Pelean eruptions give off pumice and glowing rocks. In Plinian eruptions there is a violent explosion of gas and thin, fast moving magma. Hawaiian and Strombolian eruptions cause a line of magma fountains. The lava is very fluid. When magma reaches the ocean, pillars of rocks are formed.
Volcanoes can also do some good things too.
They give off natural resources, such as volcanic rock, gas, steam, pumice, boric acid, ammonia and carbon dioxide. In some places, like Iceland, volcanoes heat the water for the people who live there. Geothermal steam is exploited as a source of energy for the production of electricity all around the world. Volcanoes are a lot of fun, and interesting, to study because they give us many natural resources, but they are also very dangerous. Volcanoes are really cool.