Why do we Why do we have seasons?have seasons?

Two Movements of EarthRotation:

•The Earth rotates on its axis

•One day on Earth is one rotation of the Earth.

•Day vs. Night Demo– (Globe &Flashlight)

Earth’s Revolution

• Earth revolves around the sun

• It takes the Earth 365 days to travel or revolve around the sun once.

True or False?1. The Earth orbits the sun in a circular path?

2.Seasons are caused by the distance each planet is to the sun.

3.The Earth is closest to the sun in January.

4.Both the northern and southern hemispheres enjoy summer at the same time of year.

http://www.youtube.com/watch?v=p0wk4qG2mIg

The Reason for the Seasons…Bill Nye The Science Guy:http://www.youtube.com/watch?v=KUU7IyfR34o

Q: What causes the seasons?A: Tilt of the Earth's axis.

Globe and Sun Position Demo: Identify the season…

Solstices—Summer vs. Winterhttp://www.brainpop.com/science/earthsystem/solsticeandequinox/

Solstices—Summer vs. Winterhttp://www.brainpop.com/science/earthsystem/solsticeandequinox/• Solstice = when the tilt of the Earth's axis is oriented directly

towards or away from the Sun

– Winter solstice is the shortest day of the year. – Summer Solstice is the longest day of the year.

Equinoxes—Spring vs. Fall

• Equinox literally means "equal night"

• A day lasts 12 hours and a night lasts 12 hours at all latitudes.

• This occurs twice a year.

Review: What Season Is It?