A simple interactive project can teach younger children about how volcanoes are formed by layers of lava and pyroclastic flows, hot ash and gas. The children fill small cone-shaped paper cups with orange modeling clay. This is turned upside down on a paper plate and represents the magma chamber. The children then build up alternating layers of orange clay -- to represent the lava layers -- and purple clay -- to represent the pyroclastic layers. When the children are done, use a sharp knife to cut the models in half from the tip top to the paper plate so the children can see the buildup of layers.
A classic explosion project provides a visual example of what a volcano eruption looks like; it is appropriate for younger children. First the children build a clay volcano around an Erlenmeyer flask using clay, or material from the environment around them. The volcano should be made in a container --such as a baking dish -- to catch the overflow from the experiment. Baking soda is scooped into the opening of the flask; when vinegar is poured on top of the baking soda the reaction will take place.
An elementary carbon dioxide project can demonstrate the role of carbon dioxide gas in a volcano eruption using diet soda and Mentos candy. This experiment is best done outside. Children can build up soil or sand around an unopened 2-liter bottle of diet soda.
A roll of Mentos is stacked in a test tube and an index card is placed over the opening of the test tube. The bottle of soda is opened and the test tube of Mentos is placed upside down -- so that it lines up with the opening of the soda bottle with the index card creating a barrier between the Mentos and the soda. The index card is quickly removed so the Mentos slide into the bottle all at once; the reaction takes place very quickly.
An ammonium dichromate volcano is an advanced project for older students with experience with chemistry who have the supervision of a teacher with a chemistry background. In the experiment the ammonium dichromate ignites and breaks down in an exothermic reaction which resembles a volcano because it sparks, creates a large volume of green chromium oxide "ash," steam and nitrogen gas. It is performed by pouring 3 g of ammonium dichromate into a pile in the center of a conical flask.
To prevent loss of chromium oxide powder during the reaction, wool material is placed over the opening of this flask. The flask is heated on the blue tip of the Bunsen burner flame. The orange solid sparks when the reaction begins and then it breaks down into a green flaky substance. At this point the flask is removed from the flame and placed on a heatproof mat. There may be traces of unreacted dichromate dust in the residue after the reaction so gloves should be worn when transferring or sweeping up the residue of the experiment into a plastic bag.