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 cups of white vinegar
  • 4 tablespoons of baking soda 
  • a pot
  • a glass measuring cup or mason jar {heat safe glass}
  • a dish
  • a spoon
Steps:
  1. In a saucepan or large beaker, add baking soda to the vinegar, a little at a time and stirring between additions. The baking soda and vinegar react to form sodium acetate and carbon dioxide gas. If you don't add the baking soda slowly, you'll essentially get a baking soda and vinegar volcano, which would overflow your container. You've made the sodium acetate, but it is too dilute to be very useful, so you need to remove most of the water.
  2. Boil the solution to concentrate the sodium acetate. You could just remove the solution from heat once you have 100-150 ml of solution remaining, but the easiest way to get good results is to simply boil the solution until a crystal skin or film starts to form on the surface. This can take about an hour on the stove over medium heat. If you use lower heat you are less likely to get yellow or brown liquid, but it will take longer. If discoloration occurs, it's okay.
  3. Once you remove the sodium acetate solution from heat, immediately cover it to prevent any further evaporation. I poured my solution into a separate container and covered it with plastic wrap. You should not have any crystals in your solution. If you do have crystals, stir a very small amount of water or vinegar into the solution, just sufficient to dissolve the crystals.
  4. Place the covered container of sodium acetate solution in the refrigerator to chill.
  5. Once cooled you can then pretend it is water and pour it out onto a surface. It should begin to crystallize straight away and you can form towers of ‘ice’. It looks hot because it is what we call an exothermic reaction which means it gives out heat.