Small candle (birthday candle placed in lemon wedge works)
Match or lighter
Clear drinking glass or mason jar
Pour the water onto the plate and place the candle in the center of the plate. Light the candle. Place the glass upside down over the lit candle.
As the flame goes out the water will be sucked into the glass. The flame heats the air inside the glass. The air expands as it gets hotter. When the candle goes out, the air cools and contracts, causing the air pressure in the glass to drop. The air pressure inside the glass is less than the air pressure outside the glass. The pressure of the outside air pushes the water into the glass.