Non-specialists teaching physics can have a hard time. Jonathan Osborne offers some help
Poor old physics, it really has an image problem with young people these days. Why, you may ask? Physics presents us with a set of ideas that have always seemed strange. Just take the idea that a big brick falls no faster than a small pebble. Common sense tells you that can't be right - but it is. Likewise, the idea that day and night are caused by a spinning Earth seems to contradict the observation that clearly it is the Sun that moves. Or what about the idea that the reason the book on the table doesn't move is because the table pushes up? In short, the ideas of physics are strange. They present a vision of the world that is unconfirmed by everyday experience.
Then, there is the problem that physics deals in abstractions. Like it or not, most of us find it easier to think with ideas that are based on things that have concrete referents, so we picture the atom as being like a billiard ball. As for the inside of the atom itself we ask pupils to imagine it being like a mini solar system, with a nucleus in the middle and electrons whizzing round in orbits a long way away. Never mind the fact that the contemporary picture of the atom is something very different - this is a powerful picture which, while essentially erroneous, is at least a tool for thinking.
The same problems happen elsewhere. Energy is mistakenly portrayed as a substance, or an electric current like a flow of water - neither of which is true. The basic problem is that mere words are insufficient and that a more accurate representation of such phenomena requires the difficult language of mathematics. For instance, you can't do physics without measuring distances. No problem with that, we can all use rulers. But then you introduce the idea of speed and then accelerationI The more abstract it gets, the less significant physics seems to the everyday concerns of young people. This is sad for a number of reasons. It shows a failure to recognise that any significant learning is demanding.
More importantly, physics offers a totally different vision of the world.
That microwave is no longer a machine for defrosting your dinner, but a source of electromagnetic waves that shake the water molecules, transferring energy that raises the food's temperature to the point where it is good enough to eat. That very solid table in front of you is made of millions of atoms, whihch consist mostly of empty space. And a mobile phone sits in a sea of electromagnetic waves just waiting for the particular sequence of waves that are meant for your phone.
From car to computer, radio to radar, people who know some physics see the world in another way. And it's not just because they have a different language - it really is different. When you can see that the calcium in your bones was once made in some dim and distant star or that every time you breathe you share something of the order of nine molecules of Julius Caesar's last breath, then the world really is different.
Communicating these images is part of the challenge of teaching physics.
The Institute of Physics recognises that many key stage 3 teachers who have never quite got the physics plot, need help. This year and next they will be completing a set of six CD-Roms to help with all the topics in the KS3 scheme of work. These will contain a detailed explanation of the story that physics has to convey, lots of explanations of the difficult bits, and many resources to help with teaching. Yes, physics may be hard but, believe me, at the end it is a hall full of awe and wonder. Our students deserve at least a glimpse.
Jonathan Osborne is professor of science education at King's College London
* For details of the Supporting Physics Teaching initiative visit www.iop.org. Topic areas on the CD-Roms include energy and energy resources; light and sound; forces and their effects