Constant colour change

Constant colour change

This is great fun – keep adding different ingredients to see the colours change.

Ingredients and equipment that you will need

Bottle
Milk of Magnesia
Red cabbage indicator
Vinegar

Method and further information

Put a teaspoonful of Milk of Magnesia in a glass of water. Add some red cabbage indicator (see Make an Indicator) It goes green showing that Milk of Magnesia is an alkali. Add a little vinegar to neutralise it and it goes back to purple. Keep stirring and watch as it turns from red to purple to green again.

Add a bit more vinegar and the same happens.

Be careful – you should ask an adult to help you with these experiments. Do your experiments in old yoghurt pots, jam jars or bottle tops. Don’t use cups or glasses in case someone thinks it’s a drink.