A magic trick that can be performed to amaze an audience, though a little bit of assistance may be required.
What you need:
- four glasses or jars that are the same size
- two plastic or waxed cards larger than the rim of the glasses – you can use some cardboard and cover it with contact paper
- a tray
- hot water
- cold water
- 2x different coloured food dyes
What to do:
- Fill two glasses or jars with hot water and two with cold water. They should be filled right to the brim.
- Colour the cold water with food dye, eg. blue.
- Colour the hot water with a different colour food dye, eg. red.
- Place one cold water glass in the tray and one hot water glass in the tray.
- Put the cards over the top of the other glasses, sealing them.
- Carefully, trying not to spill too much water, tip the glasses upside down, using the card to keep the water inside. Place the hot water glass on top of the cold water glass in the tray, and place the cold water glass on top of the hot water glass in the tray. Make sure the edges of the glasses line up.
- First, choose the glass with the cold water on top – slowly remove the card, making sure that the glasses stay lined up. You may need someone to help you hold the glasses in place. The two water colours should mix together.
- Then, choose the glass with the hot water on top – slowly remove the card, making sure that the glasses stay lined up. The two colours should stay separated.
What happens:
When the hot water is on top, the colours stay separated due to density. The hot water is less dense than the cold water, meaning that it is slightly lighter. When the cold water is on top, it sinks to the bottom because it is heavier.