The Association for Science Education

C4.2 Videoclips and Educational Research

Abstract

This article is based on a video-clip produced by the author at Manchester Metropolitan University (MMU) in 1995 and used subsequently on the PGCE Secondary course and as the basis for investigating the understandings of science postgraduates within the concept area of evaporation and boiling of liquids (pure liquids and solutions.) This was used extensively as a research instrument during the period 1997-2002 in the UK and abroad. The research findings resulted in a number of publications, references to which are given in the paper. It is interesting that this process led to significant changes in the conceptual understandings of the author and to some, still controversial, ideas about boiling of solutions (of gases in liquids.)

Standards: This article is particularly relevant to Standards Q12, Q14 and Q26 but could have wider application and feed into teachers continuing professional development. It also provides material that can be applied to small scale educational research.

Key words: Evaporation, Boiling, Bubbles, Science Educational Research, Teachers' learning.C4.2  Evaporation, boiling and bubbles

Contents

1. Who are these materials for and what phase (primary or secondary)?
2. Describe content and format of materials.
3. Name of Digital Video clip
4. What are the expected learning outcomes?
5. What prior knowledge do student teachers and/or trainees need?
6. How do the learning and teaching materials assist teacher educators/student teachers and/or trainees in meeting the Standards?
7. Tutors' notes

1. Who are these materials for and what phase (primary or secondary)?

These materials were devised for use with science graduates - although with little adaptation they could be used with A-level students. The video itself is comprehensible to most pupils at the secondary stage and even in KS2. It is however designed as an assessment stimulus rather than as a teaching tool and the questions and discussion would need to be adapted to the audience.

2. Describe content and format of materials

These consist of the video used in the research, the questionnaire and details if subsequent publications. There is still a debate to be had as to whether fizzing drinks are examples of boiling solutions. (I am convinced that they are.) In fact. this can - and often does - lead to a very high level of debate even among experienced chemists.

3. Name of Digital Video clip

'Experiments' - Evaporation, boiling and Bubbles. A video produced at Manchester Metropolitan University.

4. What are the expected learning outcomes?

This topic will, hopefully, lead to consideration of the nature of understanding of scientific concepts and the importance of language (and the meanings of that language) in the learning of science. The very basic concepts of evaporation and boiling demonstrate a wide range of concepts held (and rarely explored explicitly) by experienced science graduates. This is a salutory lesson to be kept in mind when dealing with the understandings of pupils at earlier stages.

The topic can also be a useful introduction to exploration of an aspect of basic research methods in science education.

5. What prior knowledge do student teachers and/or trainees need?

Before using the video as a research instrument the tutor/trainee will need to be confident in contending with the theoretical ideas behind evaporation and boiling at an appropriate level of sophistication. The questions (and answers) will need to be carefully reviewed to ensure that they make sense to both the researcher and the 'students'. At least an elementary familiarisation with the techniques of educational research is needed.

6. How do the learning and teaching materials assist teacher educators/student teachers and/or trainees in meeting the Standards?

This article is particularly relevant to Standards Q12, Q14 and Q26 but could have wider application and feed into teachers continuing professional development. It also provides material that can be applied to small scale educational research.

7.0 Tutor Notes

Introduction                                                                                                                     

The video-clip showing instances of evaporation, boiling and bubbling was initially devised to provide a focus for discussion during some early ‘experimentation' with video-conferencing between different sites at MMU. These discussions showed that there were large variations in the explanations and understandings of colleagues in science education. Subsequently the video was used as the basis for discussions on the Secondary PGCE programme. 

This video can be used in various ways:

  • as a stimulus for discussion with students relating to thier undesrtandings of and explanations for the material in the 'experiments'. (The questions used in the research - see download in the next section will be helpful here)
  • as a more formal investigation into students' understandings of evaporation, boiling and bubbles, followed by feed back and discussion with the tutor.
  • as a 'model' to explore the understandings of others concerning a range of different scientific concepts.
The Scenarios Used in the Video-clip:

1.Evaporation:  Equal volumes of hexane (light petroleum) and water are left exposed in open beakers under the same conditions for about three hours. Each beaker was initially about half full.
2. ‘Forced' Evaporation: Air is blown through about 10cm3 of hexane in a 50cm3 beaker that is standing on a piece of wet wood.  The beaker becomes frozen to the wood.
3. Boiling Water: Water is heated in a beaker until it boils.
4. Reducing the pressure over water at room temperature: Air is extracted from a flask of water with a rotary vacuum pump until the water ‘boils'.
5. Water in a syringe: A small amount of warm water - about 40C - is sealed in a plastic syringe and the plunger pulled upwards until bubbles are seen. (In the video sequence a small bubble of air had been inadvertently left in the syringe.)
6. Opening cans of cola: Two identical cans of cola are left undisturbed at room temperature. Both are opened carefully, but the second is shaken vigorously immediately before opening and the first is not.  The affect of shaking is clear since much of the content of the second can is ejected forcibly from the opening.

The first scenario seeks to probe understanding as to why hexane (which has larger and thus, slower moving molecules on average at any given temperature) evaporates more rapidly than water under the same conditions. All of the other scenarios involve bubbles in some form or other, together with evaporation and/or condensation and these serve to focus on the more specific notion of ‘boiling'.

The Questions (and answers)                                                                                       

Download C4.2_2.0a provides the questions used in the formal aspects of the research together with some notes of the answers ‘expected' by the author.
Download C4.2_2.0a Questions and answers used in the research

The Research, Results and Discussion

A full account of the research and a discussion of the results was published in School Science Review (Goodwin 2003) The following download is a copy of the manuscript submitted for this publication:

Download K3.1_2.3b Evaporation and boiling: trainee science teachers' understandings.

The research video and questions were also given to groups of trainee science teachers in Colombia and in Finland and an early paper on the results from this was published (Goodwin 2000)

Of particular interest (to me) was the significant personal learning that took place during the development of the research: At the end of the pilot stage it was noticed that the question 'Is it boiling?' had been asked for all of the scenarios except the final one in which cans of carbonated drinks were opened. To be systematic it was decided to include the question here also although the anticipated answer was 'No'. Subsequently the author convinced himself that the answer ssould be 'Yes'! This has led to a number of publications (Goodwin 2001; 2002) and to discussions on science teacher training courses in many places around the world.

References
Goodwin A (2000) (with Orlik Y) ‘An investigation of graduate scientists' understandings of evaporation and boiling.' Revista de Educación en Ciencias 1 (2) pp 118-123. 
Goodwin A (2001) ‘Fizzing Drinks, are they boiling?' Journal of Chemical Education 78 (3) pp. 385-387
Goodwin A (2002)  ‘Teachers' continuing learning of chemistry: Some implications for science teaching.' Chemistry Education: Research and Practice in Europe, 3 (3) pp 345-359. (Available on the web at:  http://www.uoi.gr/cerp/2002_October/06.html )
Goodwin A (2003)   ‘Evaporation and Boiling - trainee science teachers' understandings.' School Science Review, 84 (309) pp 131-141. ISSN 0036-6811
                                                                                                          
Published: 26 Nov 2008