Layers of the Earth • Categorized by composition and physical properties • 3 layers • Crust • Mantle • Core
The CRust • Thinnest layer (5-100 km thick) • Layer we live on • 2 types of crust: • Continental- made up of a material similar to granite, less dense • Oceanic- made up of a material similar to basalt, more dense
The Mantle • Thick compared to the crust (2,900 km) • Middle layer between the crust and the core • Contains most of the Earth’s mass (67%) • Made up of a material similar to the mineral olivine (lots of iron and magnesium)
The Core • Thought to be made of iron with some nickel, sulfur, and oxygen • From the bottom of the mantle to the center of the Earth • 6,856 km in diameter
Physical Layers of the Earth • 5 physical layers • Lithosphere • Asthenosphere • Mesosphere • Outer core • Inner core
Lithosphere • Means “rock sphere” • Outermost, rigid layer of the Earth • Made of the crust and rigid upper part of the mantle • Makes up tectonic plates (pieces of the lithosphere)
Asthenosphere • Means “weak sphere” • Soft layer of the mantle on which pieces of the lithosphere move • Made of solid rock that flows very slowly at the same rate your fingernails grow
Mesosphere • Means “middle sphere” • Lower part of the mantle from the bottom of the asthenosphere to the Earth’s core
Outer and Inner core • Outer core is a liquid layer • Inner core is the solid, dense center of our planet
Density Let’s test the density of some objects
Density • Density is how compact something is or how much stuff you can fit into a certain space • Things sink or float depending on density • If an object is less dense than water it will float. If an object is more dense than water it will sink.
Density Which is more dense? The container on the left or the container on the right?
Density • Seismic waves from earthquakes can be used to determine the density and thickness of the inside of the Earth • Seismic waves will travel at different speeds depending on the density and strength of material seismic waves pass through. For example, a seismic wave will travel faster through solid rock than through a liquid • Seismologists measure the difference in arrival times of seismic waves to calculate the density and thickness of each physical layer of the Earth
Convection Currents • A convection current is a current resulting from uneven heating of a liquid or gas • Examples: • Heating up soup • Air conditioning or heater in your car • Radiator • Convection ovens
Convection Currents • Convection current demo • Tea bag rocket (1:15) https://www.youtube.com/watch?v=GkkrXxJ4db8&feature=fvwrel • Hot chocolate convection current (4:17) https://www.youtube.com/watch?v=PdWYBAOqHrk&feature=related