Paper mache volcanoes are popular children's science and craft projects. The volcanoes are typically made out of newspaper and paper mache paste. A fun part of building these miniature volcanoes is making them erupt. The eruption can teach children about the reaction that occurs when vinegar and baking soda combine. It also makes the project more realistic.
Most paper mache volcanoes can be constructed at home using common household ingredients. To make the paper mache paste, a person can combine one part flour with two parts water or one part glue with two parts water. An empty plastic water or soda bottle forms the center of the volcano while strips of newspaper or tissue paper are dipped into the paste and spread around the bottle, eventually making a mountain shape. Some people choose to stuff the volcano with crumpled newspaper to make shaping it easier.
The paste should dry overnight. After the paper mache paste dries, children or students can paint the paper mache volcanoes to make them look more realistic. Some people place the dried and painted volcanoes on a cardboard or plastic tray to prevent the "lava" from spilling everywhere.
A key part of building paper mache volcanoes is combining white vinegar with baking soda to make the volcanoes erupt. The vinegar is poured into the bottle in the center of the volcano. Some people mix in a few drops of red food coloring to make the lava look authentic. A good amount of baking soda is then poured into the bottle on top of the vinegar.
As baking soda is a base and vinegar is an acid, the two ingredients react when they come into contact. The baking soda–vinegar mixture bubbles up out of the bottle and down the sides of the volcano. It looks as the volcano is erupting. Although combining baking soda and vinegar doesn't demonstrate how volcanoes actually erupt, it does introduce students to basic chemical reactions.
Constructing paper mache volcanoes is an ideal project for younger children. It can be done in a classroom setting with grade school or early middle school students. In class, the volcano models are often accompanied by some instruction about the composition of the Earth and how eruptions occur. As paper mache is easy enough to make with household items, making volcanoes at home is a simple project to engage and occupy children on days off from school.