Hot water makes the top off a closed bottle (or something like that) "pop" faster than cold water. As water gets heated, the molecules started moving faster and collide with each other more. They are moving from a liquid state (water) to a gas state (water vapor). As they collide, the pressure increases in the bottle. Soon, the pressure in the bottle, due to the collision forces of the molecules, is too great for the bottle to handle and the bottle top will pop off faster. Water at, let's say, 300 degrees Fahrenheit will cause the bottle to pop faster, and further, and if the water was 150 degrees even though water will be past boiling temperature in both bottles. When you have cold water, the molecules are not moving as fast and do not build that excess pressure.