Ice melting is a global phenomenon that has many important impacts. It increases sea level, which poses challenges for coastal communities and disrupts the natural habitats of animals that live there. It also contributes to ocean acidification, a change in the pH levels of water that can harm marine life. And, perhaps most significantly, it accelerates the climate warming that is occurring, resulting in a self-perpetuating cycle of melting ice and rising sea levels.
The ice melts because it absorbs heat energy, which increases the kinetic energy of the water molecules that form the orderly crystal structure of the ice. As these molecules vibrate and heat up they break the hydrogen bonds that hold them together, causing them to move past each other rather than sticking together. As more and more hydrogen bonds break the ice begins to melt, eventually reaching its melting point. At that temperature the ice molecules become closer together and form liquid water.
Students can do an experiment to determine whether placing a piece of ice in water or air makes it melt faster. They will need a cup of room-temperature water and a similar sized piece of ice. Ask students to place the ice in the water and in the air, then measure the water levels after an hour or so and mark the results on the graph. Ask them to compare the data from each and draw conclusions about how the ice is melting.