1. BILLION

2. Engage/Explore Spin eggs on a demo table to determine which egg is raw and which is cooked. What is a model? What are some models that we have used this year to represent the real world? The egg is like a model of the layers of the Earth. (see layers of the Earth handout on the Elmo)

3. Structure of the Earth The Earth has three main layers: the crust, the mantle, and the core. Label the three layers on the diagram. What layer of the Earth might the eggshell represent?

4. Structure of the Earth The egg shell will represent the thin outer layer of the Earth called the crust. The crust is the layer that we live on. It is made of solid rock and soil. It is about 25 miles thick under the continents and about 5 miles thick beneath the oceans.

5. Structure of the Earth How is the eggshell like the crust of the Earth? It is the thinnest layer, it is on the outside, it is rigid or hard, etc. How is it different than the crust of the Earth? It is not made of rock, it is much smaller than the real thing, it is white, etc. What layer of the Earth might the egg white represent? The mantle

6. Structure of the Earth The mantle is much thicker than the crust. The mantle is mostly solid, but it is flexible, kind of like the white of the egg. (Push on the white part gently to see that it moves.) The temperatures below the crust get very hot. They are so hot that some of the lower crust and mantle are made of melted rock that moves very slowly and flows. This hot molten rock is called magma.

7. Structure of the Earth What layer of the Earth might the yolk represent? The core The core of the Earth is mainly made of iron and nickel. The Earths magnetic field is likely due to the interactions of these magnetic metals. What would happen if I press down on the shell of the egg with my thumb? Do the cracks divide the eggshell into pieces? Yes.

8. Structure of the Earth The Earths crust is cracked into pieces just like the pieces of this egg shell. These pieces are like puzzle pieces that sit or float on the hot molten rock below. Scientists call these puzzle pieces plates. The cracks or weak places in the Earths crust are called faults.

9. Structure of the Earth The Earth, both inside and out, is constantly changing. Forces of nature, such as heat, pressure, wind, water, etc., are responsible for many of these changes. Label your diagram and fill in the blanks.

10. Models for the Earths Interior Using four different models of the earth, you will identify the layers and evaluate the strengths and weaknesses of the models.

11. Models for the Earths Interior Materials: 1 raw egg 1 hard boiled egg 1 clear drinking straw for the hard boiled egg, cut into 3 short pieces 1 plastic knife 1 mini snack size milky way bar for each student 1 apple 1 kiwi Paper towels

12. Models for the Earths Interior Procedure: 1. Crack a raw egg into a glass bowl and place it under the Elmo. Student Quickwrite: How is this egg like the earth? How is it different? 2. What is the purpose of a model? 3. Introduce the 4 models: hard-boiled egg, milky way, kiwi, and apple. For each model, identify the parts that correspond to the earths layers and write how the model demonstrates characteristics of these parts.

13. Models for the Earths Interior Hard-boiled egg: Make cracks in the shell of the egg by rolling it in your hands or on the desk. Trace the lines of the cracks on the surface with the marker. This can be compared to the crust of the earth with plates. How can we find out what is inside the egg without opening it? Use the straws to take core samples of the egg. What information can scientists find out from taking core samples of the earth?

14. Models for the Earths Interior Cut the egg in half and identify the layers/compare the representation of the layers to what we know about earths layers (solid, liquid, etc.) Apple Cut in half, identify parts.

15. Models for the Earths Interior Milky Way: Unwrap the candy bar and use your fingernails to carefully make a few cracks across the top. What does this model? (Earths crust, also called the lithosphere. Holding the candy bar on either end, slowly pull apart the candy until the caramel is visible. What does this represent? (magma, mantle) Push the bar back together. The chocolate may crumble or form mountains. What does this represent?

16. Models for the Earths Interior Experiment with pushing and pulling the bar to get an idea of what happens with the plates. Cut the candy bar in half to examine the layers. What layers are represented? Make sure your chart is complete.