What is an earthquake demo:
- Ask the students what they know about earthquakes. You can list their responses on the board.
- Tell students that you are going to demonstrate what causes an earthquake. Set the 2 piece of Plexiglas on the table side by side. Describe how the gap between the pieces represent a “fault” a crack on the Earth’s surface that is susceptible to suddenly giving way and moving. Don’t talk about tectonic plates yet since the students will soon discover their existence on their own! Simply refer to the pieces of Plexiglas as pieces of land with a fault in between.
- Lay a 6 inch piece of scotch tape along the fault line. Describe how the tape represents the rocks and soil along the fault that help hold the pieces together. Make the junction secure but don’t work too hard at taping the pieces together or you will have to push very hard to get the fault to slip.
- Optional: decorate the surfaces with Monopoly houses and pieces.
- Slowly and steadily push one piece of Plexiglas away from you while pulling the other piece towards you. Eventually the tape will give way and suddenly break free. Monopoly pieces may scatter.
- Discuss with your students what they observed, paying particular attention to the energy that is stored and suddenly released.
- Pass out the handouts and go over their assignment.
- Allow each student to pick one slip of paper with a time frame on it.
- Give students 35-45 minutes to complete their research on the website.
- Remind students that they should mark the location of each earthquake on their list on the map for homework if they didn’t finish it in class.
Plotting earthquake locations:
- Ask students to get out their handouts from the previous day.
- Explain the procedure for the day. Each student will share details about one of the earthquakes they researched (preferably the one they used as an answer to question #4 on their handout). Then they will be given some color dots to plot the location of each of their earthquakes on the large map. Different colors will represent earthquakes of different magnitudes (red is not used here since it will represent volcanic activity in the Plate Patterns activity).
|5.9 or lower
- One by one, have students come up to the front of the room to present their earthquake. They should describe the date it occurred, the magnitude, the location, and the 3 facts they learned about it.
- After a student finishes, give him/her sticky dots to plot their earthquakes on the map. While they plot their information, another student can come up and describe their research. Regulate the flow so that no more than 2-3 students are plotting their data on the map at one time.
- When all students have gone and all the data is plotted on the map, discuss any patterns you see on the map as a class. The goal here is really to have the students relate what they learned about the causes of earthquakes from the demonstration to what they are seeing on the map. The faults are the lines of earthquakes. The large blank areas are like the pieces of Plexiglas and are called tectonic plates. Some questions to consider include:
- Where are we? How many major earthquakes have occurred near us?
- Are the earthquakes evenly distributed across the map?
- What are the most active earthquake areas in the world?
- What do the clusters of earthquakes look like? Do they cluster in patches or in lines?
- Look at the magnitude information. Where do the biggest earthquakes take place?
- Think back to the demonstration at the beginning of this lesson. Remember how earthquakes are caused when energy is suddenly released along a fault. Where are the big faults on the planet (think of it as an abstract dot-to-dot drawing)?
- The Plexiglas represented large pieces of land bordered by faults. Geologists call these large pieces of land tectonic plates. Where are the tectonic plates? How can we use the earthquake data to find the edges of the plates?
- Do ALL earthquakes happen at the edges of plates? (No.) What are some of the exceptions that don’t seem to fit the general pattern.
- Optional: Have students copy the patterns you discover onto their personal maps on the handout – defining the plate boundaries and faults in between.