The document discusses several key facts about Earth's rotation: - Earth spins on an imaginary axis, completing one rotation every 24 hours at a speed of over 1,000 mph. - Earth's rotation causes day and night and influences the number and placement of time zones around the world. - Earth bulges slightly at the equator due to the centrifugal force of its rotation. - Earth's tilted axis and yearly orbit around the sun influence the seasons and amount of sunlight different areas receive through the year.

1. Earth’s Rotation
Mrs. Burch

2. Do you know?
• What causes day & night?
• What percent of the earth is always lit by the sun?
• Which direction the Earth spins?
• How many time zones are in the world?
• How fast the Earth spins?
• What is the true shape of the Earth?
• Why it’s colder at the North and South poles?

3. Earth’s
Rotation
The Earth spins
on an imaginary
pole that we call
an “axis”.
Click image to view Earth’s rotation.

4. Earth’s Rotation
If you were to
look down at the
North Pole, you
would see that the
Earth spins
counter-
clockwise. Click image to view Earth’s rotation.

5. The direction of Earth’s rotation is why
Florida is 2 hours ahead of Arizona.

6. Earth is tilted 23.5 degrees in
relation to the sun.

7. The spinning of the Earth is called “rotation”. It
takes Earth 24 hours to make one complete
rotation.

8. The speed of this rotation is 1,038 miles
per hour!

9. The Earth is in the shape of a
sphere that bulges out a little at
the equator.

10. Can you figure out WHY it
bulges at the equator?

11. Watch a demonstration of a
sphere bulging out due to
spinning.
• https://youtu.be/FRgCF3WStfU

12. • Because of Earth’s round shape, sunlight hits the earth
at angles.

13. • The places that get the
most direct sunlight are
the warmest. These
places are between the
Tropic of Capricorn
and the Tropic of
Cancer.

14. • The places that get the most direct sunlight are the
warmest. These places are between the Tropic of
Capricorn and the Tropic of Cancer.

15. Because the Earth is tilted, there are times of the
year when Antarctica and the North Pole have
sunlight all day and night long in the summer, and
no sunlight at all in the winter.

16. Watch this video to see why:
https://youtu.be/m4NJHI3dwTU

17. Have you heard of Lahaina Noon in
Hawaii?

18. Lahaina Noon is when Hawaii is getting direct
sunlight. In other words, the sun is directly
overhead during Lahaina Noon.

19. • On any given date, there is just 1 place on the planet
where sun rays hit Earth straight on (90o angle). All other
places are getting sunlight at an angle.

20. It is called the “sub
solar point”. The sun is
directly overhead for a
brief amount of time.
What do you notice?

21. What does “subsolar” mean?

22. What does “subsolar” mean?
sub = under or below
solar = sun

23. So, “subsolar” means “under the
sun”.

26. Only places that
are between the
Tropic of Cancer
and the Tropic of
Capricorn can be
a subsolar point.
It depends on the
time of the year.

27. Hawaii is a subsolar
point one day in May
and one day in July
every year. Hawaiians
call this “Lahaina
noon”. Notice that at
Lahaina noon, the statue
casts a shadow that is a
perfect circle.

29. https://youtu.be/QI9ta7qkazU
Watch how the rotation of the
Earth affects daytime and night
time.

30. Who would see the sun rising in
the morning first...people in New
York, or people in California?

31. At any given time, half of the Earth is
in daytime and half is in night time.

32. Watch the video on the next slide
to understand how the rotation of
the Earth affects what time it is.

33. https://youtu.be/widWLhIIbzs

34. There are 24 time zones.

35. https://youtu.be/hPpWCTHjzQI
How can a plane fly from
Tuesday to Monday? Reason:
The International Date Line.

36. The Earth’s rotation also affects
how we see the stars in the night.
https://youtu.be/HsJxGpDmJrQ

37. The only star that doesn’t seem to
move is the North Star, also
called “Polaris”.
https://youtu.be/XTTDWhky9HY

38. Polaris is directly above the
North Pole.
https://youtu.be/xS-9JI6Wxr4

39. Test yourself:

40. What time of the day would it be
where the X is?

41. Answer: Midnight

42. What time would it be where the X is?

43. Answer: Sunrise

44. What time would it be where the X is?

45. Answer: Sunset

46. What time would it be where the X is?

47. Answer: 12:00 Noon

48. If it was sunrise, about how many
hours would have to go by for it
to be sunset?

49. If it was sunrise, about how many
hours would have to go by for it
to be sunset?
Answer: About 12 hours

50. If it was midnight, about how
many hours would have to go by
for it to be noon?

51. If it was midnight, about how
many hours would have to go by
for it to be noon?
Answer: About 12 hours

52. https://youtu.be/i2mec3vgeaI
The Coriolis effect is another
effect of Earth’s rotation.

53. The End