Snow-melting experiments provide a tangible way for young children to understand the basic concept that snow, though solid, is actually water -- a liquid -- in a semi-frozen state; its state of matter is dependent upon temperature. Demonstrating this concept involves a few snowballs and a couple glasses of water. Have children form snowballs small enough to fit inside the glasses. Fill one glass with ice cold water, one glass with warm -- but not hot -- water, and one glass with room-temperature water. Have children describe the temperature of the snow as they form it into balls. Ask them to place a finger inside each glass and describe the varying temperatures of the water inside, encouraging them to describe similarities and differences between the temperatures of the water and that of the snow. Ask children to make predictions about which water temperature will melt the snow, transforming it into a liquid state, the fastest, then drop the snowballs in each glass. When the snowball in the warm water melts first, discuss why warmer temperatures melt snow faster.
Snowballs make a fitting experiment item for explaining the concept of ambient air temperatures and their subtle fluctuations. Instruct children to make several snowballs and then place them inside plastic bowls or cups around different areas in the home or classroom such as a sunny windowsill, a dark closet, a cold hallway, near a radiator, on the floor near a drafty door or under a desk lamp. Using a watch or clock, keep track of how long it takes each snowball to melt and record the times on a chart or blackboard. Once all the snowballs have melted, discuss the results, explaining the differences in temperature among each location, the effect warm and cold temperatures had on the snow and what factors might be responsible for the different temperatures.
Melting snow with salt teaches young children about the basic principles of molecules and chemical reactions. Discuss the use of rock salt, encouraging the children to describe instances when or where they've seen it used. Allow them to look at and touch a sample of rock salt that is sealed inside a plastic sandwich bag. After the discussion, place a small pile of snow in two dishes. Sprinkle one with the rock salt. Record the amount of time it takes each dish of snow to melt. Once both dishes are completely melted, discuss how and why the salted dish melted faster.
To test different melting rates of snow, provide children with a small bowl of loose snow and different materials such as aluminum foil, plastic wrap, washcloths, paper, nylon stocking and wool. Have children make small snowballs and wrap them inside each material and place them in small bowls. Instruct children to observe the order in which the snowballs melt. Once all the snowballs have melted, discuss the insulating properties of each material, considering factors such as thickness, softness and absorbency when determining why the snow melted at different rates when wrapped in different materials.