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Blue bottle vanishes

    Blue bottle

    Shake the bottle and it turns blue. Leave it and the blue colour disappears.

    Ingredients and equipment that you will need

    Washing soda
    Fructose (fruit sugar)
    Hot water
    Methylene blue

    Method and further information

    Put one teaspoonful of washing soda and two teaspoonfuls of fructose (fruit sugar) in a bottle with 200 mls of hot water. Add a drop of methylene blue (which you can get from pet shops or aquarium supplies). When it goes colourless, shake the bottle.

    This mixture reacts with oxygen in the air and goes blue. There is air inside the bottle which mixes with the liquid when you shake it.

    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.