Maciej ; Wojtczak
email: maciej.wojtczak@plodz.pl

Aneta Antczak

Małgorzata Przybyt

The use of ionic chromatography in determining the contamination of apple juice by lactic acid

Keywords: Chromatographic analysis, Screening -biosensor Additives/Contaminants: Process contaminants Food Types: Fruit juices lactic acid, lactic fermentation, ion chromatography, apple juice

In this study, high performance anion exchange chromatography (HPAEC) with conductometric detection was used for determining lactic acid content of apple juice subjected to fermentation with the strains of Lactobacillus brevis and Lactobacillus plantarum, obtained from a collection, at 20 and 30 0 C. At the same time, lactate content was determined by means of enzymatic tests and biosensors. Lactic acid concentrations determined by the chromatographic method are similar to those obtained during analysis by enzymatic tests. However, acid concentrations determined by means of biosensors substantially diverge from these results.

Introduction

Lactic fermentation is one of the key processes in the food industry. It helps to provide products with the right aroma, taste and consistency, increases their shelf life, improves their nutritive value, and sometimes also contributes to probiotic properties of the final product (Feord 2002). Apart from the food industry, it is also widely used in the chemical, pharmaceutical, cosmetic, leather, and textile industries [START_REF] Rojan | Statistical optimization of simultaneous saccharification and L(+)-lactic acid fermentation from cassava bagasse using mixed culture of lactobacilli by response surface methodology[END_REF][START_REF] Zhang | Production of lactic acid from renewable materials by Rhizopus fungi[END_REF]. Lactic fermentation is a process of anaerobic conversion of saccharides to lactic acid. It is one of the ways of obtaining the energy necessary for maintaining the life processes of microorganisms under anaerobic conditions. Lactic fermentation can be either homofermentative, where two molecules of lactic acid are formed from one molecule of glucose [START_REF] Li | An electrokinetic bioreactor: using direct electric current for enhanced lactic acid fermentation and product recovery[END_REF], or heterofermentative, where one molecule of glucose is converted to one molecule of lactic acid, one molecule of acetic acid (under aerobic conditions) or one molecule of ethanol (under anaerobic conditions) and one molecule of carbon dioxide [START_REF] Kandler | Carbohydrate metabolizm in lactic acid bacteria[END_REF].

There are two optically active stereoisomers of lactic acid: isomer L(+) and isomer D(-). Lactic acid may be produced by microbiological fermentation, which leads to either L-or Dlactic acid or racemate, depending on microorganisms, substrates and fermentation conditions employed in the production process. Renewable resources including sugars, starch and lignocellulose are abundant substrates for fermentative production. A racemate of both isomers is produced by chemical synthesis. The most commonly used synthetic method for chemical production of lactic acid is the hydrolysis of lactonitrile derived from acetaldehyde and hydrogen cyanide, which are produced by petrochemical process [START_REF] Oh | Lactic acid production from agricultural resources as cheap raw materials[END_REF][START_REF] Reddy | Amylolytic bacterial lactic acid fermentation -A review[END_REF][START_REF] Zhang | Production of lactic acid from renewable materials by Rhizopus fungi[END_REF].

Lactic acid can be produced using bacteria or fungi such as Rhizopus oryzae in submerged culture. Lactic acid producing bacteria (LAB) have received wide interest because of their high growth rate and product yield [START_REF] Chopin | Organization and regulation of genes for amino acid biosynthesis in lactic acid bacteria[END_REF][START_REF] Zhang | Production of lactic acid from renewable materials by Rhizopus fungi[END_REF]. LAB are generally mesophilic but they can grow at temperatures as low as 5°C or as high as 45°C. Majority of strains of LAB grow at pH 4,0 -4,5, but some are active at pH 3,2 and others at pH 9,6 (Caplice & Fitzerald, 1999).

High production of lactic acid is normally achieved by selecting suitable microbial strains in the process of fermentation. Strains of Lactobacillus can be homofermentative or heterofermentative. However, the strains of Lactobacillus brevis used in this study belong to a group of lactic acid bacteria obligately heterofermentative which ferment hexose in the pentose phosphoketolaze pathway. Lactobacillus plantarum is a group of facultatively heterofermentative microorganisms that metabolize hexose in the Embden-Meyerhof-Parnas pathway and pentose and some other substrates in the pentose phosphoketolaze pathway [START_REF] Stiles | Lactic acid bacteria of foods and their current taxonomy[END_REF]Libudzisz et al. 2008). Among lactic fermentation bacteria, typical homofermentative species include:

Lactobacillus delbrueckii, L. casei, L. acidophilus, L. bulgaricus [START_REF] Hickey | Transport and Metabolism of Lactose, Glucose, and Galactose in Homofermentative Lactobacilli[END_REF], Vodnar & Socaciu, 2008). While L. delbrueckii uses glucose, fructose, and sucrose for the production of lactic acid by homofermentation, the other bacteria additionally use lactose and galactose [START_REF] Chang | Homofermentative Production of D-or L-Lactate in Metabolically Engineered Escherichia coli RR1[END_REF], Vodnar & Socaciu, 2008). Lactic acid bacteria are used in the food industry for several reasons. Their growth lowers both the carbohydrate content of the foods that they ferment, and the pH due to lactic acid production. It is this acidification process which is one of the most desirable side-effects of their growth. The pH may drop to as low as 4.0, low enough to inhibit the growth of most other microorganisms including the most common human pathogens, thus allowing these foods prolonged shelf life (Libudzisz et al. 2008). The desirable characteristics of industrial microorganisms are their ability to rapidly and completely ferment cheap raw materials, requiring minimal amount of nitrogenous substances, providing high yields of preferred stereo specific lactic acid under conditions of low pH and high temperature production of low amounts of cell mass and negligible amounts of other by-products [START_REF] Narayanan | L (+) lactic acid fermentation and its product polymerization[END_REF].

Too high a content of lactic acid can be critical in the fruit and vegetable industry, and in particular in the juice industry, where a major problem for fruit juice manufacturers is product spoilage by lactic acid bacteria which cause undesirable fermentation processes [START_REF] Trifirò | Use of ion chromatography for monitoring microbial spoilage in the fruit juice industry[END_REF].

Their presence is often detected after 4-5 days or later, which leads to contamination of a large volume of juice at various stages of the manufacturing process. This in turn may result in decreasing the quality of the final product or even in rendering it undrinkable and necessitating its disposal. Thus, the bacteria cause immense financial losses in manufacturing plants. The Code of Practice of AIJN (European Fruit Juice Association) established the maximum permissible concentration of lactates in fruit juices, which is 0.5 g l -1 [START_REF] Trifirò | Use of ion chromatography for monitoring microbial spoilage in the fruit juice industry[END_REF].

The determination of lactic acid content in fruit juices may be conducted by a variety of methods. The most selective and sensitive methods are enzymatic tests, which, however, involve a substantial amount of work, as it is necessary to perform a separate analysis for every measured component, and the measurement itself requires a tight time schedule to be observed painstakingly [START_REF] Cunha | HPLC/UV determination of organic acids in Feord J.: Lactic acid bacteria in a changing legislative environment[END_REF][START_REF] Trifirò | Use of ion chromatography for monitoring microbial spoilage in the fruit juice industry[END_REF]. Analysis of lactic acid content may be also conducted by the chromatographic method using different separation techniques and detectors like HPLC/UV-VIS (Vodnar & Socaciu C. 2008) or with the use of biosensors [START_REF] Przybyt | Zastosowanie biosensorów do oznaczania mleczanów w owocowych sokach komercyjnych i koncentratach, śywność[END_REF]. However, recent studies have shown the HPLC method with UV-VIS detection to be inexact as it results in significant differences in the determined concentrations as compared to results obtained by means of biosensors, which in most cases substantially overstated the result largely due to insufficient separation of the lactic acid peak (Vodnar & Socaciu, 2008).

Therefore, the authors decided to use high performance anion exchange chromatography with conductometric detection for determining lactic acid concentration. Ion chromatography is an instrumental technique used for the separation and determination of organic and inorganic anions and cations and other substances after their prior conversion to the ion form. Its advantages include: quick analysis, efficiency, high sensitivity and very good repeatability of the results. Furthermore, the short measurement time and small samples required for analysis make it possible to detect and quantify an analyte at the level of µg l -1 . Using a single analytical technique, it is possible to obtain complete information on the ion composition of the analyzed sample. (Fritz, 2000[START_REF] Michalski | Chromatografia jonowa, podstawy i zastosowania; Wydawnictwa Naukowo-Techniczne[END_REF].

Materials and methods

The material for analysis was apple juice containing 11.2% of dry matter prepared by diluting concentrated apple juice containing 68.9% of dry matter. The concentrate was supplied by the company VINKON S.A., and the study was conducted as part of the collective research project Quali-Juice "Quality assurance and development of an early warning system for microbial spoilage for the European fruit juice industry".

