Waves

Background

You can make a version of Pepper's Ghost in the laboratory using a sheet of glass, two candles and a beaker. Place one candle out of sight of the audience and light it. The other candle, which is in the beaker, is behind the pane of glass at the position of the image of the lit candle. It will appear to the audience that this second candle is alight and it will amuse them to see water poured over this apparently burning candle. Of course, they will realise that it is a trick, but will get the point that the image of the flame is in the same position as the candle in the water.