Business

Lesson Plan 7

Magma

Discuss

Why don’t all volcanoes look and act the same?

What shapes can volcanoes be? (revisit photos if necessary) - Cone shaped -Ruapehu, Taranaki, Rangitoto, White Island, Ngauruhoe - Crater (caldera) shaped-Taupo & Rotorua - Fissures- Tarawera, ocean spreading ridges (including Iceland) - Domes-Tarawera and many others in Taupo Volcanic Zone - Other shapes- Dunedin &Banks Peninsula- eroded and flooded shield volcanoes, Rangitoto-shield with a summit cone What are possible reasons to explain the different shapes and sizes? - Different ages meaning different amounts of erosion - Different numbers of eruptions, more eruptions build higher, more complex,cones. - Different types of eruption leave different things behind - Volcanoes with vegetation don’t erode so fast. - Different sizes of eruptions, some more violent than others How are Auckland’s cone volcanoes different to those in the TVZ? - Smaller, less volume erupted, more of them, also some craters (eg Pukaki) caused by explosions

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Learning Intentions

• To see that different types (shapes) of volcano are created by different types of magma leading to different types of eruption. • Observe the flow of different liquids and compare their viscosity. • Observe what happens to gases in a liquid under different pressure conditions

Success Criteria

Students can • Complete the worksheet accurately. • Describe the properties of magma, using appropriate words such as viscosity and pressure, and concepts such as the expansion of gases.

Explain

Different types of magma cause different types of eruptions and create different sorts of volcanoes. Magma contains molten or partly molten rock and dissolved gases such as water.

Activity

To find out how gases behave discuss and observe: What is in the bottle of fizz? Water, sugar, flavouring, gas/something that makes the bubbles, air (at the top of the bottle) Can you see any gas in the liquid? Probably not...