A cool party trick or how to get a coin without wetting your hands
Warning! Under adult supervision.
- tinted water;
Toss a coin on a plate, fill it with tinted water. Put a candle on the water, light it and hold a glass over the top to warm the air inside. 30 seconds later, lower the glass onto the plate. The water draws in and the coin can be easily removed without wetting your hands. It is important that there is enough water so the neck of the glass is submerged. However, there should not be too much water, as not all the water will be sucked up. Try with the different amounts of water before showing off to your friends. It is also important not to press the glass too tightly to the bottom of the plate.
When heating the air inside the glass, it expands and some of the air is forced out. Once almost all of the oxygen has burned out, the candle goes out and the air begins to cool. The pressure in the glass decreases, and the external atmospheric pressure begins to push the water up into the glass and away from the plate.
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