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Sun
the spinning motion of a planet on its axis
Rotation
the amount of matter in an object
mass
What is a force?
a push or pull exerted on an object
What is an AU?
Astronomical Unit
The study of the moon, stars, and other objects in space
Astronomy
What is relative size?
How the size of one object compares to another
the force of gravity on an object
weight
What is gravity?
The attractive force between objects
What is an axis?
An imaginary line that passes through Earth’s center and the North and South poles, about which Earth rotates
the movement of an object around another object
Revolution
What is an orbit?
the path of an object as it revolves around another object in space
What is a scale model?
A smaller or larger representation of an object that keeps the same proportions as the real object
the two days of the year on which the sun reaches its greatest distance north or south of the equator
solstice
What shape is Earth's orbit?
An ellipse
the two days of the year on which neither hemisphere is tilted toward or away from the sun
equinox
The Law of Universal Gravitation states
the scientific law that states that every object in the universe attracts every other object
What two factors keep Earth in orbit
Inertia & Gravity
What two ways does Earth move throughout space
rotation and revolution
Earth has seasons because its axis is tilted as it revolves around the sun
What is a calendar?
A system organizing time that defines the beginning, length, and divisions of a year
The strength of gravity depends on two factors...
1. mass
2. distance
Earth's rotation causes day and night, while its revolution around the Sun determines the length of a year.
What is Newton's First Law of Motion
the scientific law that states that an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted on by a force
What are some challenges when creating a scale model?
Limited space
Keeping proportions accurate
Time and movement