We put a piece of black construction paper in the freezer after breakfast. When Norah went out to play in the falling snow, she took the paper and a magnifying glass to look at the snowflakes that fell on her paper. In her words, "One looked like a star. Another looked like a flower. I could see right through them. It was awesome!" Note: The paper didn't seem that cold to me, even after more than an hour in the freezer. So it seems that as long as the snowflakes don't just melt when they hit it, the paper doesn't have to be frozen.