Apple juice was subjected to fermentation with the strains of Lactobacillus plantarum (ŁOCK 0864) and Lactobacillus brevis (ŁOCK 0845). 699 mL of dissolved and sterilized juice was inoculated with 1 mL of bacteria suspension. The study consisted of measurement of changes in the concentration of lactic acid by the high performance anion exchange chromatography method with conductometric detection. In all the assays, for comparative reasons, the concentration of L-lactic acid anions was quantified by means of biosensors: Biosen C Line sport (EKF, Germany) and LactatProfi 3000 (ABT, Germany) as well as enzymatic tests Megazyme (Ireland), which were also used for determining the concentration of D-lactic acid anions. Apple juice fermentation was conducted at two temperatures: 20 and 30 0 C. The samples were taken at 0, 24, 48, 72, 96 and 168 hours of the fermentation process. In order to stop the fermentation each sample was immediately frozen and stored until the moment of analyzing.

For enzymatic assay (spectrophotometric) of lactate 1 mL of sample was added to 100 mg of polyvinylpyrrolidone (PVPP), shaked vigorously, left for 5 minutes and then centrifuged at 14 000 rpm for 15 minutes. The assay was done according to the procedure given by the producer of kits.

Each assay was triplicated. The absorbance was measured at 340 nm in disposable PMMA Plastibrand® cuvettes (Sigma, Germany) with UV spectrophotometer Nicolet Evolution 300 from Thermo Electron Corporation (MA, USA).

The assay of lactate concentration with the use of biosensors was done according to the producer manual with standards and buffers purchased from them.

Chromatographic analysis was performed with an ion chromatograph DIONEX ICS-3000 with a conductivity detector. Separation was conducted with the use of the column Ion Pac AS 11-HC 4x250mm and a conductivity suppressor ASRS-ULTRA II 4mm produced by the company Juice samples were diluted with distilled water (18MΩ) at a ratio of 1:10, and before injection they were filtered through membrane filters with a pore diameter of 0.45 µm.

The separation of acids contained in apple juices was conducted in the following conditions: flow:

1.5 ml min -1 ; column temperature: 30 0 C; injection: 10µL. Gradient separation was used with the following eluents being used as the mobile phase: 5 mM NaOH (eluent 1), 100 mM NaOH (eluent 2) and distilled water 18MΩ (eluent 3) according to the following time and composition program (eluent 1, 2 and 3 were expressed as percent [v/v]): -5 to 0 min, 20, 0 and 80; 0 to 17 min, 90, 0 and 10; 17 to 21 min, 0, 15 and 95; 21 to 30 min, 0, 30 and 70; 30 to 31 min, 20, 0 and 80.

A validation procedure was conducted for the method of quantifying lactic acid standard (Sigma-Aldrich ® , Europe) content by means of HPAEC with conductivity detection by determining two ranges of linearity: from 0.001 to 0.1 mg ml -1 , where the equation was f(c) = 25,196 c; and from 0.1 to 0.6 mg ml -1 , where the equation was f(c) = 19,021 c + 0,684. The lower limit of detection was established at LOD = 60 mg ml -1 and the limit of quantification at LOQ = 180 mg ml - 1 . The precision of the method was expressed as standard deviation of repeatability S r at 0.0045 mg ml -1 and the repeatability limit r at 0.012 mg ml -1 .

Discussion

Sample chromatograms of apple juice at various temperatures during fermentation conducted with the use of the strains of Lactobacillus brevis and Lactobacillus plantarum at various stages of the fermentation process are presented in Figure 1 and Figure 2.

Results for lactic acid content obtained with the use of HPAEC, enzymatic tests and biosensors on particular days of fermentation at both temperatures are shown in Figure 3a and3b for Lactobacillus brevis at 20 and 30 0 C, respectively, and Figure 4a and4b for Lactobacillus plantarum at 20 and 30 0 C. All the analyzed samples of apple juice contained lactic acid. The concentration of L-lactic acid anions increased during fermentation conducted at both 20 and 30 0 C but significantly higher content of lactic acid was noted at 30 0 C. A greater increase in lactic acid was observed in the case of fermentation conducted with the use of Lactobacillus brevis strains. At 20 0 C, an increase in acid concentration was observed from 0.10 g l -1 at 0 h to 0.22 g l -1 at 96 h of fermentation, while at 30 0 C from 0.13 to 0.30 g l -1 at 0h and 96h, respectively. At the same time, results obtained by means of enzymatic tests were at a similar level: from 0.12 to 0.19 g l -1 (at 0 and 96 h of fermentation) at 20 0 C and from 0.10 to 0.25 g l -1 at 30 0 C, respectively. Biosensors were used only to determine the level of the L-lactic acid isomer. In the case of the ABT biosensor, the concentration of L-lactates in samples inoculated with Lactobacillus brevis was 0.05 g l -1 at 0 h to 0.16 g l -1 at 96 h (at 20 0 C) and was similar to that of L-lactates quantified by means of enzymatic tests, which were 0.06 -0.13 g l - 1 , respectively. The EKF biosensor, as compared to enzymatic tests, produced lower values for Llactic acid, which were from 0.03 g l -1 at 0 h to 0.1 g l -1 at 96 h of fermentation at 20 0 C, while at 30 0 C these were from 0.02 to 0.16 g l -1 , respectively. In the case of fermentation by Lactobacillus brevis it was not possible to determine lactic acid content at 168 h, as the samples became moldy.

Lactobacillus plantarum strains caused a much lower increase in the acid at either temperature. In the case of juices inoculated with Lactobacillus plantarum at 20 0 C, no significant increase in lactic acid concentration was observed. Acid content produced by Lactobacillus plantarum measured by means of the HPAEC technique and the ABT biosensor was similar and corresponded to L-lactic acid content determined by means of enzymatic tests. There wos no significant increase of lactic acid content during fermentation at 20 0 C. At 30 0 C the concentration of lactic acid measured by HPAEC increased from 0.11 to 0.18 g l -1 . In the case of the EKF biosensor, at both temperatures acid concentration was below the quantification limit of the apparatus.

Enzymatic tests made it possible to determine particular isomers of lactic acid: D-and Llactates but during the process of fermentation, only the concentration of the L-isomer changed.

Enzymatic tests are a popular method for determining the content of various components that is used in the industry; however, they are a time consuming technique as it is necessary to perform a separate analysis for every component to be quantified. The use of biosensors also involves some inconvenience, and during analyses it was observed that PVPP sample discoloring at low concentrations led to overestimated results in the case of ABT. During EKF analyses, subsequent repetitions of determinations resulted in increasing figures [START_REF] Przybyt | Zastosowanie biosensorów do oznaczania mleczanów w owocowych sokach komercyjnych i koncentratach, śywność[END_REF]. The HPAEC technique with conductivity detection used in the research produces results that are comparable with popularly used reliable enzymatic tests. It is a simple technique which does not take much time or a large number of tests for analysis. HPAEC seems to be an extremely useful method for exact determination of lactic acid content in fruit juices. However, due to the high cost of an ion chromatograph, it is hard to unequivocally decide the viability of this method for on-line control of the technological process. However, it seems to be a very good, exact, and sensitive method for periodical control of organic acid concentration in fruit juices.

Conclusions

On the basis of the results obtained, it was found that:

1. During fermentation caused by lactic bacteria (at both 20 and 30°C), L-lactic acid content increases, while the concentration of D-lactates remains at the same level. However, in the case fermentation by Lactobacillus brevis the increase of lactic acid was significantly higher than in the case of Lactobacillus plantarum.

2. High performance anion exchange chromatography with conductivity detection makes it possible to precisely determine lactic acid in juices as it gives results comparable to the popularly used reliable enzymatic tests, and thus it allows for on-line monitoring of contamination of fruit juices with lactic acid. Additionally, the simplicity of the method, the small volume of samples and short time of analysis to obtain information about the ion composition of the material studied, makes the HPAEC technique particularly suitable for periodic control of organic acid concentration in fruit juices.

3. The final choice of the device (HPAEC, enzymatic tests or biosensor) by the future user (juice producing company) should be determined by its particular demands (simplicity of the measurements, possibility of usage at line) and economical impact (price of the device and consumables).

  ). Chromatographic analysis was recorded with the use of the programme Chromeleon ® , version 6.70.

Figure 1 .

 1 Figure Captions:

Figure 2 .

 2 Figure 2. Sample chromatograms of apple juice inoculated with Lactobacillus plantarum after 0h, 48h and 96h.

Figure 3a .

 3a Figure 3a. Lactic acid content determined by means of ion chromatography, enzymatic assays and biosensors (ABT and EKF) during fermentation conducted with Lactobacillus brevis strains at 20°C.

Figure 3b .

 3b Figure 3b. Lactic acid content determined by means of ion chromatography, enzymatic assays and biosensors (ABT and EKF) during fermentation conducted with Lactobacillus brevis strains at 30°C.

Figure 4a .

 4a Figure 4a. Lactic acid content determined by means of ion chromatography, enzymatic tests and biosensors (ABT and EKF) during fermentation conducted with Lactobacillus plantarum strains at 20°C.

