Make Your Own Stalactites and Stalagmites

Both stalactites and stalagmites are rock formations that form on the ceilings and floors of caves.

They form when water drips from the cave ceiling over thousands of years. Both have a tapering shape that is larger at the base and form a point.

Stalactites hang from the ceiling of a cave and are formed from mineral deposits left behind from slowly dripping water.
Stalagmites grow in the same way, but forms from from the cave floor upward. As the water drips from the ceiling above the two are formed simultaneously.   Make your own with this cool experiment!
Materials Needed:
  • 4 Glasses or Jars
  • Cotton String (or other absorbent string/yarn)
  • 4 Large Paper Clips
  • Epsom Salt
  • Baking Soda
  • Hot Water
  • Tray
Steps:
  1. Fill the jars with hot water. Two of the jars will be for the salt water solution and two of the jars will be for the baking soda solution. In each jar mix in as much salt or baking soda as you can. When it stops dissolving in the water, you have enough.
  2. Cut 2 long pieces of string. If it is thin, then do three strands thick. It is preferable to use cotton string or yarn as it is more absorbent than synthetic materials.
  3. This string will absorb the water from the jar and allow the water to drip down. It will act like the formations found in caves leaving behind the minerals- either baking soda (sodium bicarbonate) or salt (sodium chloride).
  4. Tie large paper clips, or other objects to the end of the strings to weight them down in the jars. Put the string in each jar. Connect the two jars of baking soda together with the string hanging down in the center. Do the same with the two salt water jars.
  5. Make sure to place a large tray underneath to collect all of the mineral deposits.
  6. Now you leave it and just observe it each day. For best results, leave it for 3 weeks. There were a few times when the water level gets low and so you can  add more of the solution to the jars so it could continue to grow.