Computer animation and real images of eruptions will introduce volcanoes to you.
From space, the Earth looks to be a peaceful place. Look more closely and you find out that it is not. The inside of the Earth is very hot indeed and this heat needs to escape somehow. Molten rock travels up from inside the Earth, exploding out at the surface as volcanoes. We call this molten rock ‘magma’ before it reaches the surface and ‘lava’ when it comes out of the volcano.
Some volcanoes throw out massive clouds of ash that rise high into the air. The ash particles bump into each other and the friction between them creates huge amounts of static electricity. When enough static electricity builds up in the ash cloud, you get lightning, just like with thunder clouds.
Sometimes these ash clouds flow down the slopes of the volcano instead of going into the air. They are very destructive as they are extremely hot (many hundreds of degrees celsius). Any living material they touch is immediately burnt to cinders. Nearly 2000 years ago, an ash cloud like this destroyed the Roman city of Pompeii. Most of the inhabitants did not even have time to even try to escape. Any who were not killed by the heat would have been suffocated by the ash.
Other volcanoes emit molten rock which can be thrown tens or even hundreds of metres into the air as ‘volcanic bombs’. But some lava is very runny and travels down the slopes of the volcano as a fast moving red hot river of magma, bubbling and boiling on its journey, destroying anything in its path.