Bell Work:Bell Work: What causes the seasons?What causes the seasons?

Why is it one season in one part of the Why is it one season in one part of the world and another season in another world and another season in another part of the world at the same time?part of the world at the same time?

What causes a day on Earth? How long What causes a day on Earth? How long is a day on Earth?is a day on Earth?

How can we tell when Earth has gone How can we tell when Earth has gone through a month?through a month?

How Does the Earth Move?How Does the Earth Move? Hold on tight to your desk!! You can’t feel it, Hold on tight to your desk!! You can’t feel it,

but you are traveling at a speed of 30 km per but you are traveling at a speed of 30 km per minute. The earth is actually traveling at this minute. The earth is actually traveling at this speed in an speed in an elliptical pathelliptical path (like an (like an ovaloval) ) around the sun.around the sun.

This path is called an This path is called an orbitorbit..

Each complete orbit, or Each complete orbit, or revolutionrevolution around around the sun, takes the sun, takes 365365¼¼ days, or days, or oneone year. year.

How Does the Earth Move?How Does the Earth Move? The earth has a second type of motion. It The earth has a second type of motion. It

spins or spins or rotatesrotates, like a top., like a top.

Each complete rotation of the earth takes Each complete rotation of the earth takes 24 hours24 hours. This motion gives us . This motion gives us nightnight and and dayday. .

AB C D

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?

SeasonsSeasons The Earth is The Earth is tiltedtilted on its on its

axis axis at a 23.5at a 23.5˚ angle. This ˚ angle. This tilt affects how much tilt affects how much solar solar energyenergy an area receives an area receives as the Earth moves around as the Earth moves around the sun.the sun.

The The seasonsseasons are caused are caused by the tilt of Earth’s axis as by the tilt of Earth’s axis as Earth travels around the Earth travels around the sun. sun.

The Tilt of the Earth and it’s The Tilt of the Earth and it’s rotation around the sun are rotation around the sun are what causes the different what causes the different

seasons.seasons.

Summer: JuneSummer: June

During our summer months the During our summer months the NorthernNorthern Hemisphere has Hemisphere has warmerwarmer temperatures temperatures and longer days because it tilts and longer days because it tilts towardtoward the sun and receives more direct solar the sun and receives more direct solar energy for a longer amount of time. energy for a longer amount of time.

However, the However, the SouthernSouthern Hemisphere has Hemisphere has coolercooler temperatures and shorter days temperatures and shorter days because it is tilted because it is tilted awayaway from the sun. from the sun.

Winter: DecemberWinter: December

During our winter months the During our winter months the Southern Southern HemisphereHemisphere has higher temperatures has higher temperatures and longer days because of it tilts toward and longer days because of it tilts toward the sun and receives more direct solar the sun and receives more direct solar energy. energy.

The The Northern HemisphereNorthern Hemisphere has has lower lower temperaturestemperatures and shorter days because and shorter days because it tilts it tilts awayaway from the sun. from the sun.

Spring and Fall: March & Spring and Fall: March & SeptemberSeptember

NeitherNeither end of end of Earth’s axis is tilted Earth’s axis is tilted toward the sun. toward the sun. BothBoth hemispheres hemispheres receive the receive the same same amounts of amounts of energyenergy..

SeasonsSeasons

BellworkBellwork

How is the Northern Hemisphere How is the Northern Hemisphere facing when we are having winter?facing when we are having winter?

During what season do we have the During what season do we have the longest amount of daylight?longest amount of daylight?

Months: Lunar CalendarMonths: Lunar Calendar We can keep track of months in the We can keep track of months in the

year by the year by the phases of the moonphases of the moon (lunar calendar).(lunar calendar).

The phases begin with the “The phases begin with the “new new moonmoon.”.”

As the Moon moves around the As the Moon moves around the Earth, we get to see more and more Earth, we get to see more and more of the illuminated surface. We see of the illuminated surface. We see the following phases:the following phases: Day 4- Day 4- waxing crescentwaxing crescent Day 7- Day 7- first quarter or half moonfirst quarter or half moon Day 10- Day 10- waxing gibbouswaxing gibbous..

Months: Lunar CalendarMonths: Lunar Calendar Two weeks after the new moon (third week), Two weeks after the new moon (third week),

the moon is now halfway through its the moon is now halfway through its revolution, and now the illuminated half revolution, and now the illuminated half coincides with the one facing the Earth, so coincides with the one facing the Earth, so that we can see a full disk: we have a that we can see a full disk: we have a full full moonmoon on day 14.on day 14.

From now on, until it becomes new again, From now on, until it becomes new again, the illuminated part of the Moon that we can the illuminated part of the Moon that we can see decreases, and we can see the following: see decreases, and we can see the following: Day 18- Day 18- waning gibbouswaning gibbous Day 22- Day 22- Third Quarter or half moonThird Quarter or half moon Day 26- Day 26- waning crescentwaning crescent

Months: Lunar CalendarMonths: Lunar Calendar

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

1. New Moon1. New Moon

The side that Earth sees is completely dark.

Draw a circle and shade the entire circle.

2. Waxing Crescent2. Waxing Crescent

Right side isRight side isilluminated. illuminated.

Left side is Left side is shaded.shaded.

3. 13. 1stst Quarter Moon Quarter Moon

Right side is Right side is illuminated.illuminated.

Left side is Left side is shaded.shaded.

4. Waxing Gibbous Moon4. Waxing Gibbous Moon

Right side Right side is is illuminated.illuminated.

Left side is Left side is shaded.shaded.

5. Full Moon5. Full Moon

The whole The whole moon is moon is illuminated.illuminated.

6. Waning Gibbous6. Waning Gibbous

Left side is Left side is illuminated.illuminated.

Right side is Right side is shaded.shaded.

7. Third Quarter Moon7. Third Quarter Moon

Left side is Left side is illuminated.illuminated.

Right side is Right side is shaded.shaded.

8. Waning Crescent Moon8. Waning Crescent Moon

Left side is Left side is illuminated.illuminated.

Right side is Right side is shaded.shaded.

Review1. 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:Discussion Questions: Which movement of the earth gives Which movement of the earth gives

us our 24-hour day?us our 24-hour day?

Which movement of the earth gives Which movement of the earth gives us our 365us our 365¼¼ day year? day year?

How many complete rotations has How many complete rotations has the earth made this month?the earth made this month?

How many complete revolutions has How many complete revolutions has the earth made since you were born?the earth made since you were born?