Download volcanoes stations

NAME: ____________________
PERIOD: __________________
VOLCANOES NOTES & STATIONS
The purpose of this activity is to introduce you
to the processes that create volcanoes, why
there are different types of volcanoes and
eruptions, and the rocks that can result from
volcanic eruptions.
STATION 1 (SMARTboard)
I. HOW DO VOLCANOES FORM?
1. Near what type of plate boundary
do volcanoes occur?
2. What are the processes that result in the creation of a volcano based on the picture (above)?
3. Describe the location of subduction-generated volcanoes in relation to the trench, continental
plate and oceanic plate.
II.VOLCANIC ERUPTIONS-Go the linked page on the SMARTboard to answer the
questions/definitions
4. What causes an eruption?
5. Define the following terms, all of which may result from an eruption:
 Pyroclastic flow –
 Eruption (ash) cloud Lava Lahar1
STATION 2
III. TYPES OF VOLCANOES-laptops animation
6. Use the tutorial to read about the different types or just build your own and see what types
you make!
TYPE
SKETCH GENERAL
SHAPE
SIZE
HOW THEY ARE MADE
STRATOVOLCANO
CINDER CONE
SHIELD VOLCANO
7. If you haven’t already, click on "Build your own volcano and watch it erupt." Underneath the
words "gas and viscosity settings" there is a link labeled "viscosity info." Click on it.
8. What is viscosity?
9. Experiment and then answer the following questions:
a. What effect does viscosity of magma have on an eruption?
b. What effect does the amount of gas in magma have on an eruption?
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STATION 3-Past and present eruptions, a demonstration!
IV. A REAL VOLCANO: MT. ST. HELENS
Before the eruption
After the eruption
10. Based on the pictures you see above, is Mt. St. Helens:

A stratovolcano, cinder cone, or shield volcano? WHY?

Does it have very viscous lava, or easily flowing lava? WHY?
11. Look at the aerial photos below of Mt. St. Helens and the models made from topographic
maps:

Assume the picture is oriented properly with North at the top. In which direction did the
majority of material in the eruption flow? Why do you think this?
(Station 3 continued)
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12. a. What type of volcano does the one we erupted in class represent? Why?
b. What type of magma erupts from these and where in the world is an example?
STATION 4-rocks made by magma and lava
V. IGNEOUS ROCKS
13. After looking at the samples, sketch the crystal sizes of each in the boxes below. Based on the picture
of where each of these formed, fill in the blanks below for each sample with (cooled) quickly or slowly or
quickly and slowly, large or small or large and small (crystals). Texture information is on the next page.
hardened lava
cooled _________________
______________________crystals
________________________ texture
hardened pyroclastic flow
hardened magma chamber
cooled ____________________
cooled _________________
_________________________crystals
__________________ crystals
______________________ texture
____________________ texture
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VI. TEXTURE
14. What does it mean when geologists refer to an igneous rock's "texture?” (use the reading
below)
15. With the vocabulary listed below, label the pictures you drew above as "fine-grained
texture," "coarse-grained texture" and "porphyritic texture."
16. Obsidian is a glassy igneous rock (check out the sample!). Where do you think obsidian is
formed? Why?
Texture Reading:
The grain size of crystalline igneous rocks can be separated into three broad categories.
Coarse-grained igneous rocks have individual grains (crystals) that are visible to the naked eye. Grains
can range from millimeters to centimeters in diameter. The grains form an interlocking network.
Fine-grained igneous rocks have small grains, less than a millimeter across, that are invisible to the
naked eye. Hand samples of fine-grained rocks often appear homogeneous—they look the same
throughout the rock. Hand lenses, magnifying glasses, or microscopes can reveal the small crystals in
these rocks.
Igneous rocks with a porphyritic texture show two distinct grain sizes—coarse-grained crystals, visible
to the naked eye, surrounded by fine-grained crystals.
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