Earthquakes, Volcanoes, and Tsunamis: Projects and Principles for Beginning Geologists
and consists of a skin a meaty part and a core or pit The core of the earth is solid metal iron and nick el surrounded by hot liquid metals The meat of the earth the mantle is a hot somewhat soupy mass of melted rock called magma The skin of the planet is its crust the hard surface of the earth on which we live Crust Mantle Liquid core Solid core 1 250 km 775 mi 2 200 km 2 900 km 1 364 mi 1798 mi The crust is not equally thick all around the earth It is as deep as 40 kilometers 25 miles under the surface of the continents and as thin as 5 kilometers 3 miles under the ocean
Until recently the crust was assumed to be solid rock but discoveries have shown instead that it is cracked into separate sections called tectonic plates Some of them are so large that they determine the boundaries of entire continents or oceans one of the plates supports all of the United States and the whole Pacific Ocean sits on another Other sections are smaller supporting only part of a continent or a small group of islands like the plate under the Car
O AP The Cracked Egg In this experiment you will use a boiled egg to simu late the behavior of the tectonic plates on the earth's surface You'll Need adult helper cooking pot water egg spoon clock or timer 1 Put enough cold water in a pot to cover an egg With the help of a parent or other adult bring the water to a boil 2 Lower an egg into the boiling water with a
Turn the heat down to a low boil and cook the egg for about 7 to 9 minutes 3 Take the egg out of the water and cool it under cold water The egg should be medium cooked not hard 4 Strike the boiled egg gently against a hard sur face like the top of a kitchen table and break the eggshell into a number of pieces some large and some small They will be the tectonic plates of your earth 5 If you now squeeze the egg gently between two fingers the plates will move Some will bump against adjoining plates others will slide along them and some will move away from each other A plate may even slide under an adjoining plate NoTE Since the consistency of a boiled egg varies
