Remove a coin from water without getting wet
Place a coin on a plate and pour a little water. Light a candle and place it in the middle of the plate. Cover the candle with an inverted glass and watch the water sucked up in the glass!!
The oxygen in the glass is consumed in the fire. The carbon dioxide produced dissolves in the water and leaves the glass. The pressure inside the glass becomes less than the atmospheric pressure outside since the oxygen was about 21% of it’s volume and as a result the water rises inside the glass.