What shape is the Earths orbit The Earths

What shape is the Earth’s orbit? • The Earth’s orbit around the sun is shaped like an ellipse. • A circle (for the most part). • Ex: If the orbit is a circle, what causes the seasons?

How does sunlight strike the Earth’s surface? • Near the equator, sunlight strikes Earth’s surface more directly and is less spread out than near the poles. • Please draw this picture in your notes.

What causes the seasons? • Earth has seasons because Earth is tilted as it revolves around the sun – not because it is closer to or farther from the sun! How much is it tilted?

What is equinox and solstice? • Equinox = neither end of Earth’s axis is tilted toward the sun. • Solstice = North or south end is tilted toward the sun.

What is gravity? • Gravity is a force that attracts all objects toward each other.

What determines the strength of gravity? • The strength of the force of gravity between two objects depends on two factors: the masses of the objects and the distance between them.

What is the law of gravitation? • Every object in the universe attracts every other object.

If gravity is constantly pulling, what keeps the moon in orbit? • Newton concluded that two factors–gravity and inertia–combine to keep the moon in orbit around Earth. • Dance, Dance (Gravity and Inertia)

What is inertia? • The tendency of an object to resist a change in motion.