Figure 4b .Figure 1 .Figure 2 .Figure 3b .Figure 4a .

 4b123b4a Figure 4b. Lactic acid content determined by means of ion chromatography, enzymatic tests and biosensors (ABT and EKF) during fermentation conducted with Lactobacillus plantarum strains at 30°C.

http://mc.manuscriptcentral.com/tfac Email: fac@tandf.co.ukFood Additives and Contaminants

Acknowledgements. This work was supported partially from the EU-FP6 project Quali -Juice /COLL-CT-2005-012461/ and Ministry of Science and Higher Education in Poland.


Keywords: inquiry-based teaching, laboratory work, language, teacher knowledge, science education

With a focus on the use of language related to scientific inquiry, this paper explores how 12 6 secondary school science teachers describe instances of students' practical work in their 7 science classes. The purpose of the study was to shed light on the culture and traditions of 8 secondary school science teaching related to inquiry as expressed in the use of language. Data 9 consisted of semi-structured interviews about actual inquiry units used by the teachers. These 10 were used to situate the discussion of their teaching in a real context. The theoretical 11 background is socio-cultural and pragmatist views on the role of language in science learning. 12

The analysis focuses on two concepts of scientific inquiry: hypothesis and experiment. It is 13

shown that the teachers tend to use these terms with a pedagogical function thus conflating 14 methods of teaching with methods of inquiry as part of an emphasis on teaching the children 15 the correct explanation. The teachers did not prioritise an understanding of scientific inquiry 16 as a knowledge goal. It is discusses how learners possibilities to learn about the characteristics 17 of scientific inquiry and the nature of science are affected by an unreflective use of everyday 18 discourse.

Introduction 26

The call for scientific literacy as a general goal for science education has emphasised the need 27 for students to develop an understanding beyond scientific concepts and skills. An 28 understanding of scientific inquiry and the nature of science (NOS) is regarded as 29 fundamental to scientific literacy [START_REF] Roberts | Scientific Literacy/Science Literacy[END_REF]. Today, many policy documents, curricula 30 materials and programmes world wide are based on the idea that inquiry should be a guiding 31 principle in science education (National Research Council (U.S.), 1996;[START_REF] Rocard | Science education now : a renewed pedagogy for the future of europe. 858 Luxembourg[END_REF]. 32

Despite the diversity and situatedness of research on inquiry based science education (IBSE) 33 internationally, Abd-El- [START_REF] Abd-El-Khalick | Improving science teachers' conceptions of 766 nature of science: a critical review of the literature[END_REF] found that many themes and issues cut across 34 national boundaries -supporting the relevance of the present study. 35

The idea that inquiry should be a guiding principle in science education is not new. 36

Neither is the idea that students need to develop an understanding of what scientific inquiry is 37 and some insight into NOS [START_REF] Deboer | A history of ideas in science education : implications for practice[END_REF]. At the beginning of the last century Dewey wrote 38 extensively about the idea of inquiry as an organising principle in education and particularly 39 in science education [START_REF] Dewey | How we think : A restatement of the relation of reflective thinking to the 795 educative process[END_REF](Dewey, , , 1916(Dewey, /2004). However, the promotion of inquiry in 40 science education has been accompanied by widespread confusion about its meaning. Almost 41 twenty years ago DeBoer (1991) concluded that teachers continue to be unclear about the 42 meaning of inquiry and confuse the idea of inquiry as a teaching strategy with inquiry as a 43 learning outcome. In Sweden, arguments about practical work in science education in terms 44 of a content to be learned or as pedagogical strategy were mixed considerably already at the 45 time of Dewey [START_REF] Kaiserfeld | Laboratoriets didaktik: Fysiken på läroverken i början av 1900-talet[END_REF]. In order to facilitate discussions about NOS and scientific inquiry for educational 75 purposes, [START_REF] Lederman | Syntax of nature of science within inquiry and science instruction[END_REF] suggests the following distinction: 'it is useful to conceptualize 76 scientific inquiry as the process by which scientific knowledge is developed and, by virtue of 77 the conventions and assumptions of this process, the knowledge produced necessarily has 78 certain unavoidable characteristics (i.e. NOS) ' (p. 308). This shows the close connection 79 between scientific inquiry and NOS; however, there is still a serious ambiguity as to how 80 scientific inquiry is presented in educational reforms and curricular documents. Generally 81 speaking, scientific inquiry can refer to three different ideas in education: 1) a set of skills to 82 be learned by students; 2) a cognitive understanding of the processes of inquiry, e.g. the logic 83 of a controlled experiment; and 3) a pedagogical strategy [START_REF] Bybee | Teaching science as inquiry[END_REF]. Lederman (2004) 84 argues that the third idea of scientific inquiry is most strongly communicated to teachers in 85 reform documents. 86

Previous research 87

The increased interest in socio-cultural perspectives on teaching and learning has been 88

accompanied by a focus on the role of language in science teaching and learning. For example 89 in his seminal work Talking Science [START_REF] Lemke | Talking science : language, learning, and values[END_REF] suggests that 'learning science is learning 90 to talk science'. [START_REF] Yore | Examining the literacy component of 890 science literacy: 25 years of language arts and science research[END_REF], in their review of research on language in 91 science education, make clear that any kind of inquiry or hands-on activity must be 92 complemented by an active engagement with language at all levels: speaking, listening, 93 writing and reading. Just 'doing','exploring' and 'experimenting' are insufficient. Scientific 94 inquiry, both in an educational and research sense, is conducted through highly developed 95 uses of language [START_REF] Wellington | Language and literacy in science education[END_REF]. [START_REF] Carlsen | Language and science learning[END_REF] has suggested that an 96 important area for further research is language as an educational outcome rather than just as a 97 means. Furthermore, language-oriented activities must be accompanied by explicit 98 instructions in terms of purpose, audience, style and role in science and knowledge building. 99 [START_REF] Crawford | Creating authentic opportunities for presenting 788 science: The influence of audience on student talk[END_REF][START_REF] Yore | Examining the literacy component of 890 science literacy: 25 years of language arts and science research[END_REF]. [START_REF] Yore | Examining the literacy component of 890 science literacy: 25 years of language arts and science research[END_REF] note that the quality 100 and quantity of oral interaction in science classrooms is generally low and unfocused. 101

Learners do not necessarily develop an understanding of inquiry as a result of 102 participating in inquiry activities [START_REF] Trumbull | Developing materials to promote 865 inquiry: Lessons learned[END_REF]. Similarly, 103 learners do not generally develop an understanding of NOS as a result of engaging in 104 scientific inquiry alone, regardless of whether the learners are school students, teachers or 105 scientists [START_REF] Schwartz | Developing views of nature of 862 science in an authentic context: An explicit approach to bridging the gap between 863 nature of science and scientific inquiry[END_REF]. For learners to develop an understanding 106 of inquiry and NOS they also need, besides from the proper experiences, guided attention to 107 and explicit reflection on these topics (Abd-El-Khalick & [START_REF] Abd-El-Khalick | Improving science teachers' conceptions of 766 nature of science: a critical review of the literature[END_REF]. A prerequisite for 108 this is that teachers have an understanding of inquiry and NOS and such an understanding is 109 intrinsically connected to teachers having a functional language in order to be able to help 110 learners to reflect on these topics. [START_REF] Bartholomew | Teaching Students "Ideas-About-769 Science": Five Dimensions of Effective Practice[END_REF] studied what 111 factors that become important when teaching 'ideas-about-science' and concluded that they 112 came to see teachers' use of discourse as particularly significant. In contrast to discursive 113 patterns that only focus on factual knowledge, patterns that invite learners to formulate 114 arguments and relate these to theory and evidence are important in modelling authentic 115 epistemic reasoning. This result was corroborated by [START_REF] Kelly | Co-Constructing Inquiry-Based Science with Teachers: 815 Essential Research for Lasting Reform[END_REF] in his review on research 116 on discourse practices in science classrooms. Because teachers direct how learners meet new 117 discourses through interaction with different forms of language from different sources and in 118 different contexts, studying their use of language is highly relevant [START_REF] Leach | Individual and Sociocultural Views of Learning in Science 825 Education[END_REF]. 119

Researchers have focused on teacher education and teachers' professional development to 120 improve meta-knowledge of inquiry and NOS. Pre-service science teachers often have most 121 of their experience with science from college courses. Unfortunately college courses in the 122 natural sciences rarely go into any depth in teaching about scientific inquiry and NOS. Pre-123 service teachers need first-hand experience of inquiry as well as practice in translating these 124 experiences into inquiry-oriented lessons in their own future teaching (Britner & Finson, 125 2005). [START_REF] Windschitl | Folk Theories of "Inquiry:" How Preservice Teachers Reproduce the 878 Discourse and Practices of an Atheoretical Scientific Method[END_REF] has described how pre-service teachers with an undergraduate 126 degree in science often are well steeped in a school tradition which equates scientific inquiry 127 with "the scientific method". However, the scientific method, as an algorithm of a few steps 128 performed in a linear fashion has been recognized as seriously misrepresenting science 129 [START_REF] Rudolph | Portraying Epistemology: School Science in Historical Context[END_REF]. Also, [START_REF] Windschitl | Transcending Simple Forms of School Science 881 Investigation: The Impact of Preservice Instruction on Teachers' Understandings of 882 Model-Based Inquiry[END_REF] found that pre-service teachers, 130 even with experience of authentic scientific inquiry, are not used to reflect on the role of 131 theories, models and hypotheses in scientific inquiry. To create successful courses it is 132 important to know about teacher students' and teachers' conceptualizations of inquiry 133 (Windschitl, Thompson, & Braaten, 2008b). 134

