Expansion and contraction Most substances expand when heated and contract when cooled. This continues even after they have changed their states. For example, water will contract until it starts to freeze and turn into ice. It then starts to expand and get larger. Ice will expand until the temperature reaches about -3 C, after which is will start to contract again with lowering temperatures.
Ice is one of the few materials that expands when cooled.
Unfortunately, this is the cause of much of the damage to road in the winter. Water seeps into a small crack in the road, and then when it freezes, the ice expands and makes the crack bigger. Cars drive over the crack and loosen the material, so the water and ice can work again to make a pothole in the road. Temperature stays constant When you try to boil water, the energy you apply to the water is spent rising its temperature. Once all the water is converted to steam, the temperature of the steam can start to rise again.