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How to Make Stalactites at Home

Stalactites form from the ceilings of caves and are made from calcium deposits. Calcium water drips from the ceiling, evaporates and leaves the calcium behind to form stalactites. This same process can be recreated at home to make your own stalactites by using salts instead of calcium. This project is an appropriate scientific lesson plan for fourth through eighth grades, but can be a fun learning experience for people of all ages. Learning how to make stalactites at home can also be a creative after-school or summer break project.

Things You'll Need

2 glass jars
Epsom salt
Newspaper
2 nails
Yarn

Instructions

- 1
  
  Glass jars are sturdier than plastic cups.
  
  Fill both jars with hot tap water up to 2 inches from the rim. Stir Epsom salt into each jar to thicken, and keep adding salt until it will no longer dissolve. Spread newspaper onto a flat surface in a low-traffic area.
- 2
  
  Cotton or wool yarn can be used to make stalactites.
  
  Situate both jars onto the newspaper, leaving a 6-inch gap between the jars. Tie a nail to each end of an 20-inch piece of yarn and saturate the yarn with the salt solution. Place the nail of one end of the yarn into each jar. Allow the yarn between the jars to drape a couple of inches below the rims of the jars.
- 3
  
  Salt causes stalactites to form on the yarn and creates formations in the Dead Sea.
  
  Do not disturb the project. Check the yarn each day for four days until you see a formed stalactite below the sagging portion of the yarn.

Rocks & Minerals