Ice melting is the process of ice and snow breaking down into liquid water. Melting glaciers and ice sheets release freshwater into oceans, influencing ocean temperatures, and impacting global climate. Ice melt is a result of many factors, including warming air and sea water, the amount of sun exposure, the location of the ice, and even the composition and structure of the ice itself.
A key factor in melting glaciers is water that bores through the ice, making its way through the ice sheet and absorbing heat at the bottom of the ice. As the water gets warmer, it begins to flow faster. This creates pressure underneath the ice and causes it to melt. This is what we observe in leads and polynyas, where warm surface waters push up against ice edges.
As the ice continues to melt, its orderly crystal structure collapses and water molecules move past each other. This movement overcomes their natural attraction, and they begin to actually get closer together as they liquefy. This is the melting point, the temperature at which ice turns from solid to liquid.
Students can experiment with how quickly ice melts by testing the time it takes for an ice cube to melt in different conditions. This activity can be done in small groups or one at a time, and is a great way to help students build their skills of measurement and observation. Using a pitcher of room-temperature water, students can compare how long it takes for an ice cube to completely melt under each condition. Students can also use a bucket of water with varying levels of heat to demonstrate the effect of hot and cold water on the melting process.