17 terms

# Solar system/Earth and Sun

Earth and sun
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Rotate/Rotation
The act of spinning
Axis
A real or imaginary line that a an object spins around.
Apparent/appear
Apparent motion is the way something appears, or seems, to move. Example is that the sun appears to rise in the east and set in the west. Apparent motion is not real motion.
Revolve/revolution
When one object travels around another. An example is the earth revolves around the sun.
Orbit
A path a reviving object takes. Earths orbit is shaped like an ellipse which is a flattened circle. The Earth's orbit around the sun takes 365 1/4 days or one year.
Tilt
Earth's axis is not straight up and down. Tilted at an angle of 23.5 degrees. The tilt causes the causes sunlight to hit Earth at different angles. Each hemisphere (half) of the Earth gets more or less sunlight. The season result from both the tilted axis and the Earths revolution around the Sun.
Hemisphere
Half of the Earth
Ellipse
A flattened circle. Earth's orbit is shaped like an ellipse.
Solar system
The sun and all the objects in orbit around it. The Sun is at the center.
Satellite
Any object that moves around another, larger body.
Planets
Large objects in space that are satellites of the Sun. There are 8 planets
Gravitational force
The mutual attraction, or pull, between particles of matter. The size of the force depends on the mass and distance. When talking about the Sun moon or planets we call it gravity.
Gravity
The pulling of force between two objects.
Inertia
The tendency of a moving object to keep it's state of motion.
Explain how the pull of gravity and the force of inertia keep planets in there orbit.
It is partly gravitational force- the mutaual aatraction, or pull between the particles of matter.
Each orbit is a balance between gravity and inertia. The planets are really moving in straight line. Gravity causes those lines to curve in, toward the Sun.
What causes day and night?
The Earth moves around the Sun and is also spins. As the Earth orbits the Sun. The Earths spins on its axis. Every day the Earth completes one rotation. One rotation takes 24 hours.
What causes the seasons?
Earth revoves as it rotates around the Sun. The Earths axis is on an angle. The seasons result from Earth's tilted axis and it's revolution around the Sun.