How to Make a Volcano. Make a lava-spewing volcano as a science project or just for fun. If you have children, let them help you because this is something the whole family can make together. So gather up are the material you need and start building your very own volcano.
Use a sheet of plywood at least 8 inches wider and longer than your planned volcano to make the base, to prevent the lava from staining surfaces during eruptions.
Use salt dough, plaster or papier-mâché to form a mountain around an empty 2-liter bottle placed upright at the center of the plywood base. Be sure to leave the lid off.
Form the model volcano's open top tightly around the mouth of the bottle.
Make ridges and channels beginning at the volcano's top and ending at the base of the volcano for the lava to flow through.
Let the volcano dry completely, then paint it with acrylics or spray paint. Plastic aquarium plants can be clipped and glued to the volcano for trees.
Spray the volcano and plywood with a clear sealant after the paint has dried.
Mix 1 tbsp. liquid dish washing soap, 1 tbsp. baking soda and a few drops of red food coloring in a cup.
Pour the mixture carefully into the bottle.
Set the volcano in an open area, preferably outside.
Pour 1/4 c. white vinegar into the bottle and stand back to watch your volcano erupt!
Use wadded-up newspaper balls around the bottle to give the volcano its shape under a layer of plaster or papier-mâché paste, but make sure the surface layer of the volcano is solid, so that it can be sealed for re-use. If the lava is too thick, add 1 tbsp. water to the soap mix. To re-use the volcano, simply clean it off with a damp rag. With drying time, making a volcano is at least a two-day project.
Do not attempt to seal the bottle once the vinegar is added to the baking soda mixture--the resulting pressure could cause the bottle to explode.