Core Unit: Earthquakes and Volcanoes

1. Consider earthquakes and volcanoes as direct evidence of crustal movement.
2. Recognize that forces within the Earth can produce folds and faults.
3. Use models to explain how the forces of compression, tension, and shearing contribute to the production of earthquakes.
4. Compare the forces involved in mountain building to those involved in earthquakes.
5. Examine some indirect evidence of crustal movement.
6. Use models to illustrate the theory of plate tectonics.
7. Relate plate tectonic theory to continental drift theory.

1. Discuss, describe, and write about their ideas about earthquakes and volcanoes using their own language.
2. Construct concept webs, diagrams, and models to show their understanding.
3. Compose divergent questions about earthquakes and volcanoes and discuss possible responses to those questions.
4. Rephrase or outline what they have heard and read about earthquakes and volcanoes.

1. Appreciate the use of models, computer simulations, and indirect evidence in an area not amenable to direct experimentation.
2. Focus attention on their own knowledge and gaps in knowledge in this area.
3. Identify gaps in scientist's understanding of these phenomena.

Divide the class into two groups. In the library, ask one group to research ancient means of earthquake detection, while the second group researches modern techniques. Develop visual charts showing examples of modern and ancient methods. Compare the methods.

As in any group situation, encourage students to work cooperatively during the tasks. Assign people in each group to be responsible for manipulating equipment, observing, recording, and reporting. Ask students choose different roles during subsequent activities.

Emphasize that each of the objects they have acts as a model to help understand continental drift. Ask the groups to create analogies that show how each object can represent the Earth.

The hard boiled egg has a thin outer shell. This is analogous to the Earth's crust. The egg white represents the mantle, and the yolk the core. By cracking the shell, students might convey the idea that the crust can be thought of as consisting of sections, rather than continuous, undisturbed matter.

The soccer ball can reinforce that concept about the Earth's crust. The sections of the ball are all joined together. These are analogous to the plates on the crust.

The globe provides a reference for considering the other objects. If the globe has relief contours on it, those might indicate where regions of the plates meet, similar to the boundaries between two connected patches on the soccer ball.

Finally, the shapes of the continents can reinforce the idea of continental drift. Have students arrange the continents on a surface, using the globe to place the shapes in their relative positions. Ask them to try to move the continents together, as if they were moving the pieces in a large jigsaw puzzle until they find the best fit. Once they have the best fit, have them slowly return the continents back to their original position, noting the direction that each one moves. According to the theory of continental drift, forces within the Earth cause the continents to move in this way, .

Alternatively, tape a mirror to the surface of a table or desk. Shine a beam of light on the mirror so that it reflects onto a wall.

In either case, shake the table on which the model is supported and observe the effects on the straw or on the reflected light, respectively.

Repeat the tests, placing different kinds of forces on both ends of the stack. Try pulling both ends apart, pushing both ends together, or twisting both ends in opposite directions. In each case, observe and record the pattern produced. Examine diagrams of folding, bending, and rifting in rock formations. Try to simulate those formations using the layered modelling clay.

Any other objects that can be pressed into distinct layers can be used. Carpet samples, towels, or even a layered chocolate bar would work. Slow, gradual pressure results in folding. Rapid changes in pressure causes cracking.

Look as well for evidence of earthquakes. See if there might be ways that those patterns could be scrutinized closely to make sure they were not caused by erosion. Is there any evidence of plate tectonics elsewhere in our Solar System?

Add a few drops of food colouring, drop by drop. Add them just below the surface of the water, near the centre of the pan. Avoid stirring, in order that the mixing is done as much by convection currents as possible. Observe the motion of the food colouring as convection currents develop.

Use this activity to illustrate movement within the Earth caused by convection.

Another illustration of convection is the type of decorative table lamp that was quite popular in the late 1970s. These lamps contained two different kinds of liquids in them. One formed thick globs which moved up when heated by the bulb at the bottom of the lamp. The globs would hover in the coloured liquid they were in, forming some interesting patterns. As the globs cooled down, they would begin to fall back to the bottom of the lamp.

Remember, the school resource centre is a source of current information.

Develop an activity to investigate this idea further. Research accounts of strange animal behaviour prior to earthquakes. Try to develop (and test, if possible) a hypothesis which might account for the strange animal behaviour.

Alternatively, investigate the claims about a correlation between missing pet announcements in the classified ads and the onset of a major earthquake. Obtain back issues of newspapers from an area which was struck by an earthquake, such as San Francisco on October 17, 1989. Get several copies of newspapers from San Francisco a few months before the earthquake, the few days in succession leading up to the earthquake, and several months after the earthquake. Local or regional libraries may be able to obtain this information through inter-library loan.

Collect all missing pet information from the classified ads and analyze the information to see if students find any relationship between the number of pet announcements and the onset of an earthquake. Repeat using other newspapers either from the same area, or from some other area where a different earthquake disaster took place.

Interviews could be conducted with people who spend a great deal of time with animals, to ask them if they can substantiate any of the claims. The class could also correspond with the scientists who have made the claims about animal behaviour, so that the students could find out how the research was conducted. (In order to duplicate the research, this would be very useful information.)

Relate this activity to pet behaviour before and during a thunderstorm. This helps to put the activity within some perspective familiar to students.

Students should be involved in writing to obtain back issues of these newspapers. (Alternatively, they could search for this information on-line, or find out how it could be borrowed through an interlibrary loan system.) During the activity, take advantage of the opportunity to investigate newspapers for different kinds of information. Local newspapers offer a fascinating glimpse of culture and lifestyles.

The world rests between the divine pillars of Faith, Hope, and Charity. When the deeds of humans weakens any of the pillars, the Earth shakes. (Romania)

The Earth is held up by four elephants standing on the back of a turtle. The turtle stands on a cobra. If any of these animals moves, the Earth trembles and shakes. (India)

The devil makes giant rips in the Earth. He and his friends use the cracks when they want to come up and stir up some trouble on Earth. (Mexico)

The Earth rests on a sled driven by the god Tuli. The dogs who pull the sled have fleas. When the dogs stop to scratch, the Earth shakes. (Siberia)

Mother Earth has a child within her womb called the god Ru. When he kicks and stretches inside the womb, he causes earthquakes. (New Zealand)

The Earth is a living creature, much like humans. Sometimes the Earth gets sick, with fever and chills. When that happens we can feel it shaking. (Mozambique)

Powerful winds are trapped and held in caverns in the Earth. They struggle to escape. Earthquakes are the result of their struggle. (Greece)

In areas with a high risk of danger from earthquakes, what design engineering considerations could be used to make a building earthquake resistant? What can a person do to reduce the risk of being injured if an earthquake is taking place? What do emergency response teams do to prepare for disasters in areas where there is a high risk of an earthquake? Compare the potential danger of earthquakes and safety precautions used along Canada's west coast and in California. What precautions can be taken to reduce potential damage from tidal waves?

Ask students to generate other questions. Add those questions on a large classroom chart as the students progress in their research.