- plastic containers
- permanent marker
- food coloring (optional)
- two rocks for each child (granite works best)
- Epsom salt
- pictures of rocks and minerals formed from water evaporation (such as
- quartzite, aquamarine, and emerald)
- Give each child two plastic containers. Help them write, "light" on one and "dark" on the other. Ask them to put their names on their containers using stickers.
- Explain that if they add salt to the water and let the water evaporate, the remaining salt forms rock crystals. (Explain what evaporation means.) Ask the children to pour a small amount of water into each container and add food coloring, if desired.
- Ask the children to place a rock at the bottom of each container. Help them spoon Epsom salt on top of the base rock until just a little stand above the water level.
- Place one container in the dark and one in the light.
- Show the children pictures of different colored stones and explain that the salt they added to their containers will eventually look a little like the rocks in the pictures.
- Encourage the children to watch the containers each day and describe the changes they see.
- Compare the results of the containers in the dark and the containers in the light.