Teachers' conceptualizations of inquiry are more complex that those of teacher students 135 because they often take into account wider dimensions of the school context. Nevertheless, 136 teachers are often better at articulating what inquiry is not, rather than what it is, e.g. it is not 137 following a step-by-step procedure, just reading the textbook or getting answers directly from 138 the teacher [START_REF] Lotter | Overcoming a Learning Bottleneck: 836 Inquiry Professional Development for Secondary Science Teachers[END_REF]. Moreover, teachers' use of inquiry-based 139 practices were found to be guided by four core conceptions, viz. those of science, their 140 students, effective teaching practices and the purpose of education (Lotter, Harwood, & 141 Bonner, 2007). [START_REF] Kang | Secondary science teachers' use of laboratory 810 activities: Linking epistemological beliefs, goals, and practices[END_REF] found that teachers' naïve epistemological beliefs, 142 but not necessarily their more sophisticated beliefs, were reflected in their use of laboratory 143 activities. They suggested that this was because teachers had to negotiate their 144 epistemological beliefs as part of the teaching context and their educational goals. Evidently,145 there are tight interconnections between teachers' inquiry teaching practices and educational 146 goals. 147 [START_REF] Luft | Changing inquiry practices and beliefs: the impact of an inquiry-based 842 professional development programme on beginning and experienced secondary 843 science teachers[END_REF] changed their beliefs more than their practices whereas more experienced teachers changed 150 their practices more that their beliefs. In a similar study teacher students were found to 151 acquire a deeper understanding of inquiry as a result of a pre-service course on inquiry if they 152 already had a more developed conceptualization of inquiry, whereas those who did not 153 benefited less from the course [START_REF] Windschitl | Inquiry projects in science teacher education: What can investigative 875 experiences reveal about teacher thinking and eventual classroom practice[END_REF]. 154 Keys and Bryan (2001) draw attention to the lack of research on inquiry practices 155 designed by teachers as opposed to by educational researchers. They recognize the need to 156 develop a mutual language of overlapping cultures to frame, not only student-teacher 157 interaction, but equally importantly researcher-teacher interactions. 'Only when the voices of 158 researchers are in resonance with the voices of teachers can we begin to create harmonized 159 reform-based instruction that is enduring' (p. 642). A similar conclusion was reached by 160 [START_REF] Fredrichsen | Brokering at the Boundary: A 800 Prospective Science Teacher Engages Students in Inquiry[END_REF]. They concluded that it is critical to support ways for 161 teachers and teacher educators to participate in each other's communities of practice. Most 162 studies on inquiry-based teaching have involved programmes designed by researchers and 163 taught by expert teachers; therefore more studies of how teachers ordinarily use and 164 conceptualize inquiry on their own initiative are needed. Also, since most studies involve 165 elementary and middle-school teachers and students, more studies on inquiry practices in 166 secondary schools are needed (Keys & Bryan, 2001). 167

Method 168

Theoretical perspective 169

With this paper we want to contribute to more efficient communication between three 170 cultures: those of teacher educators, teachers and students. To do this we emphasise that 171 learning is not always unidirectional, i.e. students learning from teachers. Teachers may take 172 the role as students in communications with teacher educators during in-service training and teacher educators may learn from teachers and students about their current realities in the 174 classrooms. In this study however, we focus on teachers and note that it is their culture and 175 traditions that binds these three domains together. Teachers are also students and have many 176 years of socialization in school science behind them. 177

In this paper we take a pragmatist and socio-cultural perspective on language and 178 learning. From a pragmatist perspective on language, the meaning of a word is its use and 179 function in a specific activity [START_REF] Wickman | Learning as discourse change: A sociocultural 873 mechanism[END_REF]. A socio-cultural perspective on 180 learning means seeing learning as appropriation of discourse in a situated socio-historical 181 context [START_REF] Wertsch | Mind as action[END_REF]. Although science is characterised by a rich synthesis of linguistic, 182 mathematical and visual representations [START_REF] Lemke | Articulating Communities: Sociocultural Perspectives on Science 834 Education[END_REF], conceptual learning is orchestrated 183 through a discourse that require spoken and written language. Learning to see what is relevant 184 in an investigation is reciprocally connected to and often inseparable from learning to talk 185 about it or learning the relevant language game [START_REF] Bergqvist | Conceptually Blindfolded in the Optics Laboratory. 771 Dilemmas if Inductive Learning[END_REF]Wickman & 186 Östman, 2002a). A consequence of this is that what teachers are able to notice, and therefore 187 teach in science, depends on how they use language to make certain distinctions. A 188 prerequisite for teachers and students to gain access to words and concepts to talk about 189 scientific inquiry, and thereby participate in it and develop an understanding of the 190 characteristics of scientific inquiry, is that their teachers introduce and use a relevant language 191 that makes this possible. 192 This study is based on interview-conversations between a teacher and a 193 researcher/teacher educator about the teachers' use of inquiry oriented approaches. These 194 conversations revolved around the teachers describing their own teaching approaches and it is 195 within this activity that the words analysed in this paper have meaning. By centring the 196 interviews on concrete examples brought by the teachers from their own teaching units 197 (books, hand outs etc.), the conversations were situated close to their actual practice. As 198 conversations between a teacher and teacher educator the interviews also were situated within 199 the broader context of teacher education, i.e. the talk analysed in these interviews is the type 200 of discourse teacher educators and authors of curricular materials will have to relate to. 201

The teachers: selection of participants 202

As the study was both explorative and qualitative, diversity was considered as being more 203 important than a random selection of participants [START_REF] Neuman | Social research methods : quantitative and qualitative approaches 850[END_REF]. In order to achieve 204 diversity in terms of different kinds of experiences and backgrounds, we based the selection 205 on three criteria: years of experience as a teacher, equal number of men and women and 206 schools in a variety of neighbourhoods. Twelve teachers were interviewed with teaching 207 experience ranging between 5 and 30 years. The teachers' experience also varied with regard 208 to in-service training with regards to inquiry practices. 209

Interviews 210

In order to obtain data on teachers' ways of describing their teaching, with a focus on inquiry 211 oriented approaches, semi-structured interviews seemed to be the most natural starting point. 212

Another possibility would have been to ask a series of questions about how they use inquiry 213 in their teaching and how they work with particular aspects of language in such situations. 214 Such a battery of questions would suggest certain types of answers and exclude others, 215 however, and was considered too guided -especially considering that our initial aim was to 216 form an overall picture of different possible ways of talking about inquiry. Cobern and 217 Loving (2000) used a similar approach to the one adopted here in a study on teachers' enacted 218

worldviews. 219

In describing teachers' use of language in relation to scientific inquiry in their own 220 teaching, we thought it important to connect the interviews to an authentic example that the 221 teachers had used in class. We therefore asked the teachers to bring an example (e.g. 222 instruction for lab work) from their own teaching that they thought represented an instance of 223 scientific inquiry (ett undersökande arbetssätt in Swedish). We defined instances of scientific 224 inquiry quite loosely on purpose as 'instances in which the students themselves find out 225 answers about nature through some kind of methodical study, experiment, field observations 226 or similar'. Here the idea was not to place too strict a limit on what might count as inquiry. 227 Also, by asking the teachers to bring an authentic example from their own teaching we 228 wanted to situate the interviews in the teachers' actual classrooms to avoid the inclusion of 229 too much romancing in their accounts [START_REF] Kvale | Interviews : an introduction to qualitative research interviewing[END_REF]. 230

During the interviews the first author asked the teachers to describe their examples and 231 used a template with terms and categories that were considered important and relevant to 232 inquiry in school science (see next section: Terms to Talk about Scientific Inquiry). The 233 intention was to ask the teachers about these terms in connection with the examples they 234 supplied [START_REF] Kvale | Interviews : an introduction to qualitative research interviewing[END_REF]. Even though a specific set of questions was not used, the following 235 questions served as a tacit guide during the interviews. 236

1. What terms are important in the description of inquiry as a part of the teachers' 237 practice? 238 2. What meaning do the teachers give these terms? 239 3. What function do these terms have as a part of their teaching? 240

This heuristic method was intended to produce an understanding of the teachers' use of 241 language without losing track of the context of school science and their own way of 242 describing their teaching. After establishing the examples and the words used by the teachers 243 during the interviews, more explicit and probing questions were asked with regard to the 244 meaning and use of certain words. Care was taken, however, to stay within the limit of the 245 relevant context and example. 246 Terms to talk about inquiry 247

