1. E a r t h ’ s I n t e r i o r

2. The Science of Geology Geologists- scientists who study the forces that make and shape planet Earth. – They also: study the chemical and physical characteristics of rock. map where different types of rock are found describe landforms Rock- the material that forms Earth’s hard surface. Geology- the study of planet of Earth. It began in the late 1700s.

3. Is Change a Good Thing? Forces beneath the surface are constantly changing Earth’s appearance. The forces that change the Earth’s surface are divided into two groups: 1. Constructive forces- shape the surface by building up mountains and landmasses 2. Destructive forces- slowly wear away mountains and eventually every other feature on the surface.

4. A Journey to the Center of the Earth As you start to travel beneath the surface the rock is cool for about 20 meters. Then the rock starts to get warmer. The deeper you go the greater the pressure. – More pressure because of the weight of the rock above. – Pressure is the force pushing on a surface area.

5. A Journey to the Center of the Earth 3 main layers – Crust – Mantle – Core

6. The Crust Not this crust!

7. The Crust Crust - Earth’s solid and rocky outer layer. – This includes the land surface and the ocean floor. Rocks, mountains, soil and water – The crust ranges from 5-40 km thick. The thinnest of all the layers. – The crust beneath the ocean is called oceanic crust. Consists mostly of basalt. – Continental crust is mainly made up of granite.

8. The Mantle A layer of hot rock. 2,900 km thick Pressure and temperature increase the deeper you go.

9.  Three types of heat transfer:

10.  Radiation › The transfer of energy through empty space. › There is no direct contact between a heat source and an object. › Examples:  Sunlight is radiation that warms Earth’s surface.  The heat you feel around a flame or fire.  Conduction › Heat transfer by direct contact of particles of matter. › Example:  When a spoon heats up in a pot of soup  Heat is transferred from the hot soup and the pot to the particles that make up the spoon.

11.  Convection (How the soup in the pan heats up) › Heat transfer by the movement of heated fluid. › During convection, heated particles of fluid begin to flow, transferring heat energy from one part of the fluid to another › When the liquid gets heated the particles start moving faster and they spread apart. › When the fluid cools the particles move more slowly and settle closer together.

12.  Convection Continued: › Density - the measure of how much mass there is in a volume of substance. › Remember from the last slide that when particles are heated they spread apart so the density decreases.  The warmer substance moves to the top because it is less dense and the cooler sinks to the bottom because it is more dense (particles get closer together). › We have convection currents in the Earth’s mantle.

13. The core is made up of two parts. – OUTER CORE- – OUTER CORE- 2,250 km thick LIQUID LIQUID A layer of molten metal – INNER CORE – INNER CORE-1,200 km thick SOLID SOLID The extreme pressure squeezes the atoms of iron and nickel so much that they cannot spread out and become liquid. EARTH’S MOON The outer and inner core together are just smaller than the EARTH’S MOON

14. Earth’s Magnetic Field Currents in the liquid outer core cause the solid inner core to spin. The inner core spins inside Earth. This movement causes Earth’s magnetic field. – A magnetic field is caused by moving electrical charges. This is what causes the compass needle to point north. It aligns with Earth’s magnetic north pole.

16. Who Went to the Center of the Earth?

17. So How Do We Know What is There? Scientists rely on indirect methods They use seismic waves (similar idea to knocking on a wall to listen for a change in sound if you were looking for a beam to nail a picture to). – A vibration that travels through Earth carrying the energy released during an earthquake. – The speed of the seismic waves and the paths they take reveal how the planet is put together.