Video and lesson investigations on the topic of movement. Key concepts include:
- As wax drips from one end, that end becomes lighter so the candle tips the other way. The motion speeds up as the candle gets shorter, rather like a pendulum which swings more quickly the shorter it is.
- The candle begins rocking because of an imbalance of mass from one side of the candle.
- The motion continues because each side of the candle alternately has a greater loss of mass making it, for a moment, lighter.