Volcanoes
Volcanoes are like mountains filled with ash, magma, smoke, and lava. But if thats all they are to you, you are wrong. There are 3 types of volcanoes and here they are: shield volcanoes, cinder volcanoes and composite volcanoes. Mostly all volcanoes in the world sit around the Ring of Fire on the Pacific plate. Now you may think why is it happening around that plate? Well, the North American, Eurasian, and Australian plates are all crashing and colliding with the Pacific plate. This action is forming a convergent boundary and along with a convergent boundary comes a subduction zone. At the subduction zone, the plates crumble and build a volcano. It can take 5,000 to 100,000 or more years for a volcano to build it's self.
Shield Volcanoes
Shield volcanoes are one of three types of volcanoes. They are made of layers of hot lava. It occurs on divergent boundary hot spots. This volcano is mostly found in Hawaii. Shield volcanos don't explode, they ooze and have very gentle slopes.
Cinder Cone Volcanoes
A cinder cone volcano is made out of fallen ash. They have straight steep sides and a bowl shape. It violently explodes ash.
Composite Volcanoes
Composite volcanoes are made of ash, hot lava and cinder. They are steep up top and more gentle around the bottom. They have a cone shape and are symmetrical. They explode and ooze. They are located on convergent boundaries.
The video is bill nye explaining more on the connect of volcanoes.