The Seasons How are the seasons caused?

True or False? Seasons are a result of the distance from the sun. False! Earth is farthest from the sun during the summer in the Northern Hemisphere. So what does cause the seasons?

Earth’s Axis Is Tilted The tilt is always in the same direction, even as Earth rotates around the sun, so part of the year it points toward the sun, and part of the year it points away from the sun.

Temperature Vary due to Angle of rays Equator – sun’s rays strike surface at a 90° all year, resulting in greater intensity of radiant energy.

Temperatures Vary due to Angle of Rays Farther away from the equator, areas receive less radiant energy. – Since the angle at which the sun’s rays strike Earth is less than 90° so the rays are less direct. – The same amount of radiant energy is spread over a larger area. (Less heat = lower temperatures )

Angle of the Sun

What causes the seasons? The seasons are caused by the tilt of Earth’s axis as Earth travels around the sun.

Earth Revolves Around The Sun

Weather & Seasons The weather changes as the seasons change.

The Axis Tilts in the Same Direction As Earth travels around the sun, the axis always points the same way. When Earth is on one side of the sun, Earth tilts toward the sun. On the other side, Earth tilts away from the sun.

Position of Earth For Each Season When Earth tilts toward the sun, it is summer in the Northern Hemisphere.

Position of Earth For Each Season When Earth tilts away from the sun, it is winter in the Northern Hemisphere.

Position of Earth For Each Season When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere. When it is winter in the Northern Hemisphere, it is summer in the Southern Hemisphere.

Position of Earth For Each Season During the spring and autumn, the tilt does not point toward or away from the sun. Both hemispheres receive the same amount of energy.