Our purpose was to talk to the teachers about aspects of inquiry in science education in a 248 rather general way and thereby get a sense of the language of inquiry used by secondary 249 school teachers. In preparing for the interviews we did not make any particular distinction 250 between differences of inquiry in terms of research methods, teaching methods or targeted 251 knowledge in science education. Rather, our starting point was scientific inquiry as described 252 in science education research and policy documents. Even though all authentic research in the 253 natural sciences does not slot into the following structure, most academic research can be 254 described in the following way in retrospect [START_REF] Chalmers | What is this thing called science?[END_REF][START_REF] Derry | What science is and how it works[END_REF][START_REF] Johansson | Introduktion till vetenskapsteorin [Introduction to theory of science[END_REF]: 255 1. There is a starting point to inquiry. This can usually be conceived of as a question to 256 be addressed or a problem to be solved. 257 2. There are certain preconditions or a background against which the question or problem 258 is posed. This can be previous research, theories or models which are either used or 259 tested. 260 3. There are some characteristic ways in which inquiry proceeds to find answers to the 261 question or solutions to the problem. These involve the use of certain methods, a 262 striving for objectivity, and certain patterns of constructing arguments based on 263 assumptions about cause and effect, empirical evidence, predictions and Occam's 264 razor, etc. 265 4. The inquiry amounts to some sort of result or suggested consequences. Of paramount 266 importance in the academic research tradition is the idea of public examination of 267 research in the form of peer review. This means that to be deemed worthy, scientific 268 inquiry must result in some form of logical presentation that is intelligible to others, 269 usually in the form of a research report. In relating back to point 2, one could say that 270 the starting point and end result of scientific research is the research report. 271

Data analysis 281

Data analysis commenced with transcription of the recorded interviews. After reading through 282 these transcriptions a number of times and coding terms and sections related to inquiry, three 283 particular terms were chosen for further analysis, namely, hypothesis, experiment and 284 laboratory work (laboration, in Swedish) -the relevant sections of the transcriptions being 285 categorised according to these particular terms. We then studied the meanings given to them 286 by the teachers as they described their examples of inquiry units. In many cases the first 287 author drew attention to the inquiry related terms during the interview conversations and 288 asked the teachers to elaborate on them using the tacit questions mentioned earlier. Although 289 the starting point for the conversations was the teaching units used by the teachers, the 290 particular details of these are not necessary in order to understand the transcripts analysed in 291 this paper, as will become evident later. 292

Results 293

Talking about inquiry using the terms described above in the conversations proved to be more 294 difficult than we had anticipated. The teachers were more focused on the pedagogical aspects 295 of inquiry and on learning goals in terms of exemplifying natural phenomena and motivating 296 explanatory models. That is to say, the focus was on students' learning and understanding the 297 products of science as opposed to the processes of scientific inquiry. 298The examples provided by the teachers were mainly examples of practical tasks that the 299 students worked with for one lesson or less. Educational goals expressed by the teachers 300 included exemplifying a scientific concept (e.g. density) or theory (e.g. heat expansion), 301 providing experiences of certain phenomena (e.g. earthworms), making theoretical tasks more 302 concrete and linking them to real life experiences (e.g. calculating one's pressure on the 303 floor), varying the teaching, fostering curiosity and having fun in science class. Our 304 impression was that the main emphasis in terms of knowledge goal for the students was what 305 [START_REF] Roberts | Developing the concept of curricular emphases in science education[END_REF] called 'the correct explanation', and explained as 'the body of ideas accepted 306 by the scientific community at any given time'. Exemplifying scientific inquiry seemed to be 307 somewhat unusual in that it was only mentioned by two of the teachers and elaborated on by 308 one. In the latter case the teacher gave an example of learning to control variables by working 309 with a 'secret box', the content of which the students discovered by performing a variety of 310 different tests. 311 Surprisingly few of the terms used by the teachers related specifically to scientific 312 inquiry as conceptualized by us as researchers. In fact, the teachers only spontaneously 313 mentioned two of the terms on the list when talking about their examples: hypothesis and 314 laboratory report. The first author tried to probe and connect the other terms on the list to the 315 teachers' examples, sometimes asking about their use and function explicitly. One concept 316 that we thought might be particularly important was the concept of a research question and 317 that scientific inquiries start from some kind of a question [START_REF] Eggen | Strategies and models for teachers : teaching content 798 and thinking skills[END_REF]National 318 Research Council (U.S.), 2000). This was explicitly addressed in all but two of the interviews, 319 often using the term 'research question'. A related question was whether this was something the teachers used when talking with their students about instances of inquiry or laboratory 321 work, or in structuring their teaching. None of the teachers said anything to suggest that this 322 was an important concept in their teaching, or that 'research question' was a term they used. 323

Interestingly, one teacher returned to the idea of a research question much later, after it had 324 been brought up in the interview. She then used it in the sense of the students formulating a 325 question about what they wanted to or expected to learn from a unit of self-directed study in 326 biology. Although this can be said to be related to inquiry in the general sense of the word, it 327 did not relate specifically to scientific inquiry or learning about it. 328

In this paper we focus on the analysis of three terms that illustrate a certain feature of 329 the role of language in inquiry in secondary school science instruction: hypothesis, 330 experiment and laboratory work. The function given to the term hypothesis by the teachers 331 was primarily pedagogical, i.e. inquiry as a pedagogical strategy [START_REF] Bybee | Teaching science as inquiry[END_REF], which we 332 argue contrasts with its function in scientific inquiry proper. The terms experiment and 333 laboratory work were used synonymously, which also may have consequences for the 334 teaching of scientific inquiry. These three terms have a particular function when talking about 335 or during scientific inquiry and are referred to here as belonging to the category methods of 336 inquiry, but in the interview context they were used by the teachers to talk about educational 337 activities, or methods of teaching. This is explained in more detail in the following sections, 338 starting with the function of the term 'hypothesis'. 339

Hypothesis 340

The term 'hypothesis' was the only term that all the participants except one said they used 341 when talking to their students. In six of the interviews this term was introduced by the 342 teachers themselves when describing how they worked, and in five cases the interviewer 343 that it was deemed irrelevant to ask about its usage. All the teachers seemed to use 346 'hypothesis' as meaning an educated guess about what might happen in a laboratory task or 347 exercise. The term was given an important role and the students were often asked to state their 348 hypothesis as a regular part of laboratory work. The function given to this term by the 349 teachers seemed to be synonymous with that of a 'prediction', although this was not a term 350 that any of the teachers volunteered. In six of the interviews, the teachers were explicitly 351 asked whether 'prediction' was a word they used, and the answer in each case was 'no'. This 352 is not very surprising given that their use of the word 'hypothesis' made 'prediction' 353 superfluous, as one of the teachers also noted. 354

In contrast to the meaning the teachers gave to 'hypothesis' in this study, this term 355 usually has a different meaning in science studies and science proper. Here a hypothesis refers 356 to a possible or preliminary explanation of an observation or phenomenon. In science it is 357 common to put a lot of effort into formulating hypotheses in such a way that they can be 358 tested through some type of investigation and thus either be refuted or gain credibility. Part of 359 the logic of hypothesis testing is that one can derive predictions based on them, which is 360 normally what is then compared with the evidence at hand, so the actual hypothesis is often 361 tested indirectly. In this way the formulating and testing of different hypotheses can be part of 362 cycles of scientific inquiry aimed at describing nature by constructing ever more satisfying 363 theories [START_REF] Chalmers | What is this thing called science?[END_REF]. 364

The following quotes show how the teachers described the meaning of the term 365 'hypothesis' as they wanted their students to use it -an educated guess as to what they 366 thought might happen when performing a laboratory task. Or an assumption. 372 --------------------------------------------------------------------------------------------------373 Peter:

It ... in Year 7, you know, I always do these … shall we say, 374 very trivial investigations. You boil water. So I have, they 375 get to set up a hypothesis: 'Yes, how hot does the water get?' 376 and 'How hot is it after boiling for five minutes?' and so on. 377 ---------------------------------------------------------------------------------------------------378 Interviewer:

How do you explain it [hypothesis]? 379

Lina:

What result do you think you will get? What do you think 380 will happen? 381

The teachers' use the hypothesis as a call for students to take a stand or commit themselves to 382 a guess as to what the laboratory task will result in. For instance, the result might be some 383 kind of measurement, as in the case of the temperature of boiling water (Peter), or the nature 384 or value of whatever is being studied. Alfred also adds "an assumption" to his description 385 which could be read as an assumption about a possible explanation. This is however the 386 closest statement any teacher made in this direction and based on the rest of the interview we 387 believe it is better understood as an assumption about an outcome, i.e. a prediction. Several of 388 the teachers pointed to the importance of students trying to connect to their initial hypotheses 389 when writing a laboratory report. Thus, the meaning given to 'hypothesis' continues to 390 structure the students' activities when the practical part of the laboratory work is over. 391

