Wax Volcano Demonstration – A Realistic Model Volcano

This wax model volcano illustrates many of the processes that occur in real volcanoes.
This wax model volcano illustrates many of the processes that occur in real volcanoes.

This wax and sand volcano is a realistic model volcano that is easy to make and erupts much like a real volcano. The volcano is extremely simple to make and interesting to watch. Wax “lava” forms a volcano in sand, eventually erupting into the atmosphere, which is water in this model. You can experiment with the amount of wax, quantity and type of sand and intensity of heat to form different types of volcanoes.

How It Works

A real volcano forms and erupts because molten rock (magma) and hot gases push up from the Earth’s mantle into the crust. This material pushes up through the weakest spot in the crust to be released as an eruption. This wax volcano in a cup works very much the same way. Wax in the bottom of the cup is heated and becomes molten.

Wax Volcano Materials

The materials needed for the wax volcano are inexpensive and easy to find:

  • candle (wax) – try red or orange wax for realistic lava
  • sand
  • water
  • heat-safe clear glass cup or glass

Make the Wax Volcano

  1. Light the candle (or otherwise heat the wax) to drip wax into the bottom of the cup.
  2. Cover the wax with a layer of sand. The thickness of the wax and sand layers will affect the way your volcano erupts. If you have a thin sand layer, the wax will readily rise up through it. On the other hand, if you have a thick sand layer, the wax will have a harder time erupting through the sand. Thicker layers will produce a more cone-shaped volcano, but you may need to apply more heat to get an eruption or the “magma” may be unable to erupt.
  3. Gently heat the bottom of the cup. You have a few different options for doing this. You can heat the glass over low heat directly on a burner on a stove or hot plate. Don’t apply too much heat or raise the temperature too quickly or else the cup may shatter! A safer (though slower) method is to set the cup in a shallow pan of water. The water will offer protection for the glass. Either way, heat the cup until your volcano erupts.
  4. This project is repeatable. After your volcano erupts, turn off the heat and let the cup cool. Remove the sand and wax from the cup. You can re-attach the wax to the bottom of the cup by melting a few drops of wax into the cup. Stick the other pieces to the melted spot. Add sand and water and try again.

Watch a Wax Volcano Erupt