A states of matter activity teaches kids about how icicles are made from liquid water and turned into solid ice. One important lesson to emphasize about states of matter is that the chemical properties of water remain the same, regardless of whether the water is frozen or a liquid. Another important scientific concept is the relationship of temperature and the states of matter. For instance, cold temperatures freeze ice and warm temperatures melt it. This phenomenon can be demonstrated as part of the icicle lesson. One idea is to have each kid made his own icicle out of a cone-shaped mold that is filled with ice and placed in the freezer overnight. Another way to demonstrate the origin of icicles is to fill a plastic bowl with water, stick it outside in freezing temperatures and check on it the next day to find it frozen.
Icicles form downward, starting at a wider base and ending at a point that faces the floor. For a kids' lesson about the direction that icicles form in, you can discuss concepts such as gravity, and explain that this is what makes water drip from a roof or other structure. The end result is that the water dripping eventually freezes, causing the icicle to begin to form. This lesson may lead into a discussion about where icicles are found, such as on rooftops, shingles, window frames and trees. Basically, icicles must form from above in order for them to get their long, straight shape.
The origin and formation of icicles can be explained through a lesson about the water cycle. In the water cycle, liquid water in the form of oceans, lakes, rivers and other water reservoirs is evaporated and turned into water vapor. The water vapor rises and condenses to form clouds and then the water is released through precipitation, such as water or snow. Then the cycle starts over again. Icicles are formed at the last stage of the water cycle, when the snow, or precipitation, makes its way onto rooftops or trees and turns into an icicle. Once the icicle melts, this completes the cycle because the water goes back to being a liquid and can turn into water vapor.
Icicles have scientific relatives, known as stalactites. During a lesson about icicles, introduce kids to stalactites so that they understand the differences and similarities. For instance, one thing icicles and stalactites have in common is water. Water forms icicles and water is also responsible for containing minerals that react with calcium carbonate, or limestone, to create stalactites. Icicles and stalactites both grow downward and have similar pointy shapes. Icicles and stalactites are different, however, because icicles are made purely out of water and stalactites are made from minerals and grow in limestone caves.