1. Seasons, Day & Night, and Tides

2. Discuss with your partner: What is the reason for the change of seasons?

3. The seasons and their days come and go as the Earth rotates and revolves.seasons What is the difference between the Earth’s rotation and revolution?

4. Rotation: It takes 24 hours for the Earth to spin around once on its axis. Revolution: It takes 365 days for the Earth to travel once around the Sun.

5. Rotation: spin of object on its axis rotates counter-clockwise = west to east = why sun appears to rise in the east and set in the west for Earth = 24 hrs. =1 day responsible for day vs. night Revolution: also called an orbit Revolves counter-clockwise Revolution is the path of one object around another Earth around sun ≈ 365 days = 1 year moon around Earth ≈ 1 month

6. The TILT is the reason for seasons! The Earth is tilted on its axis by 23.5.° As a result, the hemisphere that is tilted toward the sun receives more direct sunlight = more heat. causes longer daylight hours hotter temperatures = summer! The hemisphere tilted away from the sun experiences winter.

7. The changing seasons have nothing to do with Earth’s distance from the Sun! It is the 23.5º tilt of the Earth’s axis that causes the Sun’s light to strike the surface at different angles during different times of the year.

8. During the winter, the Northern Hemisphere is tilted away from the sun. As a result, the angle at which the sun’s rays hits the Northern Hemisphere is decreased. This causes cooler temperatures as the sunlight is spread over a larger area. During the summer, the Northern Hemisphere is tilted toward the sun and will experience more concentrated light. This will result in longer days and warmer temperatures.

9. Light has a scattering effect in the winter Light is more direct and concentrated in the summer http://www.nmm.ac.uk/server/show/conMediaFile.5464

10. For the Northern Hemisphere! = Equal hours of day and night = most daylight hours = least daylight hours

11. Direct, concentrated light = Summer Indirect, scattered light = Winter

12. The Earth is tilted on its axis by 23.5.°

13. http://www.nmm.ac.uk/server/show/conMediaFile.5440

14. Would a December vacation be called “winter break” in South America? Discuss with your partner and be ready to explain why or why not.

15. No! - It is not winter at this time in the Southern Hemisphere. Right now the Southern Hemisphere is tilted towards the sun, receiving direct rays and the warmth of summer.

16. Tides Tide = the daily rise & fall in ocean water level high and low tides occur twice daily high tides are caused by the gravitational pull of the moon & sun, causing the ocean water to “bulge” away from the Earth the moon has a greater impact because it is closer than the sun. High tide occurs on the side facing the moon, but it also occurs on the opposite side. This is because the moon is also pulling the Earth away from the water on the other side.

17. Low Tide High Tide Low Tide High Tide Gravitational pull of the moon Tidal bulge

18. When the sun, moon and earth all line up, we get the highest high tides and the lowest low tides. These are called Spring Tides. on and sun pull together = largest tides moon and sun pull against each other = weakest tides When the sun, moon and earth are at a ninety-degree angle, then the moon and the sun are exerting forces in opposite directions. This results in the lowest high tides and the highest low tides called Neap Tides. Spring and Neap Tides

19. What moon phases are present during Spring Tides? What moon phases are present during Neap Tides? FULL MOO N NEW MOO N 1 st Quarter MOON 3 rd Quarter MOON