To sign candle, hold up your dominant hand vertically with fingers pointing toward the sky. Point your index finger from your non-dominant hand to the base of the palm of your dominant hand. Then wiggle the fingers of your dominant hand. The sign looks a little like your fingers are the flickering flame of a candle, while the non-dominant index finger is the wick.
Candles are an object of fascination for most children. You can use candles to introduce the idea of fire. You are can also teach candle in the context of a cake.