manually for retention. The city did not keep any record of councilmember emails, which used fremont.gov addresses and were relayed on to councilmembers' private email accounts. Though city officials held that automatic deletion would reduce data storage costs, the Grand Jury determined that the cost of complying with the state law would not be significant.

District-based elections
The city will phase in district-based instead of at-large elections for all but one seat on the city council, beginning in November 2018. Two new seats will be added, from five seats to seven. Six of the seats will require residence inside a district, while the seat held by the mayor will remain at large. The council chose the new district boundaries in June 2017, a controversial vote that drew accusations of gerrymandering to favor two of the incumbents.

The districting was forced by the threat of a legal action from a group claiming that Latino minorities comprising 14 percent of the population had not been adequately represented. Few or no Latinos were elected to the council during 1956–2017. Some claimed that the results of precinct voting may have been polarized along racial lines.

Politics
According to the California Secretary of State, as of February 10, 2019, Fremont has 104,650 registered voters. Of those, 46,840 (44.8%) are registered Democrats, 13,989 (13.4%) are registered Republicans, and 40,161 (38.4%) have declined to state a political party.

Primary and secondary schools
The Fremont Unified School District has five high schools for grades 9–12: American, Irvington, Kennedy, Mission San Jose and Washington. The 5,000 seat Tak Fudenna Stadium serves all five high schools as a venue for football, track, soccer and high school graduation ceremonies. These five high schools, along with James Logan High School in Union City and Newark Memorial High School in Newark, make up the Mission Valley Athletic League (M.V.A.L.).

The district has a continuation high school (Robertson); two independent study programs (Vista and COIL); an adult school; five middle schools for grades 6–8 (Centerville, Hopkins, Horner, Thornton and Walters); and 29 elementary schools, including Glenmoor Elementary.(K-6). The district operates the Mission Valley Regional Occupational Program jointly with Newark and New Haven Unified School Districts.

For the year 2019, William Hopkins Junior High, Mission San Jose High, John F. Kennedy High, and American High all received the California Distinguished Schools Award, administered by the California Department of Education.

Fremont Christian School and Averroes High School in Fremont are not part of FUSD. California School for the Deaf, Fremont serves Northern California and shares a campus with the statewide California School for the Blind.

Colleges and universities
The Ohlone Community College District operates Ohlone College in Fremont, and a smaller campus in Newark. The University of Phoenix Bay Area Campus and San Francisco Bay University offers undergraduate and graduate programs in technology and management areas and is known for disrupting higher education and offering low cost degree programs.

Public libraries
The Alameda County Library is headquartered in Fremont. The Fremont Main Library is the largest branch with the highest circulation of the Alameda County Library, and shares its building with the Alameda County Library Administration. It has the Maurice Marks Center for Local and California History, and the Fukaya public meeting room. Alameda County Library has other branch libraries in Centerville, Irvington and Niles.

Transportation
Fremont is served by Interstate 880 (Nimitz Freeway) and Interstate 680 (Sinclair Freeway). Though they do not intersect, they are connected in the Warm Springs district via a very busy one-mile segment of Mission Boulevard which is SR 262. In addition, it is served by SR 84 and the segment of Mission Boulevard which is SR 238. The city is the eastern terminus of the Dumbarton Bridge.

Elevated sound levels exist along Interstate 880; Caltrans and the city have sought to mitigate sound levels by constructing noise barriers.

Regional rail transportation is provided by BART and the Altamont Corridor Express (ACE). Fremont's BART station once served as the southernmost terminus for the BART system; a 5.4 mi BART extension to the Warm Springs / South Fremont station opened on March 25, 2017. A southward BART extension into Santa Clara county and the Milpitas and Berryessa/North San José stations opened on June 13, 2020; a further BART extension to downtown San Jose is in the planning stages. The Fremont-Centerville station provides a stopping point for ACE service, which travels from Stockton to San Jose, as well as for Amtrak's Capitol Corridor service. Bus service is provided by AC Transit locally.

