Change Detective
Watch a change. Decide what happened and find the evidence.
Investigation scene
Press Watch change to see what happens.
Concept sketch
A new substance is the strongest evidence of a chemical change.
Your detective report
1. What type of change is it?
2. Which clue best supports your decision?
Live temperature comparison
The thermometer readings change as the scene plays. Temperature alone does not always prove a chemical change.
The chemistry
Physical change: the substance stays the same. Melting and dissolving are examples.
Chemical change: one or more new substances form. Examples include burning, rusting and cooking.
Signs may include a new colour, gas, heat or light, but any single sign is not always conclusive.
A physical change may absorb heat without immediately increasing temperature. The temperature values here represent simplified observations for classroom comparison.