Download Volcanoes - Mrs. Pechan`s Class!

A Lesson about
Volcanoes
WHAT ARE
A volcano is an opening exposed on the earth’s surface where volcanic
material (or magma—molten rock) is emitted. The volcanoe’s coneshaped structure is build by the accumulation of lava around it’s summit.
There are many types of volcanoes. Here are some examples below that
demonstrate the various shapes and sizes.
Volcanoes are all shapes and sizes, as we’ve seen earlier.
Did you know they can be flat as well?
Yes, volcanoes that are newly formed are flat.
The build-up of lava over a long period of time is what creates the conelike shape.
Question: Are volcanoes only on land? Can volcanoes exist under water
like in the ocean? Take a few minutes and write your thoughts in your
science journal. Then discuss with a partner.
So, can volcanoes exist in the ocean? YES! As you can see, volcanoes
exist on land AND in the ocean. Now, how do you think volcanoes are
formed?
Volcanoes occur because the Earth’s crust is broken into plates that
resemble a jigsaw puzzle. There are 16 major plates. These rigid plates
float on a softer layer of rock in the Earth’s mantle. As the plates move
about they push together or pull apart. Most volcanoes occur near the
edges of these plates.
When plates push together, one plate slides beneath the other. This is
called a subduction zone. When the plunging plate gets deep enough
inside the mantle, some of the rock on the overlying plate melts and
forms magma that can move upward and erupt at the Earth’s surface.
Some volcanoes can occur in the middle of plates at areas called
hotspots—places where magma melts through the plate and erupts.
Why do volcanoes erupt?
Deep within the Earth it is so hot that some rocks slowly melt and become a thick
flowing substance called magma. Because it is lighter than the solid rock around it,
magma rises and collects in magma chambers. Eventually some of the magma pushes
through vents and fissures in the Earth's surface. A volcanic eruption occurs! Magma
that has erupted is called lava.
The volcano erupts!
Hot magma rises to the
surface
Deep in the
Earth’s core is
where magma is
formed
LAVA
What is lava? Lava is the magma that has risen to the surface and is
expelled by the volcano. Below are some different types of lava.
Aa lava
Block lava
Pahoehoe
Let’s Review!
1. What are volcanoes?
2. Why do volcanoes erupt?
3. What is magma?
4. What makes a volcano?
5. Where do volcanoes exist?
6. What is lava?
7. What are some types of lava?
8. Now…
Let’s draw our own volcano!!
*Arts and crafts activity. Draw your own picture of a volcano and
write a story about it!*
Volcano activity!
*Science lesson! Create a volcano right in your own classroom!*
I sure hope you have enjoyed this wonderful and exciting lesson
about volcanoes! Please ask your teacher to press PLAY on the
VCR to watch a great movie about volcanoes and see some
beautiful pictures of real live volcanoes!