Plate Tectonics
This single, massive supercontinent eventually broke apart due to continental drift.
What is Pangea?
The type of plate boundary where plates move apart, forming mid-ocean ridges and rift valleys.
What is a divergent boundary?
The prevailing model explaining how the universe expanded from an extremely dense and hot initial state.
What is the Big Bang Theory?
These surface features reveal the bombardment history and frequency of collisions in our solar system.
What are impact craters?
These microscopic organisms dramatically changed Earth's early atmosphere by producing oxygen.
What are cyanobacteria?
This rigid, brittle outer layer of the Earth is made up of the crust and the uppermost mantle.
What is the lithosphere?
The type of plate boundary where plates collide, forming mountains, trenches, and volcanic arcs.
What is a convergent boundary?
The approximate age of both the Earth and our solar system.
What is 4.6 billion years?
This method uses the decay of radioactive isotopes to determine the exact age of rocks and fossils.
What is radiometric dating?
Cyanobacteria produce oxygen through this process.
What is photosynthesis?
This hot, semi-fluid part of the mantle lies just below the lithosphere and allows tectonic plates to move.
What is the asthenosphere?
The type of plate boundary where plates slide horizontally past one another, triggering earthquakes.
What is a transform boundary?
These pristine, rocky remnants from space help scientists accurately date our solar system.
What are meteorites?
The time it takes for exactly half of a radioactive isotope in a sample to decay into a stable daughter isotope.
What is half-life?
The mechanical weathering process where water gets into rock cracks, freezes, and expands.
What is ice wedging?
He proposed continental drift but was rejected because he could not explain how the continents moved.
Who is Alfred Wegener?
This process occurs at convergent boundaries when a denser oceanic plate slides beneath a lighter continental plate.
What is subduction?
Our atmosphere is made primarily of these two gases.
What is oxygen and nitrogen?
Earth has far fewer craters than the Moon because of this geological process.
What are plate tectonics, volcanoes or erosion? List at least one.
The mechanical breakdown of rocks caused by the scraping and grinding of other rocks.
What is abrasion?
This property causes materials to sink to Earth's center, while other materials rise. It also causes a penny to sink through corn syrup.
What is density?
This internal force is primarily responsible for moving Earth's tectonic plates.
What is convection currents?
The approximate age of the universe.
What is 13.8 billion years?
Based on a 700 million-year half-life, this is the age of a rock containing exactly 50% Uranium-235.
What is 700 million years?
A type of chemical weathering that occurs when oxygen reacts with iron in rocks, causing them to rust.
What is oxidation?