The hypothesis primarily has a pedagogical function in their practice as described by the 392 teachers. By that we mean that the teachers ask the students to formulate a hypothesis, 393 meaning an educated guess, before they perform a laboratory task, primarily to help the 394 students learn the particular subject matter involved in the task. The pedagogical motivation 395 -------------------------------------------------------------------------------------------------- Well, we have said it so many times now that we don't have to translate it anymore, hypothesis, they know how to set one up … You have an idea about how it's going to be, roughly so. ¶ situation that is meant to help the students to remember the science content that the laboratory 397 task is meant to illustrate (Ann-Catherine). Furthermore, it draws the students' attention to 398 their own preconceptions or how well they have understood or not understood the theoretical 399 content being exemplified (Johan). Hence, it can also be seen as a way of creating conditions 400 conducive to an aha-experience if the results are contrary to those expected. 401

-------------------------------------------------- ------------------------------------------------- ¶ Deleted: teachers
Lina:

And sometimes it can just be a way to sort of concentrate 402 better, to think things through 'I see, yes but this should 403 probably have been blue here' or, for them to sit down, yes 404 be forced to think a little before one gets going. Otherwise 405 they rush away to get everything and get going at once 406 without them, then they don't know what they are doing. 407 -------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------- No, it's just, before they get started, then you so to speak go over the laboratory task and emphasise it, 'don't forget the hypothesis'. Sometimes I can say that you can't even touch the material until I have seen that you have a hypothesis.

Deleted: Lina:

And sometimes it can just be a way to sort of concentrate better, to think things through 'I see, yes but this should probably have been blue here' or, for them to sit down, yes be forced to think a little before one gets going. Otherwise they rush away to get everything and get going at once without them, then they don't know what they are doing. ¶ - -------------------------------------------------------------------------------------------------- What is made evident in these remarks is that the students are encouraged to formulate a 425 hypothesis, as an educated guess, in order to become more aware of their own learning and 426 have their own preconceptions be either challenged or confirmed. The pedagogical function is 427 also partly to control the students' attention to the task at hand. One teacher (Christian) even 428 said that he accepted a student's guess about the purpose of a laboratory task (to demonstrate 429 the presence of reduced sugars based on the chemicals given to the students) as a hypothesis. 430

His reasoning was that this demonstrated that the student had 'made the correct associations'. 431

Experiment vs. laboratory work 432

Another term that emerged as important in the conversations with the teachers was 433 'experiment' and its use as synonymous with laboratory work. The teachers seemed to use the 434 term experiment in an everyday sense as synonymous with testing, trying or doing something 435

without knowing what will happen. Therefore it is not strange that learning about experiments 436 as a conceptual content was not present in the teachers' discourse. In fact, only two of the 437 teachers in this study mentioned very briefly goals in terms of learning about scientific 438 inquiry, thus suggesting that even though teachers occasionally might have such aims, they 439 are not given a high priority. These two teachers also made no difference between the terms 440 experiment and laboratory work. 441

We had not thought about distinguishing between the terms experiment and laboratory 442 work prior to the interviews and this was an insight that evolved during the study. Reflecting 443 on how the term experiment is more commonly used in science inspired us to make a 444 distinction between an experiment as a method of scientific inquiry and laboratory work as a 445 method of teaching science. Although experiment has an everyday meaning that is 446 synonymous with testing or trying, in science the term 'experiment' is often used as an 447 abbreviation for 'controlled experiment', which is a technical term with a more precise 448 meaning. Different types of controls are used in different experimental set ups, as illustrated 449 by further specifications in the relevant terminology e.g. double-blind experiments and quasi 450 experiments. However, one could say that in essence the logic of a controlled experiment in 451 scientific inquiry is to make some change in a system and observe the result while trying to 452 control all the other variables thought to influence the result. The method is primarily useful 453 when studying causation and functions. In this context a hypothesis is a possible explanation 454 of the mechanism involved in the causation and is tested, often indirectly by deriving 455 predictions from it, through a controlled experiment [START_REF] Bock | Getting it right : R&D methods for science and engineering[END_REF]. 456 Laboratory work on the other hand as a method of teaching science, is a teaching 457 strategy or pedagogical activity, and as such it can have many distinct goals (Hofstein & 458 Lunetta, 2003). One goal could be to learn about controlled experiments as a specific type of 459 method used in scientific inquiry to answer a certain type of question, usually about causal 460 mechanisms. However, laboratory work could just as well be used for other educational 461 purposes e.g. to illustrate phenomena or theoretical concepts and thus focus on a particular 462 science subject matter as a learning goal. 463

The quote below shows how one teacher do not distinguish between the concepts of 464 ------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------- Another aspect of the use of the term experiment was that it seemed to be unproblematic 518 and used in an everyday sense. In particular learning to do an experiment or an 519 We have done that quite a lot. When we have written lab 536 reports and such. 537

Interviewer:

Yes 538 Lina:

When we, a lot when we were in the chemistry classroom 539 and did some lab work and so. 540

Interviewer:

Do you make any distinction between a laboratory task and 541 an experiment? 542 Lina:

No, I don't think so. Not for them. No. 543

[Later in the same interview] 544

Deleted: --------------------------------------------------------------------------------------------------- Mhm, Do you make any difference between laboratory work [laborationer] and experiments like that? ¶ Catherine: Ehm, no I can't say that I make any difference. ¶ In Catherine's statement, experiment seems to be something unproblematic in that she does not reason about it in terms of something to be conceptually understood or as a targeted knowledge. At the same time the students are expected to understand and be familiar with what an experiment is since they use it in order to learn other things. As became evident in the rest of the conversation, Catherine was not clear about the meaning of a controlled experiment. ¶ In this excerpt Lina talks about the assignment as an experiment, although in the rest of our 566 conversation, and particularly when specifically asked about this, she made no distinction 567 between experiment and laboratory work or investigation. Her comment that practising how 568 to design and carry out an experiment was not necessary shows that she does not talk about 569 this as a conceptual or procedural knowledge goal indicating that scientific inquiry is 570 unproblematic. Allowing the students to 'experiment' mainly has a pedagogical function in 571 that the purpose is that the students are supposed to be kept active and think that science is 572 fun, and bring in an element of play. 573

F

As a further illustration, Catherine in the quote below, seems to talk about an experiment 574 as unproblematic and does not reason about it in terms of something to be conceptually 575 understood or as a targeted knowledge. 576 Interviewer:

Mm. And then you mentioned hypothesis. 577 Catherine:

Yes. 578

Interviewer:

Apart from that this is something different than just 'atom' 579 and 'beaker', those are more like specific, 'hypothesis' is 580 something that can occur in any natural science subject. 581

Catherine:

Yes. 582

Interviewer:

Other subjects too, it doesn't have to be natural science ... 583

Catherine:

Mm. 584

Interviewer:

Or also experiment, observation, have you also discussed 585 such things? 586

Catherine:

Ehm… No … Experiment, yes, maybe that I have explained 587 that word yes … 588

Interviewer:

Now you are thinking about Year 6? 589 Catherine:

Yes, exactly, now I'm thinking about Year 6. 590

Interviewer:

And what about Years 7, 8 and 9? 591 Catherine:

Then you take it for granted that they should know what this 592 word is, experiment, what it stands for. 593

Formatted: Indent: First line: 0 pt Deleted: Sonya and Martin were also somewhat puzzled when asked whether they made any distinction between 'experiments' and 'laboratory work'. Sonya's expression is quite revealing and again suggests that, in terms of targeted knowledge, scientific inquiry is not something she has reflected about. Ehm, no I can't say that I make any difference. 596

Catherin does not seem to think the concept of an experiment merits special attention, yet at 597 the same time the students are expected to understand and be familiar with what an 598 experiment is since they use it in order to learn other things. As became evident in the rest of 599 the conversation, Catherine was not clear about the meaning of a controlled experiment. 600

These excerpts from the interviews with Alfred, Sonya, Martin, Lina and Catherine 601

show that for them the terms laboratory work and experiment are synonymous and indicate 602 that they do not reason about scientific inquiry in terms of a conceptual targeted knowledge. 603

We do not claim that the teachers, when they use the terms experiment or laboratory work, 604 "actually have in mind" either a pedagogical strategy or a particular research method such as a 605 controlled experiment, although it is possible. The point is that there is nothing to suggest that 606 they differentiate between the notions of an experiment and laboratory work in terms of 607 methods of teaching or methods of inquiry when they talk about their teaching. This is a 608 distinction we have introduced to make sense of how and why the teachers mix these terms 609 and seem so perplexed when asked about them. From our theoretical perspective the meaning 610 of a word is in its use in a particular situation. Thus, in the situation of a teacher talking with a 611 teacher educator and researcher about inquiry the terms experiment and laboratory work have 612 the same function and meaning. Furthermore, if these conversations also reflect how these 613 teachers talk with their students, the students' possibilities to learn about the characteristics of 614 certain methods of inquiry are thus lost in an unreflective use of everyday discourse. 615 --------------------------------------------------------------------------------------------------

