Our Home: Earth, A Unique Life Sustaining Planet

Vocabulary flashcards reviewing key concepts about Earth's life-sustaining features, internal structure, and its place within the Solar System.

Distance from the Sun

A location factor that keeps Earth neither too hot nor too cold, maintaining a suitable temperature essential for the evolution and existence of life.

Circulating Life Elements

Carbon, nitrogen, hydrogen, and oxygen, which continually circulate between the atmosphere and the Earth to ensure life continues.

Structure of Earth

The internal composition of Earth made up of three main layers: Core, Mantle, and Crust.

Crust

The thin, outermost layer of Earth made of light rocks that holds various water bodies, landforms, and life forms.

Air

A mixture of several gases containing oxygen, which land organisms breathe directly from the surroundings and aquatic organisms take from dissolved gas in water.

Soil

An essential natural resource that supports plant growth by holding roots firmly and supplying water and nutrients, making agriculture possible.

Solar System

The Sun and its family of objects, consisting of eight planets, their satellites (or Moons), and millions of smaller celestial objects like asteroids, comets, and meteoroids.

Orbits

Fixed, closed elliptical paths in which planets and other celestial objects revolve around the Sun.

Planets

Large celestial objects that revolve around the Sun in closed elliptical paths, having no light of their own and shining by reflecting sunlight.

Eight Planets in Order

The planets ordered by increasing distance from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Naked-Eye Planets

The five planets easily seen without a telescope that were known to ancient astronomers: Mercury, Venus, Mars, Jupiter, and Saturn.

Telescopic Planets

The two planets located very far from the Sun that were discovered with the help of a telescope: Uranus and Neptune.

Inner Planets

The first four planets closest to the Sun (Mercury, Venus, Earth, and Mars), which are made of rock and metal.