Future rail
Caltrain is undertaking environmental and engineering review for a planned Dumbarton Rail Corridor between the Peninsula and Alameda County. It would add Caltrain stations to Union City, Fremont-Centerville, Newark, and Menlo Park/East Palo Alto.

Notable people

 * John Buttencourt Avila, father of sweet potato industry, worked in Niles District during the 1880s
 * Bud Harrelson, Major League Baseball player and coach
 * DeAnna Bennett, mixed martial artist
 * Karen Chen, figure skater, US National Champion 2017
 * Rosalie Chiang, actress
 * Emilio Castillo, founding member of Tower of Power
 * Vinod Dham, father of the Intel Pentium
 * Shawon Dunston, Major League Baseball infielder
 * Dina Eastwood, ex-wife of actor/director Clint Eastwood
 * Dennis Eckersley, Major League Baseball Hall of Famer, pitched for several MLB teams; Washington High School graduate
 * Harry Edwards, sociologist and civil rights activist; worked with San Francisco 49ers and Golden State Warriors, professor at UC-Berkeley; resides in Fremont
 * Yousef Erakat, YouTube personality
 * Qader Eshpari, Afghan musical artist
 * Robb Flynn, musician
 * Tony Gemignani, World Champion Pizza Maker.
 * Pragathi Guruprasad, Indian playback singer
 * MC Hammer, musical artist
 * Don Hertzfeldt, animator
 * Ariel Hsing, Olympic table tennis player
 * Khaled Hosseini, award-winning Afghan author
 * Karin Ireland, author
 * Dominic Kinnear, professional soccer player and coach
 * Steven Kwan - MLB player
 * Steve Lewis, sprinter, Olympic gold medalist
 * Christine Liang, president and founder of ASI Corp.
 * Allan Haines Loughead, co-founder of Lockheed Corporation
 * Mikh McKinney, basketball player
 * Justin Medlock, NFL placekicker
 * Helen Wills Moody, tennis pro, won 31 Grand Slam championships
 * Lamond Murray, John F. Kennedy High School graduate, UC-Berkeley and NBA basketball player
 * Sammy Obeid, comedian, performed 1,000 nights of comedy in a row, a world record
 * Julie Pinson, actress
 * Gary Plummer, football player
 * Rome Ramirez, of Sublime with Rome
 * Randy Ready, John F. Kennedy High graduate; Major League Baseball player 1983–1995
 * Dick Ruthven, Irvington High graduate, starting pitcher for 1980 World Series champion Philadelphia Phillies
 * Ryan Sinn, musician
 * Sid Sriram, Indian playback singer
 * Ray Stevens, pro wrestler
 * Cal Stevenson (born 1996), baseball outfielder for the San Francisco Giants
 * Kevin Tan, Olympic gymnast
 * Meagan Tandy, model and actress
 * Pat Tillman, football player who left his NFL career to enlist in the U.S. Army
 * Robert Turbin, NFL running back
 * Kevin Turner, Mission San Jose High School graduate, linebacker in NFL for several teams
 * Bill Walsh, coach of NFL's San Francisco 49ers in Hall of Fame; coached for Washington High School
 * Len Wiseman, film director
 * John Woodcock, NFL defensive lineman
 * Kristi Yamaguchi, figure skater, Olympic gold medalist

Sister cities
Fremont was formerly a sister city to Elizabeth, South Australia until Elizabeth merged with Munno Para to form the City of Playford in 1997. Currently, Fremont is currently twinned with the following cities:

title: Fremont, California


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Volumetric heat capacity

The volumetric heat capacity of a material is the heat capacity of a sample of the substance divided by the volume of the sample. It is the amount of energy that must be added, in the form of heat, to one unit of volume of the material in order to cause an increase of one unit in its temperature. The SI unit of volumetric heat capacity is joule per kelvin per cubic meter, J⋅K−1⋅m−3.

