Science Fair Volcanoes

Vinegar & Baking Soda Volcano

This is the classic science fair project volcano. Basically, what you do is use clay, playdough, soil, or papier mache to mold a volcano around a jar or bottle. Fill the bottle most of the way full with warm water. Add a lot of red food coloring, a healthy squirt of dishwashing liquid, and a heaping scoop of baking soda. When you are ready for the eruption, pour some vinegar into the container.

Yeast & Peroxide Volcano

Form the cinder cone of your volcano just like you would for the baking soda and vinegar volcano. The difference is, fill your jar or bottle with hydrogen peroxide solution (sold at a pharmacy or grocery store). When you are ready for the eruption, pour in a packet of quick-rising yeast.

Mentos & Diet Soda Volcano

It doesn't really matter what container you use for either the baking soda/vinegar volcano or the yeast/peroxide volcano. The Mentos and diet soda volcano works best with a 2 liter bottle of diet soda, however. The candies just barely fit into the mouth of the container. To cause this eruption (which will shoot into the air like a fountain), roll a sheet of paper or index card into a tube. Stack a roll of mentos candies so they form a single column inside your handmade tube. Drop the candies, all at once, down into the 2-liter bottle of diet soda.

More Volcano Recipes

The Model

This is the classic project, suitable for younger explorers. Learn about how real volcanoes work. Make your working model as much like a real volcano as possible. Explain how the chemical volcano is like a real volcano. Identify ways in which it is different.

The Demonstration

There are multiple types of volcanic eruptions. Not all of them involve lava bubbling up from a cinder cone. The next step up from making a model of a volcano is to explain how a volcanic eruption occurs and relate this to the chemical reaction that takes place in a chemical volcano. All of the volcanoes I have listed produce carbon dioxide gas, which tries to float up from the liquid, gets caught in bubbles, and froths out of the volcano. Even though this is a different principle from how volcanoes erupt, the escape of liquids and gases from the cone is much like what happens when lava and hot gases flow.

Experiments with Chemical Volcanoes

Is there a 'best' proportion of ingredient to cause the perfect eruption? Does the temperature of the ingredients matter? Does the volume of the container make a difference? There are several variables you can control when you make a chemical volcano. You can propose a hypothesis about what will happen if you change one or more of these factors.