4 How can we tell the differences between physical and chemical changes?
1. What are the differences between physical and chemical changes?
Physical changes do not produce new matter while chemical changes do. How can we tell if new matter is produced?
Let’s take a look at the food we often eat!
2. Observe the two eggs in the pictures. Has the colour of the boiled egg changed? Is the change of the egg during cooking a physical change or a chemical change? Activity Booklet 28
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cook in boiling water
raw egg
boiled egg
3. Is it possible for matter to go through both physical and chemical changes during the changing process? Observe the burning candle carefully and answer these questions.
(1) What happens at the bottom of the candle flame? (2) Is new matter produced when burning? Where can we observe it?
burning candle
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