The volumetric heat capacity can also be expressed as the specific heat capacity (heat capacity per unit of mass, in J⋅K−1⋅kg−1) times the density of the substance (in kg/L, or g/mL).

This quantity may be convenient for materials that are commonly measured by volume rather than mass, as is often the case in engineering and other technical disciplines. The volumetric heat capacity often varies with temperature, and is different for each state of matter. While the substance is undergoing a phase transition, such as melting or boiling, its volumetric heat capacity is technically infinite, because the heat goes into changing its state rather than raising its temperature.

The volumetric heat capacity of a substance, especially a gas, may be significantly higher when it is allowed to expand as it is heated (volumetric heat capacity at constant pressure) than when is heated in a closed vessel that prevents expansion (volumetric heat capacity at constant volume).

If the amount of substance is taken to be the number of moles in the sample (as is sometimes done in chemistry), one gets the molar heat capacity (whose SI unit is joule per kelvin per mole, J⋅K−1⋅mol−1).

Definition
The volumetric heat capacity is defined as
 * $$s(T) = \frac{C(T)}{V(T)} = \frac{1}{V(T)} \lim_{\Delta T \to 0}\frac{\Delta Q(T)}{\Delta T}$$

where $$V(T)$$ is the volume of the sample at temperature $$T$$, and $$\Delta Q(T)$$ is the amount of heat energy needed to raise the temperature of the sample from $$T$$ to $$T + \Delta T$$. This parameter is an intensive property of the substance.

Since both the heat capacity of an object and its volume may vary with temperature, in unrelated ways, the volumetric heat capacity is usually a function of temperature too. It is equal to the specific heat $$c(T)$$ of the substance times its density (mass per volume) $$\rho(T)$$, both measured at the temperature $$T$$. Its SI unit is joule per kelvin per cubic meter (J⋅K−1⋅m−3).

This quantity is used almost exclusively for liquids and solids, since for gases it may be confused with the "specific heat capacity at constant volume", which generally has very different values. International standards now recommend that "specific heat capacity" always refer to capacity per unit of mass. Therefore, the word "volumetric" should always be used for this quantity.

History
Dulong and Petit predicted in 1818 that the product of solid substance density and specific heat capacity (ρcp) would be constant for all solids. This amounted to a prediction that volumetric heat capacity in solids would be constant. In 1819 they found that volumetric heat capacities were not quite constant, but that the most constant quantity was the heat capacity of solids adjusted by the presumed weight of the atoms of the substance, as defined by Dalton (the Dulong–Petit law). This quantity was proportional to the heat capacity per atomic weight (or per molar mass), which suggested that it is the heat capacity per atom (not per unit of volume) which is closest to being a constant in solids.

Eventually it became clear that heat capacities per particle for all substances in all states are the same, to within a factor of two, so long as temperatures are not in the cryogenic range.

Typical values
The volumetric heat capacity of solid materials at room temperatures and above varies widely, from about 1.2 MJ⋅K−1⋅m−3 (for example bismuth ) to 3.4 MJ⋅K−1⋅m−3 (for example iron ). This is mostly due to differences in the physical size of atoms. Atoms vary greatly in density, with the heaviest often being more dense, and thus are closer to taking up the same average volume in solids than their mass alone would predict. If all atoms were the same size, molar and volumetric heat capacity would be proportional and differ by only a single constant reflecting ratios of the atomic molar volume of materials (their atomic density). An additional factor for all types of specific heat capacities (including molar specific heats) then further reflects degrees of freedom available to the atoms composing the substance, at various temperatures.

For most liquids, the volumetric heat capacity is narrower, for example octane at 1.64 MJ⋅K−1⋅m−3 or ethanol at 1.9. This reflects the modest loss of degrees of freedom for particles in liquids as compared with solids.

However, water has a very high volumetric heat capacity, at 4.18 MJ⋅K−1⋅m−3, and ammonia is also fairly high: 3.3 MJ⋅K−1⋅m−3.

