Earth Science
Chemistry
Physics
Astronomy
Biology
100

The layer of gases that surrounds the Earth.

Atmosphere

100

The smallest unit of an element that retains the properties of that element. 

Atom

100

The measure of the amount of matter in an object.

Mass

100

The time it takes for Earth to complete one rotation on its axis. 

24 hours

100

The basic unit of life in all living organisms.

Cells

200

A large, naturally occurring community of flora and fauna occupying a major habitat, such as a forest or tundra.

Biome

200

A substance made of two or more elements chemically combined in a fixed ratio.

Compound

200

The unit of force named after a famous scientist.

Newton

200

The natural satellite that orbits the Earth.

Moon

200

The organelle known as the powerhouse of the cell.

Mitochondria

300

The process by which water vapor turns into liquid water, often forming clouds.

Condensation

300

The table that organizes all known elements by increasing atomic number.

Periodic Table

300

The rate of change of velocity per unit of time, often discussed in terms of increasing or decreasing speed.

Acceleration

300

The force that keeps planets in orbit around the Sun.

Gravity

300

The process by which plants use sunlight to make glucose from carbon dioxide and oxygen.

Photosynthesis

400

The long-term average weather (temperature and precipitation) in an area.

Climate

400

The negatively charged particles that orbit the nucleus of an atom.

Electrons

400

The physical law stating that for every action there is an equal and opposite reaction.

Newton's Third Law of Motion

400

The phase of the Moon when it is completely illuminated as seen from Earth.

Full Moon

400

The molecules that carry genetic instructions in living things.

DNA

500

The continuous movement of carbon atoms between the Earth's atmosphere, oceans, living organisms, and soil  

Carbon Cycle

500

A change in which one or more substances are converted into different substances, with distinct properties.

Chemical Reaction

500

The principle that states energy cannot be created or destroyed, only transformed or transferred.

Law of Conservation of Energy

500

The star at the center of our solar system.

Sun

500

The part of the cell cycle where the cell divides into two daughter cells.

Mitosis

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