Chapter 13, Lesson 2, "Volcanoes"

Materials:

• Worksheet, "Volcanoes"

Objective:

• Students will explain how volcanoes form.
• Students will describe three types of volcanoes

Anticipatory Set:* Teacher will put some baking soda and vinegar in a bottle and tighten the lid on. Tell the students that under the surface of the earth as rocks melt they release trapped gasses within the rock. That gas pressure continues to increase until it breaks through the surface of the earth much like opening this bottle. What is this type of structure on earth called?

Teacher Input:* Show a volcano. Discuss what a volcano is. Show the students a second diagram of a volcano and explain the different parts of the volcano. Define volcano and vent. Where do we find most volcanoes? (Show this picture of Volcano Locations) Why is that a good spot for them? (Earth Plates) Why are Alaskan's affected more by volcanoes than Wisconsin folks? (Show Alaska volcanoes) Show the students a picture of divergent plates and explain that Japan, the Aleutian Islands formed when parts of the plate sink down under another plate and lift up as well as allow magma to the surface.

There are three different types of volcanoes based on how they erupt, the material that comes out, and the shape of the volcano. The cinder cone, has steep sides and a narrow base. It builds in layers of loose rock and dust. It can have very violent eruptions. In 1943 one of these volcanoes erupted through a crack in a corn field. This volcano grew for 9 years and then stopped erupting after it was over 1000 feet high. (Paricutin). The shield volcano is much lower and has a broader base. It is not very explosive and has a very wide crater. The lava flows slowly then cools blocking the lava behind it. the lava then alters its path continuing to cool and harden to form the outer ridge.It can build a huge mountain in fact, this one Mauna Loa in Hawaii is higher from top to bottom than Mt. Everest it just starts below sea level. Composite volcanoes have calm eruptions that alternate with violent eruptions. The violent eruptions throw large rocks into layers around the edge of the volcano and the calm eruptions add thin layers of lava that tie the layers together.

Ask, "What type of volcano did we demonstrate at the beginning of class?" (Could be any of them depending on how violent it exploded)

Compare and Contrast Shield, Composite and Cinder cone volcanoes with a venn Diagram.

Guided Practice:* Students will answer the questions on page 316. Each site will take one.

Independent Practice:* Students will complete the worksheet, "Volcanoes"

Check for Understanding:* Students will take the quiz on Section 2, "Volcanoes"

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).

Alaska Content Standards Addressed in this lesson:

• SCI A-1 Students will understand models describing the nature of molecules, atoms, and sub-atomic particles and the relation of the models to the structure and behavior of matter (Structure of Matter);
• SCI A-3 Students will understand models describing the composition, age, and size of our universe, galaxy, and solar system and understand that the universe is constantly moving and changing (Universe);
• SCI A-7 Students will understand how the earth changes because of plate tectonics, earthquakes, volcanoes, erosion and deposition, and living things (Processes that Shape the Earth);

• SCI A-15 Students will use science to understand and describe the local environment (Local Knowledge); and: