Materials
several containers with lids
deep buckets or plastic tubsInstructions
1. Make ice crystals indoors. Fill several containers with hot water. Put tightfitting
lids on the containers and place in a freezer overnight.
Condensation of the hot water vapor will coat the underside of the lids.
This will freeze as delicate crystals, while the water in the bowl will form a
solid block of ice.
2. Carefully remove the lids and encourage the children to examine the
crystals. They will melt very quickly, so it is helpful to freeze several bowls
and open just one or two at a time.
3. Discuss how these crystals compare with snowflakes. (They will be
mostly needle-like or feathery structures.)
4. If possible, make ice crystals outdoors. Fill deep buckets or plastic tubs
with water. Place outside in subfreezing temperature.
5. When the water has partly frozen, carefully remove the thick cap of ice
from the top of the container. (This may take 1/2 day to 2 days, depending
on outside temperature and size and shape of container.) Encourage the
children to observe the ice crystals hanging from the underside of this
ice block. (These will be larger than the ice crystals formed in the freezer.)