Construct a model volcano, mix household chemicals to represent lava, and combine this mixture with another household chemical to cause a volcanic eruption. (This works especially well outside.)

What You Need:

Baking soda - 4 tablespoons
Board - about 20" square (optional)
Dish detergent, clear - ½ cup
Jar, 1 quart (1 litre)
Jar, small (e.g. baby food jar)
Measuring cup and tablespoon
Vinegar - ¼ cup
Water - ½ cup
Food colouring, red - 1 bottle per class

What To Do:

Make a mountain shape out of dirt. If students wish to repeat the eruption, provide plaster of Paris rather than dirt. The plaster of Paris version will be more permanent. Follow instructions on box. If a group wishes to keeps its volcano, they should build it on a wooden board.

Bury a small jar in the top of the mountain just to the top of the jar. Do not cover the jar.

Put 4 tablespoons of baking soda into the small jar buried to the rim in the mountain. 

Mix the water, dish detergent and the vinegar in the quart jar. Add a drop or two of the food colour to each group's quart jar. (This recipe has enough ingredients for several eruptions.)

Pour a small amount of the mixture into the small jar in the mountain. Observe carefully the eruption that occurs. You may need to help the reaction along by stirring inside the volcano with a stick.

What's Going On?

Baking soda and vinegar, when mixed with together in a small jar, produces carbon dioxide gas. If dish detergent is mixed with the vinegar, the gas creates bubbles. If food colouring is also added to the vinegar, the substance produced looks somewhat like red-hot molten lava. The gas in the mixture forces the bubbles (lava) out of the opening of the small jar.