Bell Work: What causes the seasons? Why is it one season in one part of the world and another season in another part of the world at the same time? What causes a day on Earth? How long is a day on Earth? How can we tell when Earth has gone through a month?

How Does the Earth Move? Hold on tight to your desk!! You can’t feel it, but you are traveling at a speed of 30 km per minute. The earth is actually traveling at this speed in an elliptical path (like an oval) around the sun. This path is called an orbit. Each complete orbit, or revolution around the sun, takes 365¼ days, or one year.

How Does the Earth Move? The earth has a second type of motion. It spins or rotates, like a top. Each complete rotation of the earth takes 24 hours. This motion gives us night and day. In the picture, City C is experiencing sunrise. Which city has had sunlight for about one hour? Which cities are still dark? Which city will be the next to experience sunrise? A B C D

Seasons The Earth is tilted on its axis at a 23.5˚ angle. This tilt affects how much solar energy an area receives as the Earth moves around the sun. The seasons are caused by the tilt of Earth’s axis as Earth travels around the sun.

The Tilt of the Earth and it’s rotation around the sun are what causes the different seasons. Check this out!

Summer: June During our summer months the Northern Hemisphere has warmer temperatures and longer days because it tilts toward the sun and receives more direct solar energy for a longer amount of time. However, the Southern Hemisphere has cooler temperatures and shorter days because it is tilted away from the sun.

Winter: December During our winter months the Southern Hemisphere has higher temperatures and longer days because of it tilts toward the sun and receives more direct solar energy. The Northern Hemisphere has lower temperatures and shorter days because it tilts away from the sun.

Spring and Fall: March & September Neither end of Earth’s axis is tilted toward the sun. Both hemispheres receive the same amounts of energy.

Seasons

Bellwork How is the Northern Hemisphere facing when we are having winter? During what season do we have the longest amount of daylight?

Months: Lunar Calendar We can keep track of months in the year by the phases of the moon (lunar calendar). The phases begin with the “new moon.” As the Moon moves around the Earth, we get to see more and more of the illuminated surface. We see the following phases: Day 4- waxing crescent Day 7- first quarter or half moon Day 10- waxing gibbous.

Months: Lunar Calendar Two weeks after the new moon (third week), the moon is now halfway through its revolution, and now the illuminated half coincides with the one facing the Earth, so that we can see a full disk: we have a full moon on day 14. From now on, until it becomes new again, the illuminated part of the Moon that we can see decreases, and we can see the following: Day 18- waning gibbous Day 22- Third Quarter or half moon Day 26- waning crescent

Months: Lunar Calendar A while after four weeks (29.5 days, more precisely) the illuminated half of the Moon again faces away from us, and we come back to the beginning of the cycle: a new moon.

1. New Moon The side that Earth sees is completely dark. Draw a circle and shade the entire circle.

2. Waxing Crescent Right side is illuminated. Left side is shaded.

3. 1st Quarter Moon Right side is illuminated. Left side is shaded.

4. Waxing Gibbous Moon Right side is illuminated. Left side is shaded.

5. Full Moon The whole moon is illuminated.

6. Waning Gibbous Left side is illuminated. Right side is shaded.

7. Third Quarter Moon Left side is illuminated. Right side is shaded.

8. Waning Crescent Moon Left side is illuminated. Right side is shaded.

Review 1. How long does it take for the earth to go around the sun? What are the two names for that path? 2. How long does it take for the earth to experience one day and one night? What are the two names for that time? 3. Define and draw the four types of tides. 4. Our calendar is based on what? 5. Tidal range is greatest during… 6. What is a tidal bore? 7. In the summer we have longer days and ____ temperature. 8. What are seasons caused by? 9. What do you call the difference between the levels of water at high tide and low tide? 10. The gravitational pull of the moon on earth is greatest on_____.

Discussion Questions: Which movement of the earth gives us our 24-hour day? Which movement of the earth gives us our 365¼ day year? How many complete rotations has the earth made this month? How many complete revolutions has the earth made since you were born?