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Education and outreach

Education and outreach

Practical hints for classy demos

11 Jan 2000

The Resourceful Physics Teacher: 600 Ideas for Creative Teaching
Keith Gibbs
1999 Institute of Physics Publishing 240pp £18.99/$30.00pb

One of my initial goals when I enrolled on my teacher-training course at Warwick University in 1996 was to develop a portfolio of demonstrations that would entertain, interest and also educate a class of 30 watchful pupils. As the course progressed and the practical workshops started, the tutors shared their experiences with us “pen-poised” student teachers. I wanted to remember every detail of every demonstration and practical, to go to bed with my file on my head and take in its whole contents by osmosis. Who, though, has the time for interesting, jazzy, practical work when there is a syllabus to get through, particularly when planning, teaching and managing lessons on one’s own for the first time?

Now, two years later and teaching in a comprehensive school in Oxfordshire, I am still learning the art of experimental demonstrations – and I know that I will be doing so for many years to come. There are simply not enough hours in the day to pick the brains of other members of staff and to share good ideas – although we do try to! All opportunities for new and exciting approaches are therefore welcomed with open arms. Fortunately, my local authority is very supportive and runs workshops that are an ideal opportunity to learn from experienced teachers.

However, I have now found a new bible. Keith Gibbs’ book provides teachers – especially those who are at the start of their teaching careers – with interesting and enjoyable demonstrations, experiments and ideas that can help to highlight specific points and to set students thinking. The book covers a range of topics that are suitable for both 14-16 year olds taking GCSE exams and for post-16 pupils taking A-levels. Teachers from other disciplines will also be able to use the book because background theory for each demonstration is included.

Reading The Resourceful Physics Teacher was a revelation to me, and I believe it will help new teachers to make their lessons and demonstrations appeal to a wide variety of pupils, which is crucial in today’s demanding classroom. I have already been able to try some of the practical suggestions with some of my students and I have attempted some of the demonstrations during the odd spare moment in the prep room.

Students find heat flow difficult – particularly the concepts of conduction, convection and radiation. However, the “cardboard serpents”, which are simply paper spirals that can be hung from the ceiling over something warm, have been great at illustrating the fact that heat rises. I found the best results were achieved when the spirals were suspended over radiators, which do not visibly give off heat. As for those students taking GCSE science, who only require a very simple explanation of heat flow, I found that a lava lamp (which can be bought easily from high-street shops) brought the subject alive.

There was, however, one practical that I would feel a little apprehensive carrying out with more disruptive pupils. It suggests that pupils should place their hands very close to a bunsen-burner flame to experience air as an insulator and over the flame to experience convection. This demonstration could, in my opinion, prove dangerous, and it would need to be extremely carefully supervised. However, the need for caution is not mentioned anywhere. I also felt that many of the radiation experiments would prove too complicated for GCSE, and might be better suited to A-level students. Having said that, a group of GCSE girls found that the experiment using two thermometers, one of which is covered in soot, illustrated the scientific idea of radiation well. Both thermometers are placed in water, which is heated until it reaches boiling point. The thermometers are then removed and placed in clamps. The rate at which the temperatures dropped is compared, with the blackened thermometer obviously cooling more rapidly.

Nuclear physics is an appealing topic to students, but they can become less enthusiastic when they realize there are very few practicals they can carry out in the subject. However, some of my year-10 pupils (and some sixth-formers) thought that “the match” demonstration to simulate a chain reaction was very effective. This involves standing about 20 matches in a block of wood, in a straight line, with their heads upwards. By lighting the match at the end, the rest of the matches light up one by one. (It is important to try this out yourself first as the distance between the matches is crucial!)

There is even one experiment on nuclear physics that pupils can carry out themselves. It illustrates the concept of half-lives and radioactive decay – and, I have to say, it works brilliantly. The only equipment you need is a collection of, say, 100 small wooden blocks, each of which has one face coloured. The whole collection of blocks is then shaken like dice, and those blocks whose coloured faces are visible are removed. The rest of the blocks are counted and recorded. This process is repeated until there are no blocks left, and a graph of the number of remaining blocks versus the number of the shake can then be plotted. The resulting curve gives an excellent representation of radioactive decay.

All in all, I thoroughly enjoyed dipping into the 600 ideas and have stored away many gems. The book is a must for any new physics teacher, although some explanations might not be detailed enough for the non-specialist. The book is also geared a little more towards A-level students and the more able GCSE candidates, with the result that demonstrations for less able pupils are harder to find.

Nevertheless, in teaching you have to grab help and suggestions where you can, and the author has managed to build a wonderful collection of useful hints. And if you worry that you may have seen or heard of many of them before, just keep reading: there will be plenty more that you will not have come across.

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