UNIT 5: WATER
Activity
INVESTIGATING SUBSTANCES THAT
CHANGE THE COLOUR OF WATER
5
In Activity 3, you learnt that water has no colour, it is colourless.
Is it possible to colour water? Let us nd out.
The activity will be carried out in groups of 4 to 6.
What you need
• clean transparent glasses or plastic cups • clean plastic spoons
• tap water • kitchen salt
• white sugar
• food colour
Instructions
1. Half ll the plastic cups/glasses with tap water as in Activity 4.
2. Observe all substances placed on the table.
3. Add each substance in turn to water in a dierent cup/glass.
4. Stir the water using a separate spoon each time.
Note down your observation by ticking (√) the correct box inTable 2. One example is given.
Some substances can change the colour of water.
Substances like food colour dissolve in water. The water becomes coloured.
Kitchen salt and white sugar dissolve in water. The water remains colourless.
So we have observed that some substances can change the colour of water.
What I have learnt
Table 2
White sugar
Kitchen salt
Food colour
The substance
dissolves (√)
Water becomes
coloured (√)
Water remains
colourless (√)
Substance
11