Summary of results 617

In the analysis we have tried to show how use of the terms hypothesis, experiment and 618 laboratory work mix two categories of methods, namely, methods of teaching and methods of 619 inquiry. In terms of knowledge goals associated with scientific inquiry, this means a 620 conflation of means and ends. In other words, while 'hypothesis' and 'experiment' are used in 621 a way that aims at achieving learning goals associated with science content as a product, e.g. 622 theories, facts and models, the possibilities of developing a language to both talk and learn 623 about scientific inquiry and NOS seem to be limited. 624

We began with the assumption that in order to develop scientific literacy it is necessary 625 to have a grasp of how theories, knowledge claims, definitions and explanatory models are 626 developed in science. Learning about scientific inquiry can, for example, mean learning 627 something about the rationale and logic of scientific research methods. It can mean to 628 understand that scientific inquiries begin with a question and that a hypothesis is a 629 preliminary answer to that question or explanation of the phenomenon of study, often of 630 causal nature, and that a controlled experiment is a special method or type of investigation. 631

The result presented here suggests that in their teaching the interviewed teachers do not 632 reason about understanding scientific inquiry as conceptual knowledge. Instead they appear to 633 focus almost exclusively on knowledge goals in terms of learning the products of science and 634 the use of this knowledge. In order to achieve this aim they use certain methods of teaching, 635 which they describe as laboratory work, laboratory tasks and investigations or experiments 636 without differentiation. The students are asked to formulate hypotheses (guess the answer) 637 with the purpose that they learn and remember the correct explanation. One way of clarifying 638 the use of these terms in relation to scientific inquiry as targeted knowledge in school is to 639 differentiate between the categories of methods of teaching and methods of inquiry. In 640 focusing on developing knowledge about the products of science, terms like experiment and 641 hypothesis are subsumed under this purpose and functionally fall into the category of methods 642 of teaching. If the learning of scientific concepts and theories was the only objective of the 643 education this would not be a problem. But in order to learn about scientific inquiry these 644 terms are needed conceptually as a part of the category of methods of inquiry to be able to 645 learn the relevant distinctions of this aim. This would be an example of language as an 646 educational outcome rather than just as a means [START_REF] Carlsen | Language and science learning[END_REF]. Further research is needed to 647 establish exactly what teachers' language use is in the classroom and what it means for 648 students' learning about inquiry and NOS. 649

Possible explanations 650

Language is dynamic and subject to constant change. Words and expressions often evolve in 651 use and meanings change over time. In some cases the same word may have different 652 meanings and connotations in different activities simultaneously, as the present study 653 exemplifies. This is nothing new, and asking why a particular word is used in a certain way 654 may not prove very fruitful, since this often depends on multiple factors and contingencies 655 and whether the question demands a causal or teleological explanation. However, it is 656 interesting to note that many science teachers are themselves the products of an 'archetypal 657 education which has largely ignored the epistemic base and nature of its own discipline' (p. 658 659) [START_REF] Bartholomew | Teaching Students "Ideas-About-769 Science": Five Dimensions of Effective Practice[END_REF]. Traditionally, higher education courses in natural science 659 devote very little time and resources to reflection about inquiry and the nature of science. 660

Why the teachers in this study use the terms hypothesis and experiment in an everyday type of 661 language game may therefore reflect the way they have been taught natural sciences at 662 university level. To study the correlation between teachers' educational background and 663 experience with inquiry would have to be another study. However, we can note that the terms 664 analyzed in this paper was used in a very similar way by teachers with highly diverse 665

Possible implications 669

An interesting question relates to how using the terms analyzed here in particular ways 670 restrains or affords reflection and understanding [START_REF] Wertsch | Mind as action[END_REF]. In this study this amounts 671 to asking how these terms relate to educational goals associated with inquiry. The conflation 672 between terms relating to methods of inquiry versus methods of teaching can have 673 problematic consequences. For example, the development of controlled experiments has been 674

part of the development of science since the beginning of the scientific revolution and has 675 been enormously significant [START_REF] Chalmers | What is this thing called science?[END_REF]. However, exactly what it is, what it is for or 676 how it can be done it is not immediately obvious to someone new to science. One of the 677 teachers said that he did not expect his students to arrive at Newton's theory of gravity simply 678 by playing around with apples. Nevertheless, the way that he and most of the other teachers 679 talked about scientific inquiry as a pedagogical activity, unproblematic in terms of conceptual 680 learning, suggest that the students are expected to invent the principles of a controlled 681 experiment themselves by being 'given freedom to explore stuff'. Even though one of the 682 teachers (Ann-Catherin) gave an example of teaching the control of variables, she didn't talk 683 about this as a controlled experiment, and seemed to have difficulty in finding words to 684 articulate it. 685 A prerequisite for learning in institutional practices such as school science is that 686 learners are given access to a relevant discourse. What learners are given an opportunity to 687 distinguish depends on how language is used in reflecting on inquiry. This is so whether the 688 learners are students, teachers or scientists. the way this study suggests, then an important dimension for learning about scientific inquiry 694 is not available to explicitly reflect upon as part of the discourse the students are being 695 introduced to. Some teachers clearly expressed that they considered it important that the 696 students learn the correct language of science and use words in their correct scientific sense. 697

This concern about teaching students the correct use of scientific terms contrasted sharply 698 with the teachers' unreflective and everyday use of language in relation to scientific inquiry. 699

In addition to making communication about scientific inquiry more difficult, conflating 700 the categories methods of teaching and methods of inquiry may also be an obstacle to an 701 understanding of NOS. Let's have a look at what this might mean for some of the 702 characteristics of NOS [START_REF] Lederman | Nature of Science: Past, Present and Future[END_REF] has defined as important for K-12 instruction. One 703 aspect of NOS that may be more difficult to understand is the distinction between an 704 observation and an inference. Based on how the teachers in this study used the term 705 hypothesis, the students are left with observing and "guessing what will happen". However, 706 making inferences from observations often entails reference to the causal propositions stated 707 in a proper hypothesis. 708

A second example of NOS is that scientific knowledge is theory-laden. This is 709 associated with understanding the creative dimension involved in formulating hypothesises as 710 possible explanations. The formulation of hypotheses and the associated design of 711 investigations to test their validity and reliability are based on theoretical assumptions and the 712 results of previous inquiries, which is the essence of theory-ladeness. As [START_REF] Lederman | Nature of Science: Past, Present and Future[END_REF] meaningful. The purpose of the investigation is to find out how useful the hypothesis is in 718 order to explain the phenomena and make predictions about them. Understanding the use and 719 function of hypotheses is also relevant to understand the role of models in scientific inquiry 720 (Windschitl, Thompson, & Braaten, 2008a). 721

A third example of NOS that could be difficult to understand without a functional 722 language of scientific inquiry is that scientific knowledge is based on some form of empirical 723 observations and to understand the nature of adequate evidence to support scientific claims 724 [START_REF] O'neill | Examining the 852 potential of practice-based scientific literacy 853[END_REF]. A controlled experiment is an example of a structured way of 725 empirically deciding whether a hypothesis, as a preliminary explanation of a phenomenon, is 726

fruitful. An experiment (as a method of inquiry) is in this sense completely different from 727 conducting a laboratory task (as a method of teaching) in the classroom in order to make a 728 given theoretical concept come alive. Organising inquiries around simple predictions without 729 attempting to construct possible explanations or models will not promote reflection about the 730 connection between claims and evidence. 731 A limitation of this study being based on interviews with teachers is that one must be 732 careful when speculating about consequences for the classroom. However, this need not be so 733 much of an issue when one considers the implications for teacher education and in particular 734 in-service training. Nevertheless this study would benefit from an accompanying study with 735 classroom observations to test the validity of these finding in this context and see what 736 consequences that can be observed. One reviewer asked if a certain intertwining of 737 pedagogical and "authentic science" interpretations of inquiry might actually be desirable in 738 the classroom given the difference between these activities and the knowledge and goals of 739 their participants. Our argument is that it is precisely because the activities of scientist and 740 students in the classroom are so different in terms of knowledge and goals that the distinction 741 between methods of teaching and methods of inquiry needs to be clarified. The same reviewer 742 also suggested that if scientists were interviewed chances are that they might not always 743 express clear distinctions in regards to the terms analysed in this paper. We agree; however, if 744 philosophers of science and historians of science were interviewed chances are high that they 745 would agree with our definitions. The key here is that inquiry in science education has been 746 associated with learning goals in terms of learning about inquiry and NOS, i.e meta 747 knowledge about the practice of science and thus the domain of scholars of science studies. 748

Practicing scientist are normally not concerned with studying the practice of science, but 749 rather the workings of nature. School science is not just about teaching students the results of 750 science but also the results of science studies, that is about inquiry and NOS. 751 Teachers, teacher educators and authors of reform documents and curricula materials 752 need to be aware of the ways in which traditions of school science discourse can deviate from 753 the discourses the education is meant to introduce. If this is forgotten it is easy to talk past one 754 another and imagine that communication is taking place simply because the same words are 755 being used. Furthermore, the results of this study suggests that in secondary school, where 756 there is a long tradition of laboratory work in science education, it would be helpful to clarify 757 the distinction between methods of teaching and methods of inquiry. This is particularly 758

  studied how teachers' beliefs and practices of inquiry changed as a result of 148 participating in a professional development programme and found that inexperienced teachers 149

  Based on these reflections on scientific inquiry we formulated five categories of terms that we 272 hoped to focus on or incorporate into the conversation in a natural way during the interviews 273 in relation to the examples provided by the teachers. The first four are inspired byLederman 274 (2004) and the fifth was added as a link to the scientific practice of peer review. 275 1. Question: guess or hypothesis 276 2. Method: observation, experiment, scientific, systematic, objective 277 3. Previous knowledge: theory, model 278 4. Logical reasoning: critical thinking, evidence, cause, prediction 279 5. Presentation: report, review, comparison with other results 280

  brought it up in relation to their examples. In the one case where it was not used, the example 344 contributed by the teacher was so far removed from anything resembling scientific inquiry 345 Page 14 of 37 URL: http://mc.manuscriptcentral.com/tsed Email: editor_ijse@hotmail.co.

