Cross Section of the Earth: Egg Modeling

Materials

Boiled egg (in its shell); Plastic knife; Small cup of water; Pushpin; Paper plate

Activity

1. Look at the boiled egg and imagine that it represents the Earth. Look at the shell surrounding the egg. What part of the Earth do you think this represents?
2. Dip the blade of the plastic knife in water and carefully cut the egg in half lengthwise. Do not peel the egg; cut through the shell as well.
3. Examine the inside of one half of the egg. Set the other half aside for the extension activity.
4. Use the pushpin to make a small indention in the center of the yolk in the interior of the egg.

Follow-Up Questions

1. What does the shell of the egg represent? What does the egg white represent? What is represented by the majority of the egg yolk? What does the pinprick inside the yolk represent?
2. How is the egg model similar to the real Earth? Which elements in this model are wrong?

Answers

1. The eggshell represents the Earth's crust, the egg white is the mantle, the yolk represents the core, and the pinprick inside the yolk represents the inner core.
2. Answers will vary and could include the fact that the egg and the Earth have similar layers, but the egg and the Earth are not exactly the same shape.

Extension

Gently crack the external shell of the unused egg half so that it has several broken segments. What do you think this now represents? Note that these segments can push against one another. What does that represent?