For gases at room temperature, the range of volumetric heat capacities per atom (not per molecule) only varies between different gases by a small factor less than two, because every ideal gas has the same molar volume. Thus, each gas molecule occupies the same mean volume in all ideal gases, regardless of the type of gas (see kinetic theory). This fact gives each gas molecule the same effective "volume" in all ideal gases (although this volume/molecule in gases is far larger than molecules occupy on average in solids or liquids). Thus, in the limit of ideal gas behavior (which many gases approximate except at low temperatures and/or extremes of pressure) this property reduces differences in gas volumetric heat capacity to simple differences in the heat capacities of individual molecules. As noted, these differ by a factor depending on the degrees of freedom available to particles within the molecules.

Volumetric heat capacity of gases
Large complex gas molecules may have high heat capacities per mole (of molecules), but their heat capacities per mole of atoms are very similar to those of liquids and solids, again differing by less than a factor of two per mole of atoms. This factor of two represents vibrational degrees of freedom available in solids vs. gas molecules of various complexities.

In monatomic gases (like argon) at room temperature and constant volume, volumetric heat capacities are all very close to 0.5 kJ⋅K−1⋅m−3, which is the same as the theoretical value of $3⁄2$RT per kelvin per mole of gas molecules (where R is the gas constant and T is temperature). As noted, the much lower values for gas heat capacity in terms of volume as compared with solids (although more comparable per mole, see below) results mostly from the fact that gases under standard conditions consist of mostly empty space (about 99.9% of volume), which is not filled by the atomic volumes of the atoms in the gas. Since the molar volume of gases is very roughly 1000 times that of solids and liquids, this results in a factor of about 1000 loss in volumetric heat capacity for gases, as compared with liquids and solids. Monatomic gas heat capacities per atom (not per molecule) are decreased by a factor of 2 with regard to solids, due to loss of half of the potential degrees of freedom per atom for storing energy in a monatomic gas, as compared with regard to an ideal solid. There is some difference in the heat capacity of monatomic vs. polyatomic gasses, and also gas heat capacity is temperature-dependent in many ranges for polyatomic gases; these factors act to modestly (up to the discussed factor of 2) increase heat capacity per atom in polyatomic gases, as compared with monatomic gases. Volumetric heat capacities in polyatomic gases vary widely, however, since they are dependent largely on the number of atoms per molecule in the gas, which in turn determines the total number of atoms per volume in the gas.

The volumetric heat capacity is defined as having SI units of J/(m3⋅K). It can also be described in Imperial units of BTU/(ft3⋅°F).

Volumetric heat capacity of solids
Since the bulk density of a solid chemical element is strongly related to its molar mass (usually about 3R per mole, as noted above), there exists noticeable inverse correlation between a solid's density and its specific heat capacity on a per-mass basis. This is due to a very approximate tendency of atoms of most elements to be about the same size, despite much wider variations in density and atomic weight. These two factors (constancy of atomic volume and constancy of mole-specific heat capacity) result in a good correlation between the volume of any given solid chemical element and its total heat capacity. Another way of stating this, is that the volume-specific heat capacity (volumetric heat capacity) of solid elements is roughly a constant. The molar volume of solid elements is very roughly constant, and (even more reliably) so also is the molar heat capacity for most solid substances. These two factors determine the volumetric heat capacity, which as a bulk property may be striking in consistency. For example, the element uranium is a metal which has a density almost 36 times that of the metal lithium, but uranium's volumetric heat capacity is only about 20% larger than lithium's.

Since the volume-specific corollary of the Dulong–Petit specific heat capacity relationship requires that atoms of all elements take up (on average) the same volume in solids, there are many departures from it, with most of these due to variations in atomic size. For instance, arsenic, which is only 14.5% less dense than antimony, has nearly 59% more specific heat capacity on a mass basis. In other words; even though an ingot of arsenic is only about 17% larger than an antimony one of the same mass, it absorbs about 59% more heat for a given temperature rise. The heat capacity ratios of the two substances closely follows the ratios of their molar volumes (the ratios of numbers of atoms in the same volume of each substance); the departure from the correlation to simple volumes in this case is due to lighter arsenic atoms being significantly more closely packed than antimony atoms, instead of similar size. In other words, similar-sized atoms would cause a mole of arsenic to be 63% larger than a mole of antimony, with a correspondingly lower density, allowing its volume to more closely mirror its heat capacity behavior.

