Monday, 18 May 2009

Demonstrate the rock cycle with a candle

All you need is a candle, something to scrape the wax off the candle, a piece of paper and some matches! Erosion is demonstrated as the wax is scraped off the candle, transportation by the pieces falling down on to the paper and deposition by the build up of pieces on the paper. It's then easy to continue to demonstrate compaction, metamorphism, melting and 'crystallisation'. However, which processes are NOT demonstrated? (Weathering, cementation, rising, extrusion, uplift).
This is a brilliant way to revise the rock cycle. Have you tried it yet? Click here to download the activity.
Earthlearningidea website has over 60 free Earth-related activities for you to try.

7 comments:

Jurassic Mike said...

I like this Chris! I have been using certain models as visual aids and explore non-correspondence of some aspects of those models to what they represent - e.g. cross setion of an egg to represent "layers" of the Earth ( crust, mantle, core). The egg shell, for instance, fails to show the oceanic and continental crusts. The thin film of albumin(?) may represent the uppermost mantle so that the egg shell and the film may represent the lithosphere. The egg is an excellent model but exploring non-correspondence encourages critical thinking. This demonstration of rock cycle using the candle is an excellent addendum. While, i think this is an excellent model of certain geologic processes (rock cycle), there may be non-correspondences to explore for a critical thinking exercise.

Chris, Earthlearningidea team said...

You're quite right Mike, in that the best discussions about modelling processes involve thinking about how a model is similar to reality, and also how it differs. If teachers use this approach to 'Rock cycle in wax', they should get the very best out of the activity.

Jane said...

Jane here - I use the egg as a model of the Earth demo - sometimes I start with an egg that has not been hard-boiled - just for dramatic siliness. With very young students I also start with toys - hold up a small car and ask the students if it is a real car? No - it is a model of a car; a dinosaur - its this a real dinosaur? Not it is a model of a dinasaur....etc. Then Is this a real egg? The students answer yes it is and I say "No it is a model of the Earth....". Another bit of silliness that works.

Mary from New Mexico said...

I, like Jurassic Mike, have often used an egg as a model for the Earth when introducing the structure of the Earth and plate tectonics. His comments encouraged me to think about the importance of how the model works and how it does not work. I once read somewhere that many students think that volcanic lavas are partly vinegar, because of the ubitquitous use of vinegar and baking soda models for volcanoes. In a workshop for future teachers that I just concluded, I began with a structure activity in which students were asked to explicitly list what aspects of the model were valid and what aspects were not. The first exercise in model evaluation was guided, but by the end of the workshop students were doing it independently.

Mary from New Mexico said...

To follow up on my previous comment, the future teachers really liked the rock cycle with a candle. They did evaluate how the model worked and then thought about extensions to other parts of the cycle.

Earthlearningidea team said...

Referring to Mary's first comment:- we certainly have not come across the misconception about volcanoes
containing vinegar! This shows how careful teachers must be in using small scale modelling of some of the Earth's major features, but also provides excellent scope for extending pupils' thinking.

Sully Creek Candles said...

great use of candles for science!