We have all spent time watching the toy duck, pictured on the right, dip its head into a cold glass of water. The red liquid inside the glass is methylene chloride. This liquid expands quickly when mildly heated. Click to see a 120 kb video of how quickly this liquid expands.

Explain what happens to the molecules of the liquid as heat is applied.

Explain why the column of liquid rises quickly when the bulb is touched.