Lesson Four: The Earth, Layers of Earth
Students will use papier-mâché to create models of Earth, build sealed models of Earth's surface and atmosphere, simulate the movement of tectonic plates using paper ones, and more.
- Grades: 6–8
- Unit Plan:
In these four hands-on activities, students will learn about the layers of Earth, the atmosphere, and the movement of tectonic plates in Earth's crust. Things are about to get messy!
- understand that Earth is a planet constantly being formed and transformed
- explore basic principles of geology
- develop rational and creative thinking skills
- work co-operatively in groups
- Following directions
- Hard-boiled eggs, one for demonstration, plus one egg per group of three or four students for the optional activity
- Sharp knife (Safety Note: Only the teacher should handle the knife during the activity.)
- Shower curtain, tarp, or newspaper to protect surface
- Sheets of newspaper, at least ten pages per group of three or four students
- Papier-mâché paste
- Uninflated balloons, one per group of three or four students
- Large scissors
- Thin card paper, at least one sheet per group
- Felt-tip pens
- Blue, green, and brown acrylic paint
- Optional: Wire or string for hanging Earth models
- A globe or maps of the world
- Deep-sided containers, one for each group of three or four students
- Access to water and containers to transport it
- Craft wire
- Plastic wrap
- Observation notebooks or reproducibles
- Paper plates, one per student
- Construction paper, 1/4 of a sheet per student
Set Up and Prepare
- Hard-boil at least one egg. You will need one egg for a class demonstration. If you decide to do the optional activity, you will need additional eggs for each group of three to four students.
- Cut the construction paper sheets lengthwise into fourths, producing four long strips of paper per sheet. You will need one strip for each student.
Step 1: Use a hard-boiled egg to demonstrate the structure of Earth. Tell students that Earth has layers inside it, just like an egg does.
Step 2: Carefully tap along the equator of the egg to crack the shell. Explain that the eggshell is like the rocky crust of Earth.
Step 3: Use a sharp knife to slice the egg in half along the crack. Show the inside of the egg to the students.
Step 4: Explain that the egg white is like the solid rock mantle of Earth. The egg yolk is like the molten outer core and the solid inner core.
Optional: Divide students into groups of three or four and give each group a hard-boiled egg to explore.
Step 1: Choose a papier-mâché station and cover the designated table or floor with a shower curtain, tarp, or newspaper.
Step 2: Explain to students that they will be making papier-mâché models of the structure of Earth. Break students into groups of three or four and have them tear sheets of newspaper into 2-inch strips.
Step 3: While students are tearing the newspaper, mix the papier-mâché paste.
Step 4: Give each group a balloon. Have them inflate the balloon and tie it off.
Step 5: Invite groups over to the papier-mâché station one at a time. Help each group cover their inflated balloon with layers of papier-mâché.
Step 6: When the papier-mâché models are strong and dry, show students how to carefully cut away a cross-section.
Step 7: Hand out the sheets of thin card and have students cut out circles that will fit into the cross-sections of their models. They should fold the circles into the cross-section, then remove the circles again.
Step 8: Demonstrate how to draw the layers inside Earth with felt-tip pens, then fit the inside view into the cut-away section and attach with tape.
Step 9: Have students paint the outside of Earth.
Step 10: Suspend the models from the ceiling or display them with appropriate labels.
Step 1: Have students look at a globe or maps and estimate the proportion of Earth's surface that is covered with water. They should conclude that the surface of Earth is mostly water. In fact, about 71 percent of Earth's surface is covered with water. Encourage students to use this knowledge when constructing their own working model of Earth's surface and its atmosphere.
Step 2: Have each group of three or four students arrange soil, rocks, and water in a deep-sided container.
Step 3: Help the groups make frames for the top of the containers out of wire. They should cover the wire frame with plastic wrap. This lid will represent Earth's sealed atmosphere.
Step 4: Have each group record their observations over the next few weeks. They should observe and comment on any changes to their model Earth using the appropriate terms: evaporation, condensation, plant growth, and so on.
Step 1: Explain that the crust of Earth is made up of large plates of rock that might be covered by sand, soil, or water. These rock plates are always moving. They move about 2 to 15 cm every year. That's about the same amount as a fingernail grows in the same amount of time.
Step 2: Have each student cut a paper plate in half.
Step 3: Have students tape the edge of a rectangle of paper onto one half of the plate. Then have them attach the loose end of the paper onto the other half of the plate so the paper stretches across both halves.
Step 3: Have students experiment by sliding one side of the plate under the other. The paper rectangle will rise. Explain that over millions of years, mountains form in the same way. Earthquakes occur when the creeping plates get stuck. Pressure builds until the plates suddenly slip, releasing earthquake energy.
Adapted from "The Earth," Senior Topics. Published by Ashton Scholastic in Australia.