When I was at school (seems a painfully long time ago now ;-) one of our science teachers did a class debate on heat transfer. He had half of us argue for Lavoiser's caloric theory and the other argue for particle theory. It was brilliant - I want to do the lesson with my year 8s but it was so long ago now I can't remember exactly what resources he used. Is this a lesson that anyone else has ever heard of/used, or do you think it was just made up by that particular teacher? This is a discussion of heat transfer rather than combustion. So, the two ideas are:

When I was at school (seems a painfully long time ago now ;-) one of our science teachers did a class debate on heat transfer. He had half of us argue for Lavoiser's caloric theory and the other argue for particle theory. It was brilliant - I want to do the lesson with my year 8s but it was so long ago now I can't remember exactly what resources he used. Is this a lesson that anyone else has ever heard of/used, or do you think it was just made up by that particular teacher?

This is a discussion of heat transfer rather than combustion. So, the two ideas are: 1) heat is a substance, a fluid with mass that flows from hot objects to cold objects, and 2) heat is caused by the particles in a material vibrating at different speeds. Bottom line is caloric was meant to be a fluid but it was not considered to have have mass. The basic lesson format that I have so far is: Present pupils with a history of the theories about heat transfer (go right back to the greeks). Then focus on the two theories that you have identified. You could develop the idea of the importance of heat in terms of developing technology (steam engines etc). Put pupils into opposing groups each of which defends one theory. Give pupils a pack of 'evidence' that supports their theories (e.g gases expand when they are heated because caloric is added). Pupils present their theory. Groups take turns in presenting an experiment or observation that supports their theory. The opposing group then gets a few minutes to explain the idea using their own theory. This could go on for several rounds. Hopefully this ends in a stalemate.....but this isn't essential. You then present some simple experiments- some of which would differentiate between the two theories.....I think it is important to have some that can be explained by both theories (examples: gases can be compressed- would caloric theory allow this?; Ice expands when it is frozen; You could cool another solid and see if it decreases in size; friction produces heat- would caloric theory explain this? ). Before doing the experiments pupils must predict, using their theory, what will happen and explain it to the class. Perform the experiments. Discuss the outcome. You can then discuss how a theory is invalid if it does not explain all of the data. Thats what I have so far. Still working on the ideas and experiments.

Have you seen this site? It has some extracts from the original work: http://webserver.lemoyne.edu/faculty/giunta/lavoisier2.html Ths one mentions some brief points and names that you could menion: http://faculty.njcu.edu/wmontgomery/Science_Experience/SciExch06.doc I've found these historical debates often quite hard to do in the past - one side tends to sort of know they're 'wrong' before they start if not careful The only thing I can find that may be useful at some point is a book 'From Phlogiston to Oxygen' by the ASE (and they had a smaller version of something similar which is now out of print, but may be around) See this URL http://www.ase.org.uk/htm/book_store/detail.php?SIID=123

Yeah, they will know they're wrong, because we're doing this right at the end of the topic. Perhaps, in retrospect, it would have been better at the beginning, but I felt that I'd rather they knew the facts first so that no one went away with the wrong idea (I can just imagine the potential exam responses... ;-) However, this is a good group and they've been good with role play type things before. I think they will be able to 'pretend' they've 'forgotten' the now accepted argument and get into it. Well, so far I have a handout explaining the caloric theory and a handout explaining the kinetic theory, with a bit of the history behind them. The kids are going to get told they have to argue for one side or the other. I'm going to pitch them as Lavoisier vs. Count Rumford. Not EXACTLY historically accurate, but they did live at the same time and they did hold opposing views, so it's not a million miles away. I'm not going to give them experiments to actually do, because I don't want them getting distracted with equipment and fiddling about. I'm going to give each group one or two "thought experiments" to consider though, and ask them to use their theory to explain the experimental results (a useful lesson in 'bending' theories to fit data ;-) They'll have one lesson to prepare a short, 5 min, presentation for their theory. Hopefully giving each group different thought experiments will avoid monotony when they actually present. Next lesson they'll do their presentations, the caloric groups first and the kinetic groups second. No questions until they're all finished; as they watch/listen, I'm going to insist that everyone writes down at LEAST one question that they want to ask at the end of all the presentations (hopefully, this will keep them quiet as well as making for a good debate). Then I'll pick people and they can ask each other the questions. Hopefully, we'll get a good class debate going. We'll see where it goes from there.

Well I did my lessons. It was a excellent differentiator, if nothing else! You could REALLY see the kids who work and -think- in lessons. Some of them really got into it, and were arguing away non-stop: A: "So if you can't SEE your caloric fluid, how do you know it exists?" B: "Well how do YOU know your particles exist?" A: "Cos they do!" B: "How do you know?" A: "We, um, saw them with a microscope" (Me: "no microscopes that powerful in those days I'm afraid") "Look, they just do ok!" B: "Well our liquid 'just does' too!" Hahah, it was brilliant :-) The caloric side had put a LOT more thought into their argument than the kinetic side. Probably cos the kinetic side had thought that since they were 'right' they wouldn't have to try much.