Earth and Space Flashcards
axis
The imaginary line around which a planet rotates.
The Earth rotates on its axis once every 24 hours causing day and night.
apparent movement
the appearance of movement when actual movement is not happening.
The sun’s apparent movement is caused by the Earth’s rotation on its axis.
rotate / rotation
one complete turn around a fixed point.
The Earth rotates, or spins around its axis.
Sun
A medium sized star at the center of our Solar System.
The Sun is the center of the Solar System and provide heat and light to Earth and the other planets.
revolve / revolution
To travel around another object.
The Earth revolves around the Sun once every 365 days / 1 year. The moon revolves around the Earth once every 28 days / month.
Earth
The third planet from the Sun and the only planet with life.
We live on the planet called Earth. Earth has plants, animals, a breathable atmosphere and liquid water.
Moon
a natural satellite that orbits a planet.
Some planets have many moons, but Earth has only one.
orbit
To travel around another object or the path an object takes as it is traveling around another.
The Earth orbits the sun every 365 days.
The Earth’s orbit takes an elliptical shape.
weight
The force of gravity on an objects mass; its heaviness.
Gravity can change from place to place in the solar system as the amount of gravity changes. Mass never changes.
gravity
the natural force that causes two objects to pull toward each other depending on their mass and their distance.
On earth, gravity pulls the mass of each object enough to keep it there. The moon has less mass than earth, so it has less gravity.
shadow
a dark area that forms when an object blocks light falling on a surface.
When my hand blocks light shining on the wall, I see a shadow in the shape of my hand.
