Question: how are explotion created

Vince Hall answered on 17 Jun 2013:

Explosions can caused by things called exothermic reactions. These are chemical reactions that give out more heat than the take in (like stuff that burns). (Reactions that take in more heat than they give out are called endothermic reactions.)
You need lots of energy, like heat, and things that will burn, the fuel, and usually air, particularly oxygen.

When a volcano explodes, that is because the energy contained inside the Earth is released. The middle of the Earth is already hot, it doesn’t need oxygen to burn things.

Once you have an exothermic reaction, you need a contained space, so the pressure can build up to huge amounts while the reaction is happening. Eventually the container will burst, and stuff will shoot out. If the container bursts in many places, bits of it will fly in every direction, and you have an explosion.

So in short, you need:
energy
fuel
oxygen(for chemical reactions)
containment(usually)
There are other types of explosions that need different things too, but this is a good start.

There is a class of explosion that doesn’t need all of these, stars.
Stars are essentially explosions that take millions or billions of years to finish. They are caused by gravity pulling all the matter in space together. The matter gets really hot, and it lets off lots of energy. Stars don’t need oxygen or containment. That’s because they make their energy using nuclear fusion; smashing two atoms together until they make just one, larger atom. This changes some of their matter into energy, and that releases vast amounts of energy!
E=m(c squared) or E = mc^2 means you can make energy from matter.
(Stars are awesome from my point of view.)