Lesson Plan #:AELP-EAR002
Submitted by: Janet Donnelly, C.C.Meneley Elementary, Gardnerville, NV
Endorsed by: These lesson plans are the result of the work of the teachers who have attended the Columbia Education Center’s Summer Workshop. CEC is a consortium of teachers from 14 western states dedicated to improving the quality of education in the rural, western, United States, and particularly the quality of math and science Education. CEC uses Big Sky Telegraph as the hub of their telecommunications network that allows the participating teachers to stay in contact with their trainers and peers that they have met at the Workshops.
Date: May 1994
Grade Level(s): 3, 4, 5, 6, 7, 8, 9
Overview: Using a nectarine to represent our planet Earth, this visual demonstration can give the students a clearer understanding of the ratio and proportion of the Earth’s crust, core, and usable land surface. Purpose: A simulation is the best way to approximate an actual experience. When an event is fun and interesting the material is usually retained longer. This lesson provides a concrete example of the limited size of the land surface we share with the Earth’s other inhabitants and a visual representations of the Earth’s inner sections.
Objective: The learner will be able to identify the crust, mantle, and core of the Earth and be able to give an approximate ratio and proportion of usable land surface.
- paring knife
(Nectarines are only available in the summer and fall. If you cannot obtain them, an apple can be a suitable substitute… though the proportions are not as comparable. You can use one nectarine per person, per group of four, etc. I have also given this lesson as a teacher demonstration. This would be advisable with younger students if you are concerned about using knives in the classroom.) Procedure:
Cut the nectarine in half. Explain that the ratio and proportion of this nectarine is similar to the Earth. The skin is approximately the thickness of the Earth’s crust. The flesh of the nectarine is similar to the mantle of the Earth. Mantle is molten rock and material. When there is a break in the Earth’s skin, the mantle can pop up… as in a volcano.
At the center of the nectarine is a large pit and inside the pit is a seed. This can represent the inner and outer core of the Earth. The pit is similar to the outer core made up of liquid nickel and iron. Thus it is very heavy and creates our gravity. The inside (the seed) is made up of solid nickel and iron. The tremendous pressure makes it solid.
Now for the surface… because the ocean covers 3/4 of the land’s surface, cut away half of the half of the half you’re holding. (3/4 is taken away, 1/4 is in your hand.) This represents the total land of the Earth.
Since 1/3 of the land is covered by mountain ranges and is too cold and unsuitable to live upon, cut away another 1/3 of the piece you’re holding.
Yet another 1/3 of the land surface is desert terrain and too hot for us to live upon. Cut away another 1/3 of the piece you’re holding.
The tiny sliver of land that you still have is all the usable land surface that must support all the people and animals alive today! Let’s use this valuable Earth carefully as it’s the only home we have.
Tying It All Together:
This could be an introduction to a unit on our environment, recycling, pollution control, etc.
Students could color in a picture of a cut-away model of the Earth and label each of the parts, such as core, mantle, etc.
The students could cover a globe with post-it notes and then graph it with sections for ocean, mountains, deserts, tropical forests, etc.
The class could follow the lesson with creative journal entries on how it made them feel to realize the tiny size of usable land space on Earth.
Paper mache globes could be made over small balloons. Prick the balloon when the globe is dry, and paint the surface.