Planet Earth Lecture Notes

A collection of vocabulary flashcards covering Earth's internal structure, plate tectonics, fossil evidence, and energy resources based on the lecture notes.

Inner core

A dense, white hot, solid iron ball about $2\,400\,km$ in diameter located at the deepest layer of the Earth.

Outer core

The molten layer of the Earth's interior composed of liquid metal that is nearly as hot as the surface of the sun.

Mantle

A layer about $2\,900\,km$ thick made of rock that is so hot it flows under pressure like road tar.

Crust

The outermost layer of the Earth, ranging from $8\,km$ thick beneath the oceans to an average of $40\,km$ thick beneath the continents.

Basalt

A dense rock that makes up the seafloor and presses deeper into the mantle, producing basins that can fill with water.

Seismic waves

Waves from earthquakes that scientists use to map the interior of the Earth by observing how they are bent, reflected, or delayed.

Lithosphere

The rigid outermost shell of the planet, approximately $100\,km$ ($60\,miles$) thick, which is made up of the crust and upper mantle.

Asthenosphere

A partially molten layer of the Earth located directly beneath the lithosphere.

Plates

Blocks of the Earth's crust broken by currents within the mantle that move to build mountains or form new seafloor.

Convergent plate boundaries

Boundaries that form subduction zones, often resulting in earthquakes, volcanic activity, and mountain-building.

Divergent plate boundaries

Boundaries where plates move apart, often resulting in the formation of oceanic trenches.

Plate motion (Tectonic shift)

The movement of plates typically ranging from $0$ to $10\,cm$ annually, caused by convection currents from radioactive processes in the planet's interior.

Pangaea

The single supercontinent that existed $250$ million years ago before tectonic shift separated the landmasses.

Panthalassa

The single, vast ocean that surrounded the supercontinent Pangaea $250$ million years ago.

Mesosaurus

A freshwater reptile whose fossils have been found in both Brazil and western Africa, providing evidence that the continents were once joined.

Lystrosaurus

A land reptile whose fossil remains have been discovered in Africa, India, and Antarctica.

Cynognathus

A Triassic land reptile approximately $3\,m$ long whose fossils serve as evidence for plate tectonics.

Glossopteris

A type of fern whose fossils are found in all southern continents, showing they were once part of a single landmass.

Non-renewable resources

Energy resources that will eventually run out if continually used, such as coal, crude oil, and natural gas.

Fossil fuels

Energy sources formed many millions of years ago by the remains of trees (coal) and sea creatures (petroleum and natural gas).

Hwange Power station

A thermal power station in Zimbabwe that burns coal to produce electricity.

Generator

A large magnetic coil in a power plant that is turned by a turbine to generate electricity.

Carbon dioxide

A polluting greenhouse gas produced by burning fossil fuels that contributes to climate change.

Renewable resources

Energy sources that can be used repeatedly without running out, such as wind, solar, biomass, and geothermal energy.