Volumetric heat capacity of liquids
The volumetric heat capacity of liquids could be measured from the thermal conductivity and thermal diffusivity correlation. The volumetric heat capacity of liquids could be directly obtained during thermal conductivity analysis using thermal conductivity analyzers that use techniques like the transient plane source method.

Thermal inertia
Thermal inertia is a term commonly used to describe the observed delays in a body's temperature response during heat transfers. The phenomenon exists because of a body's ability to both store and transport heat relative to its environment. Since the configuration of system components and mix of heat transfer mechanisms (e.g. conduction, convection, radiation, phase change) varies substantially between instances, there is no generally applicable mathematical definition for thermal inertia. The phenomenon occurs in conjunction with a material's or a transport medium's heat transfer properties. A larger thermal storage capacity typically yields a more sluggish temperature response.

A system containing one or more components with large volumetric heat capacity indicates that dynamic, or transient, effects must be considered when modelling system behavior. Steady-state calculations, many of which produce valid estimates of equilibrium heat flows and temperatures without an accounting for thermal inertia, nevertheless yield no information on the pace of changes between equilibrium states. Response times for complex systems can be evaluated with detailed numerical simulation, or a thermal time constant estimated from a lumped system analysis. A higher value of volumetric heat capacity generally means a longer time for the system to reach equilibrium.

Analogies of thermal inertia to the inertial behaviors observed in other disciplines of engineering and physics can sometimes be used with caution. In building design, thermal inertia is also known as the thermal flywheel effect, and a thermal mass can produce a delay between diurnal heat flow and temperature which is similar to the delay between current and voltage in an AC-driven RC circuit. Thermal inertia is less directly comparable to the mass-and-velocity term used in mechanics, where inertia restricts the acceleration of an object. In a similar way, thermal inertia is a measure of the thermal mass and the velocity of the thermal wave which controls the surface temperature of a material.

Thermal effusivity
For a semi-infinite rigid body where heat transfer is dominated by the diffusive process of conduction only, the thermal inertia response at a surface can be approximated from the material's thermal effusivity (e). It is defined as the square root of the product of the material's bulk thermal conductivity and volumetric heat capacity, where the latter is the product of density and specific heat capacity:
 * $$e = \sqrt{k \rho c}$$

Thermal effusivity has units of a heat transfer coefficient multiplied by square root of time: When a constant flow of heat is abruptly imposed upon a surface, e performs nearly the same role in limiting the surfaces initial dynamic "thermal inertia" response ( Udyn ≈ e ⋅ t −1/2 ) as the rigid body's usual heat transfer coefficient (U) plays in determining the final static surface temperature.
 * $$k$$ is thermal conductivity, with unit W⋅m−1⋅K−1
 * $$\rho$$ is density, with unit kg⋅m−3
 * $$c$$ is specific heat capacity, with unit J⋅kg−1⋅K−1
 * SI units of W⋅m−2⋅K−1⋅s1/2 or J⋅m−2⋅K−1⋅s−1/2.
 * Non-SI units of kieffers: Cal⋅cm−2⋅K−1⋅s−1/2, are also used informally in older references.

Constant volume and constant pressure
For gases it is necessary to distinguish between volumetric heat capacity at constant volume and volumetric heat capacity at constant pressure, which is always larger due to the pressure–volume work done as a gas expands during heating at constant pressure (thus absorbing heat which is converted to work). The distinctions between constant-volume and constant-pressure heat capacities are also made in various types of specific heat capacity (the latter meaning either mass-specific or mole-specific heat capacity).

title: Volumetric heat capacity