Changes in Materials - Y5 Science
a chemical change which is irreversible. We looked at the changes in a variety
of materials when heated.
Observing Burning paper
The heat changes the paper colour to brown and black. An irreversible change.
Recording our observations
More recording of observations
Now we put some wood on to see if the heat will change the state of this material.
After a while the wood burst into flame.
There was quite a bit of smoke and a smell when this material burned.
The plastic material melted first.
So the shape changed and there was a gas given off.
We tried string to see what changes occurred.
It also turned brown and the heat pushed the string upwards.
The cotton fabric also turned brown but it took longer than the paper.
We could still see the pattern of the fabric even when it turned to ash after being burned by the flame.
Our conclusions were:- When a chemical change happens you might:
|* see the
colour of the substance change
* see a gas being given off
* see the substances burning
* see heat being produced
* see a new substance being made.