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TGV11
Decomposition or combustion
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LINKS |
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Notes
on the video of heating a wooden splint.
Students should be able to suggest that
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the wood darkens
because it decomposes as it gets hot |
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there is a flame because the
decomposition gives substances in the gas state that
mix with oxygen in the air and the
temperature is high enough for them to react |
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the glow is produced
by carbon reacting with oxygen. |
Although it is not prominent in the video, a small amount
of ash is left behind.
Language Alert
We have not used the word ‘burn’.
This is because in everyday language it does not have a precise
meaning.
For example,
If we leave a cake in the oven too long so we are left with
charcoal, we say ‘we have burnt the cake’. A scientist
would say this is an example of decomposition.
For a gas cooker flame, we say ‘the gas is burning’.
A scientist would say that this is an example of combustion.
These are two quite different reactions and in science one
word won’t really do for both!
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Science Enhancement Programme CD-ROM 2005 |
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user
guide |
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