Young children are savvy observers -- your preschooler has probably already noticed changes in your family's habits and behavior as the weather gets cold. We start wearing gloves, hats and coats, and we walk more carefully in the snow. Has your child noticed clouds of his or her breath in the frosty morning air? The molecules of water vapor in our warm breath lose their heat energy in the cold and condense to a fog of tiny liquid water droplets. When liquid water loses even more energy, it turns to ice and snow.
The seasonal changes occurring at this time of year are a great opportunity for preschoolers to practice their science skills of observing, comparing and predicting changes.
On a snowy day, ask your child to fill two large bowls with snow and bring them inside. Put one bowl in the freezer and leave the second out. What does your child predict the difference between the two bowls will be throughout the day? After the snow melts, you might notice that a big pile of fluffy snow left only a small amount of water. As the frozen crystals of water gained energy in your warm home, they melted into a liquid. If you have a bowl in the freezer, how much snow is left?
Once the snow is melted, ask your preschoolers what they think will happen if you put the bowl back outside. Do they think it will turn back into snow? If the temperature is below freezing, check your bowl often to observe the changes. You might first notice a thin layer of ice that breaks easily, then a thicker layer that floats on the water. Finally, the water molecules will lose enough energy to freeze to solid ice.
While the snow is here, don't forget to pop a snowball into your freezer for snowball day at Carnegie Science Center in the summer.