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Spot on Science: Volcano Vocab

Turns out lava on the ground isn't necessarily the biggest danger of volcanoes. Margaret whizzes through a ton of volcano vocabulary, explaining what makes volcanoes so scary.

Class Discussion Questions:

1) Compare and contrast lava and magma.

2) Create a biographical baseball card for each of the types of lava.

3) Create a caution sign for two pyroclastic materials.

Read the Script:

Anyone ever play "the floor is lava"? Always a fun time! But, when a real volcano explodes, it turns out, there's a lot more to be afraid of than just the lava on the ground. 

Let's start at, well, the start. There's hot molten rock beneath the earth's surface, called magma. It can range in temperature from about 570 degrees Fahrenheit, which is actually how hot you might cook a pizza, all the way up to 1600 degrees, which would basically incinerate your pizza. 

So when enough magma builds up, it will push through the volcano's conduit, or main passageway, and break through the vent, or opening in the top or crater of the volcano. Did you catch all those terms? Conduit, vent, crater. Good, 'cause this is where it gets interesting. 

As soon as the magma reaches the earth's surface, it's name changes to lava. As if that weren't confusing enough, there are different types of lava, named based on how they flow from a volcano. 

Pahoehoe lava moves slowly, and results in a smooth surface with rope-like ridges. Then there's AA lava, that's kinda chunky, and flows quickly, leaving a jagged surface behind. Now, even though AA flows quicker than pahoehoe, in most cases, it can still be outrun and, sometimes, just out-walked by humans. 

What's harder to escape is the lava that flies instead of flows. Lava that gets tossed into the sky is called a pyroclast. And, of course, pyroclast have their own categories too. Tiny bits of lava make up volcanic ash. This is what you see billowing from the top of a volcano. 

Ash is often mixed with poisonous gasses to form volcanic smog, or vog. it can be dangerous to breathe and can irritate your eyes. Plus, depending on the wind, it's difficult to escape. 

This is not to be confused with laze, the toxic haze that's released when lava hits the ocean. This steamy mixture contains poisonous hydrochloric acid. 

Bigger pyroclasts, called volcanic bombs, or lava bombs, are also super-dangerous. I'm sure you can figure out where the name comes from. These sometimes bolder-sized pieces of lava can cause serious damage. 

There are still even more types of lava and pyroclasts, but to keep your brain from spinning, we'll stick with those. So, yep, lots of confusing terms, but we're talking about volcanoes, and I'm okay with that.