  Deleted: Interviewer: Do you talk about this as a hypothesis? ¶ Ingrid:Yes, what we write is: 'What do you think will happen?' Hypothesiswhat do you think will happen? We use both, right. ¶ -

  the wrong [answer], it doesn't matter if it didn't 409 turn out the way you expected, because then you have given 410 it some thought. And then the brain works so that if you have 411 thought about it, regardless of whether what you thought 412 would happen did or didn't happen, it is easier to take in new 413 things if you have thought about it first. But if you are 414 completely empty it is harder to attach new things. 415

  what does hypothesis mean? That it is your educated 417 guess, which as a rule is almost always wrong, but it doesn't 418 matter because that's not what is graded. But, you know, 419 that's where they have their previous knowledge from. So 420 Deleted: Deleted: Alfred: Many want to get started, you know, because they like the handicraft of laboratory work. But to pause for a moment before and think is harder you know. So they know what it means and signify but are sloppy about it. ¶ Interviewer: Do you have any tricks then or…? ¶ Alfred:

  experiment and laboratory work and an investigation. 465 Interviewer: Do you talk about lab work then, or is it an experiment or an 466 investigation or what? 467 Alfred: Well, ... I, I hardly know what the difference is between 468 those three concepts [nervous laughter]. No, but I guess it is 469 Formatted: Font: Italic Formatted: Font: Italic Formatted: Indent: First line: 0 pt Deleted: , Deleted: or doing something without knowing what will happenDeleted: We thought it was important to make a distinction between an experiment Deleted: scientific inquiry and laboratory work as a method of Deleted: . This means that laboratory work

Formatted

  and not something the students needed to be taught or 520 practice. Lina contributed an example that clearly could be used to illustrate a controlled 521 experiment. Her students were expected to examine earthworms to find out what sort of 522 environment they liked. They were supposed to find this out by doing two experiments 523 in which the dependent variable was where the earthworms liked to be and the 524 independent variable was either the amount of light or the degree of moisture preferred. 525 However, during the interview she talked about this in quite a different way: 526 Lina:And then, there's one[assignment] where they are supposed 527 do an experiment and investigate whether the earthworm 528 prefers light or darkness: 'write down how you did it and 529 your result in your journal', and then the idea is that they 530 shall think through how, how to best do that then. How can 531 you start to organise it? They sit together in groups of three 532 so that they can discuss. Then I guess each one should write, 533 but they can work together. 534 Interviewer: Do you talk about what an experiment is then? 535 Lina:

  ¶ Interviewer: Mm. And then you mentioned hypothesis. ¶ Catherine: Yes. ¶ Interviewer: Apart from that this is something different than just 'atom' and 'beaker', those are more like specific, 'hypothesis' is something that can occur in any natural science subject. ¶ Catherine: Yes. ¶ Interviewer: Other subjects too, it doesn't have to be natural science ... ¶ Catherine: Mm. ¶ Interviewer: Or also experiment, observation, have you also discussed such things? ¶ Catherine: Ehm… No … Experiment, yes, maybe that I have explained that word yes … ¶ Interviewer: Now you are thinking about Year 6? ¶ Catherine: Yes, exactly, now I'm thinking about Year 6. ¶ Interviewer: And what about Years 7, 8 and 9? ¶ Catherine: Then you take it for granted that they should know what this word is, experiment, what it stands for. ¶ Interviewer:

Formatted

  Deleted: as different things? Or is it the same thing, or? Deleted: Sonya:Yes … that … I don't think I have talked with them about that at all actually. ¶ Interviewer: What would you say a laboratory task is? And an experiment? Is there any difference in school? ¶ Sonya:(pause) No … we have never thought about that. Except if … now we do an experiment or now we do a test, now we do some lab work. ¶ Interviewer: Mm ¶ -

  ¶ Interviewer: Would you say that there is any difference between a laboratory task and an experiment when you speak in your classroom? ¶ Martin: Eh, no not in my opinion. I don't know what you mean now? ¶ Interviewer: Well, what you call the things you do. ¶ Martin: Yes …. No, but I don't know. No I say laboratory tasks, but they often say experiment. ¶ Interviewer: OK ¶ Martin: But I usually don't say that. Ehm. I believe they think its quite fun to do lab work, … actually. ¶ Interviewer: Mm ¶ The Deleted: Ingrid, Deleted: , Lina, Sonya Deleted: Martin Deleted:We suggest that this is associated with a conflation of two categories of methods, namely, methods of teaching and methods of inquiry, as part of an emphasis on teaching the right explanation.Deleted: only two of the teachers mentioned very briefly goals in terms of learning about scientific inquiry, thus suggesting that even though they occasionally might have such aims, they are not given very high priority. If Deleted: the wayDeleted: conceptualize inquiry when talkingDeleted: What we seem to find here is a lack of distinction between the activities of teaching and the activities of research, which results in some of the goals of science education being missed out.

  While earlier studies have shown an emphasis on the correct 666 explanation in teacher education is important[START_REF] Lager-Nyqvist | Att göra det man kan : en longitudinell studie av hur sju 820 lärarstudenter utvecklar sin undervisning och formar sin lärarroll i naturvetenskap 821 [To do the best with what you know. A logitudinal study of how seven student teachers 822 develop their teaching and teacher role in science[END_REF], further studies are 667 needed to ascertain what this might mean in terms of language use. 668

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  713puts it, 'science involves the invention of explanations'. An exclusive focus on predictions at 714 the cost of understanding the role and function of hypotheses as an attempt to explain 715 creative element of science to some sort of fortune telling. A 716 hypothesis, if an investigation derives from one, is what makes the actual scientific inquiry 717

  important in relation to educational goals associated with inquiry to clarify what it can mean 759 to learn about scientific inquiry and what this means for some commonly used words like 760 hypothesis, experiment and laboratory work. 761

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  Alfred seemed surprised by these questions and so did Sonya, Martin and Ingrid which 483 further illustrates how these teachers do not distinguish between the terms experiment 484 and laboratory task and that this seems to be an unusual topic for them to reflect upon. 485

	470 495	Interviewer:	a laboratory task, an investigation, an experiment, I don't Mm
	471	-	really know what the difference is but…
	472	Interviewer:	It is,
	473	Alfred:	Maybe there exists such a definition but …
	474	Interviewer:	Well, I am not sure about that, rather, what I am interested in
	475		is if it is used in any specific way. So if any difference is
	476		made between such words, if it matters or not?
	477 478 479	Alfred: Interviewer: Alfred:	F o r No, not, not for me I don't think it does. Mm [OK] No, I guess I use all three concepts a bit sloppily. F o r
	480 481	Interviewer: Alfred:	P Mm [OK] I should think. Yes, I have never thought about it but yes I P
	482		do.	e e
				e r e r
				R R
	486	Interviewer:	e Do you talk about, eh, laboratory tasks and experiments with e
	487 488 489 490	Sonya: Interviewer:	v i e w the students as different things? Or is it the same thing, or? Yes … that … I don't think I have talked with them about that at all actually. v i e What would you say a laboratory task is? And an w
	491 492 493	Sonya:	O n l (pause) No … we have never thought about that. Except if experiment? Is there any difference in school? … now we do an experiment or now we do a test, now we do O n l
	494		some lab work.	y y

  Terms such as 'hypothesis' and 'experiment' used 689 to talk about and during examples of scientific inquiry are parts of such a discourse. Students 690 communicating and thinking with them in contexts in which they have consequences and 692 become meaningful. If the term hypothesis is treated during inquiry oriented approaches in 693

	F o r
	P
	e
	e r
	R
	e
	v i e
	w
	O n l
	y

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for this is that it helps the students to focus on what they are doing (Lina, below) and creates a

learn about scientific inquiry by gaining access to such words, using them in action, and

Windschitl, M., Thompson, J., & Braaten, M. (2008b). How Novice Science Teachers

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