The most powerful force in nature is volcanic activity. Some volcanic eruptions are more powerful than the largest nuclear explosion.
According to the theory of plate tectonics, the earth’s crust and upper mantle are made up huge, rigid slabs called plates. The plates are all moving in different directions at different speeds. When they crash together, pull apart or sideswipe each other, the resulting friction can cause earthquakes or volcanoes near the edge of the plates.
When one plate overlaps another, often the extreme heat at the centre of the earth will cause the lower piece to melt. It will form magma, which is molten rock deep in the earth. The extra pressure forces the magma to rise. The magma, dust, and gases push up through the opening in the earth’s crust and form a mountain. A violent explosion can cause the top of the mountain to blow off, leaving a deep crater. When the magma reaches the surface and emerges from the volcano, it is called lava.
A realistic model of an active volcano may be constructed as follows:
6 cups flour
2 cups salt
4 tablespoons cooking oil
An empty pop bottle or small tin can
A large pan or plywood board on which to construct the volcano
2 tablespoons of baking soda (NaHCO3)
1. Make the volcano cone first. Mix 6 cups flour, 2 cups salt, 4 tablespoons of cooking oil and 2 cups of water. The mixture should be smooth and pliable, like dough. More water may be added if necessary.
2. Place the pop bottle or tin can on the plywood, or in the large pan. Shape the dough-like mixture around it so the structure resembles a volcano. Add twigs or greenery around the base and sides for realism, if you wish.
3. Fill the bottle or can of the way up with warm water. Add a bit of red food colouring.
4. Add a squirt of detergent to the mixture.
5. Add 2 tablespoons of baking soda to the mixture.
6. Slowly pour about 1/2 cup of vinegar into the mixture.
A chemical reaction takes place between the baking soda (a base), and the vinegar (an acid). In this reaction, carbon dioxide gas is produced, as it is in an actual volcano. Pressure builds inside the bottle or can. You will see frothy red “lava” bubble out of the “volcano”.
Baking soda (base) + vinegar (acetic acid) = carbon dioxide + water + sodium acetate
In chemical terms, it is written as follows:
NaHCO3 + CH3COOH = CO2 + H2O + CH3COONa