Day 1: (Duration: 60 minutes)
1. Read a book about the Earth’s Layers. I use Planet Earth/Inside Out by Gail Gibbons (1998).
2. Look up a picture of the Earth’s layers (here’s a good URL: http://www.universetoday.com/61200/earths-layers/) or use a poster that shows the Earth’s layers. Introduce or review the different layers of the Earth. Point out the core, mantle, and crust.
3. The Earth’s layers are similar to a hard-boiled egg. If possible, you could give students a hard-boiled egg to investigate in small groups. The yolk would be the core, the white would be the mantle, and the shell would be the crust.
4. Tell the students they will be making a model of the Earth using either clay or model magic.
5. Explain, the very center of the Earth is the inner core. It is made of hot, solid, squeezed-together metal. The inner core of Earth is larger than our moon! We think it is made of nickel and iron.
6. Children will work in pairs now. Give each pair a small (between pea- and walnut-sized) ball of yellow model magic or clay. Ask students to make a sphere. Ask what they know about the inner core as they work. Have them set it aside.
7. Explain that moving out from the center of the Earth is the outer core. It is made of melted metal (nickel and iron) as thick as syrup. The movement makes heat, and the heat gives the Earth its magnetic field.
8. Give each pair a piece of orange model magic or clay. This time, students should pat the clay out (or roll it) to about ¾” thickness. It needs to be big enough to cover the sphere, but not too big. Ask students to gently wrap the sphere in the orange model magic. Excess can be pulled off and saved. Next, children should gently reshape it into a sphere. They should not squeeze it too hard!
*This is usually a good place to pause the lesson and let the inner and outer cores dry. Review the layers of the Earth you’ve made. Put the model on top of a baggie or note card with the owners’ names written on it.
Day 2: (Duration: 60 minutes)
1. Take out the Earth models. Ask children what they’ve added already (inner core and outer core).
2. Use the poster (or online graphic) to show children the mantle. Remind them it is the “white part of the hard-boiled egg.” The Earth’s mantle has 3 parts.
3. Explain to students that the deep mantle is made of very hot melted rock called basalt. It is pressed so hard it seems solid.
4. Give each pair a piece of red model magic or clay. Ask them to share and flatten the model magic to make a pancake about ¾” thick that will cover their Earth’s core. Have students wrap the core in the pancake and gently squeeze the excess off. Ask students to reshape the Earth into a sphere. Review the Earth’s layers again (inner core, outer core, and deep mantle).
5. The next layer of the mantle is the asthenosphere. This is where volcanic lavas are produced. There is slow movement in this layer.
6. Give each pair enough black model magic or clay to flatten to ½” and cover the sphere. Follow the same procedure (pancake, wrap, and reshape).
7. The next layer in the mantle is the lithosphere. It is made up of 12 large plates and many small plates. This layer is cool and rigid. The plates seem to slip and slide over the asthenosphere. Earthquakes start here.
8. Give each pair enough brown model magic to make a thin ¼” layer and follow the same procedures as the other times.
9. Last, the children are going to make one more layer for their Earth- the Earth’s crust. Use the green and blue model magic or clay.
– Explain to students that the top layer of the Earth is called the crust. It is made up soil and rocks. The continental crust (land) can be 4 to 22 miles thick. The oceanic crust (soil and rocks under the oceans) can be up to five miles thick. Think of the crust as the hard-boiled egg’s shell. Compare it to the size of the core and mantle by using the poster or graphic.
10. Students should make the crust by using blue and green model magic. Students can make a
hodgepodge of the colors, and then roll out as thin as possible.
They should wrap it around the sphere to complete the Earth’s layers.
11. Set the earth models somewhere to dry. Give the models a few days to dry, and then cut them in half. Each child can take home ½ of an Earth model!
12. Have students fill in the diagram if there is time.
- model magic (or colored clay): yellow, orange, red, black, brown, green, and blue
- NM Science Strand II: Content of Science: Standard III (Earth and Space Science): Understand the structure of Earth, the solar sy stem, and the universe, the interconnections among them, and the processes and inte ractions of Earth’s systems.
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