Chapter 1 What underpins your teaching: matters of science and science education
Never say no to an experiment.
E. Chargraff (in Gaither and Cavazox-Gaither, 2002)
INTRODUCTION
The purpose of this chapter is to bring to your attention some matters that affect your science teaching in broad ways. How you perceive science shapes what you do in your lessons. Conceptions stem from many years of doing and learning science, so you may not be altogether conscious of them but they will, nevertheless, determine the flavour of your lessons. At the same time, your pupils will have their own conceptions of science and these will shape how they respond to your lessons. If you are aware of such conceptions you can take them into account. By the end of the chapter you should:
- know some key features of the nature of science;
- be able to justify the place of science in the curriculum;
- be aware of how you and others may think of science;
- know how models of science teaching could help you.
THE NATURE OF SCIENCE
What is science? Although you may have studied science for several years, this is not a question that crops up often, if at all. We tend to build our picture of science over time and from our experiences of it. Often, parts of the picture are fuzzy or vague so, how well do you know science? Task 1.1 is a warm-up exercise.
Task 1.1 Do you agree or disagree with the following statements about science?
Write either A (agree) or D (disagree) in the box next to each statement.
1 Science is not science without mathematics. | |
2 Science is about precise measurement. | |
3 Experiments can show scientific explanations to be true. | |
4 Experiments test scientific explanations. | |
5 The approaches to testing ideas in the various sciences are the same. | |
6 Science does not involve opinions. | |
7 Science establishes the truth about the world. | |
8 Scientific explanations are tentative until proved by experiment. | |
9 If an experiment to test an explanation is negative, that explanation must be abandoned. | |
10 Testing explanations with planned experiments is what makes science different. | |
11 Science is not contaminated by so-called creativity. | |
12 Scientific laws are patterns found in nature. | |
13 Scientific laws never change. | |
14 Scientists invent explanations about the world. | |
15 Being a scientist and being an historian is just the same, we both do our best to get at the truth. | |
If you have the opportunity, compare your responses with those of a colleague then read on.
WHAT IS SCIENCE?
Science is both:
- a process—a way of thinking and working to make sense of the natural world; and
- a product—a body of knowledge produced by that process, such as explanations.
It is also an activity that involves and affects:
These three aspects are evident in what follows.
Scientists makes sense of what we see around us by constructing explanations of them. Given that these explanations have some face value (they are consistent with the information to hand), scientists attempt to test these explanations empirically. This often means using an explanation to make a prediction and testing the prediction in a fair way. If the prediction is shown to be wrong, the explanation is probably wrong. For example, many people once believed the Earth to be flat. They pointed to the way the surface of a long, straight canal remained in view far into the distance. Flat-earther John Hampden was so confident of this that he offered £500 to anyone who could prove him wrong. The temptation was too much for evolutionary biologist Alfred Wallace. He placed three markers at equal distances along the Old Bedford Level Canal. Each marker was exactly 13 feet 4 inches above the surface of the water. The flat-earthers predicted that the tops of all the markers would make a straight line. The experiment, however, showed, that this was not so. When the last marker was viewed from the first, the central one was above the line of sight. Was this the end of the flat-earth theory? People do not always give up pet theories easily and this one rumbled on for many years, but Wallace got his money.
When faced with a theory that has failed its test, do you immediately reject it? Scientists are human and are not always quick to reject what seems like a good idea. They tend to re-examine the experiment to see if there is something wrong with it. This is not a bad thing, up to a point, but when an overwhelming number of scientists conclude that the explanation is wrong, that usually clinches it, at least, for the majority. But what if the prediction is shown to be right? Does this mean the explanation is right? Others may replicate your test and make new predictions and test them. Eventually, a pile of positive results begins to convince others that there is something in your explanation. In the case of the round earth theory, ships disappearing below the horizon and pictures of the Earth from space make for weighty evidence (but even the latter has been discounted as a confidence trick by the last of the flat-earthers). But that is not the same as saying a theory is certainly true. At some later date, it is always open to someone with another idea to pit it against yours. In the meantime, scientists usually busy themselves exploring how your theory works, making new predictions from it, and seeing how it fits in with other ideas.
Carefully constructed fair tests are not always possible in some branches of science. An explanation of earthquakes, the expansion of the universe, or the cause of human brain tumours might be difficult to test, for different reasons. Sometimes, however, it is possible to use naturally occurring events as sources of evidence. Note also that scientists who work in different areas can have different approaches and favour different kinds of experiment. For example, the comparison of a control and an intervention is quite common in biology and in medicine but less common in physics. Even medicine has its own flavour in its liking for ‘double blind’ experiments. In other words, the process varies from branch to branch of science. And, in practice, scientific study and investigation is rarely as clean and tidy as this might suggest, although it tends to appear so in textbooks after the event (Hussain, 2005; Reiss, 2005). Nevertheless, underpinning all is a desire to confront ideas with sound empirical evidence. It is the seeking of empirical evidence that gives science its strength and marks it off from other ways of knowing and other areas of the curriculum. The well-founded knowledge it produces may, of course, have practical application in technology. It is through technology that the majority of people know science and they may see science and technology as one (Feynman, 1998).
Task 1.2 Why flies don’t drop off ceilings
What could this case study teach a Key Stage 3 class about the nature of science?
Why don’t flies drop off ceilings? How do flies hold on, even when they are upside down? People just assumed that flies’ feet had suckers on them, a bit like those rubber suckers used to stick hooks on doors. John Blackwall wasn’t convinced by this explanation. He knew that suckers won’t work if there is no a...
