Three cool science experiments that you can do at your home with your kid
Experiment # 1: Glass water and board experiment to demonstrate the power of air pressure.
The upward air pressure on the board from bottom is greater than the weight of the water inside the glass. That is why the board is holding up the water.
Experiment # 2: Glass water and candle experiment to show effect of air pressure variation
As the candle flame heats the air inside the glass, it expands and escapes out of the glass. When the inside air cools down, it contracts thus creates a vacuumlow pressure zone inside the glass. Therefore the high air pressure outside the glass pushes the water in. The flame goes out as the oxygen get exhausted.
Experiment # 3 : Glass water and egg experiment to explain buoyancy.
Adding salt into the water increases the density of the water, therefore buoyancy also increases to the egg as buoyancy is proportional to the density of the water. When buoyancy is more than the weight of the egg, it started floating.