Journey to the Center of the Earth

Scientists that study the Earth Geologists: Scientists that study the forces that make and shape planet Earth. They study the chemical and physical characteristics of rock. Geologists study the processes that create Earth’s features and search for clues about Earth’s history. Geology is the study of the solid Earth and the processes by which it is shaped and changed.

Scientists that study the Earth Paleontologists: These scientists study the forms of life existing in former geologic periods. The science of Paleontology helps us learn about the history of different species that have inhabited Earth. Information we have regarding dinosaurs, wooly mammoths, trilobites, and other extinct species come from fossil formations found and studied by paleontologists.

Forces that Cause Surface Changes Constructive Forces: Shape the surface by building up mountains and landmasses. (Example Surtsey-2 Miles) Destructive Forces: Slowly wear away mountains and eventually every other feature on the surface. (Example: Weathering)

How do we know about the interior of the Earth? Any ideas???? (Hint it is not because we sent Brendan Frasier down there)

How do we know about the interior of the Earth? We know about the composition of the interior of the Earth because of Seismic Waves. (Earthquake Waves) The speed of these seismic waves and the paths they take reveal how the planet is put together. P (primary) waves can travel through every layer of the earth. In solids, these waves generally travel almost twice as fast as S waves and can travel through any type of material. S (secondary) waves can only travel through solids.

Layers of the Earth There are 4 main layers to the Earth. Crust, Mantle, Outer Core, and Inner Core. As you go towards the center of the Earth the temperature and pressure increases greatly.

The Crust The layer of rock that forms the Earth’s surface. The crust includes rocks, mountains, soil and water. The crust is the smallest layer of the earth. (Apple Example) There are two types of crust oceanic crust (Basalt which is an igneous rock) and continental crust (rocks like Granite which is an igneous rock)

The Crust Cont… The oceanic crust is 5km (3mi) to 10 km (6mi) thick and is composed primarily of basalt, diabase, and gabbro. The average density of the oceanic crust is 3g/cm³. The continental crust is typically from 30 km (20mi) to 50 km(30mi) thick and is composed of sighlty less dense rocks than those of the oceanic crust. he average density of the continental crust is 2.7g/cm³. Earth’s crust occupies less than 1% of the Earth’s volume. The temperature of the crust increases with depth, reaching values typically in the range from about 200°C (392°F) to 400°C (752°F) at the boundary with the underlying mantle.

The Mantle The mantle is a layer of hot soild material The mantle is solid but has liquid like characteristics. (It’s kind of like Silly Putty) The mantle is the largest of the layers of the earth It is mainly composed of silicon, oxygen, iron, and magnesium.

The Mantle Cont… It begins about 6 miles(10 km) below the oceanic crust and about 19 miles (30 km) below the continental crust (see The Crust). It is about 1,800 miles(2,900 km) thick and makes up nearly 80 percent of the Earth's total volume. The function of the mantle is to separate the inner mantle and the outer mantle. The average temperature is 5400 ºF (3000ºC), nevertheless the rock is solid because of the high pressures. The bottom layer is tough liquid rock and probably consists of silicates of iron and magnesium. The temperature in this part is between 2520 ºF (1400ºC) and 5400 º F (3000ºC) and the density is between 3.4g/cm³ and 4.3g/cm³. The upper layer of the outer mantle consists of the same material but is stiffer because of its lower temperature.

The Outer Core The outer core is a layer of molten metal that surrounds the inner core. In spite of enormous pressure the outer core behaves like a thick liquid. Currents in the liquid outer core force the solid inner core to spin at a slightly faster rate than the rest of the planet. These currents in the outer core create the Earth’s magnetic field. This is why you can use a compass and the Earth is protected from some of the harmful rays of the sun. Composed of mostly Iron and Nickel Its outer boundary lies 2,890 km (1,800 mi) beneath the Earth's surface. The temperature of the outer core ranges from 4400 °C in the outer regions to 6100 °C near the inner core

The Inner Core The inner core is a dense ball of solid metal. It is also mainly composed of iron and nickel. Temperature range is probably between 2,000-5,000 degrees Celsius and about 1,216 km (760 mi) in radius. The center of the inner core is thought to be as hot as the surface of the sun.

Plate Tectonics Plate Tectonics is the geological theory that states that pieces of Earth’s crust are in constant, slow motion, drive by convection currents in the Earth’s mantle. No plate can budge without affecting the other plates surrounding it. As the plates move, they collide, pull apart, or grind past each other.

Plate Tectonics Plate movements cause volcanoes to erupt, mountain ranges to be formed, and earthquakes to occur. Plate Tectonics are responsible for the deformation of Pangea. Plate Tectonics Introduction Plate Tectonics Evidence Movement of Earth's Tectonic Plates The Man Behind Plate Tectonics We will be reading more about Plate Tectonics in a few days.