Experiments & Activities
Grades K - 4 "Crystal Growing Experiment"
A crystal growing experiment can be a great demonstration of how speleothems grow. Included in this lesson plan is an experiment that can be adapted for the K - 4 grade levels. In addition, students can do a simple sugar crystal growing experiment, or grow popcorn rock (kits are sold in our Nature Gift Shops).
• Explain how layer upon layer of the material continues to deposit in the same place, creating the "growing" effect.
• Growing two experiments simultaneously gives you the opportunity to use one as an example of how humans can destroy formations by a single touch. Allow a few students to handle the crystals and see what happens.
Grades 5 - 8 "Crystal Growing Experiment"
Materials
- 2 pieces of 12-inch cotton yarn or string (cotton yarn wicks liquid better than acrylic yarn)
- 4 jars of the same size
- 2 saucers
- washing soda (sodium carbonate) (substitute Epsom Salts if washing soda is unavailable)
- baking soda (sodium bicarbonate)
- warm water and mixing container
- student worksheets, included
- optional: magnifying glass, pictures of speleothems
Procedure
Explain to the students that this experiment will show how water can deposit minerals to create cavern formations, also known as speleothems. Explain that this process in a cavern takes thousands of years. The students will be creating their formations by using a salt-based chemical compound. This will speed up the process by using concentrated solutions and the sun's help in evaporation.
