Seasons - Day Length
Name ____________________________________ Period _____ Date _________________
Procedure:
Total Distances:
1. Use a mini-trundle wheel to measure the whole circumference (in cm) of the world at the Arctic Circle.
2. Record the measurement in the table for the each date in the Total Distance column.
3. Repeat the whole circumference measurements for the other 4 latitudes (the Tropic of Cancer, the
Equator, the Tropic of Capricorn, and the Antarctic Circle).
Daylight Distances:
1. While standing in between the “sun” in the center of the classroom and one of the dates on the wall,
hold the globe so the north pole is titled toward the back of the classroom.
2. Measure the part of the circumference (in cm) at the Arctic Circle that is lit by the sun. This represents
the amount of hours of daylight this latitude will get on that day.
3. Record the measurement in the Daylight Distance column.
4. Repeat for each of the latitudes.
Hours of Daylight:
1. Calculate the percentage (%) of daylight and number of daylight hours by following the formulas in the
table.
66.7o N
June 21
23.5o N
0o
23.5o S
66.7o S
Hours of Daylight on June 21
Location
Arctic Circle
(66.7o N)
Tropic of Cancer
(23.5o N)
Equator (0o)
Tropic of Capricorn
(23.5o S)
Antarctic Circle
© 2005 K.Corbett
Daylight
Distance
(B)
Total
Distance
(A)
% Daylight =
B
A
Number of
Daylight hours =
% Daylight x
24 hours
(66.7o S)
66.7o N
23.5o N
0o
September 20
23.5o S
66.7o S
Hours of Daylight on September 20
Location
Arctic Circle
(66.7o N)
Tropic of Cancer
(23.5o N)
Equator (0o)
Tropic of Capricorn
(23.5o S)
Antarctic Circle
(66.7o S)
© 2005 K.Corbett
Daylight
Distance
(B)
Total
Distance
(A)
% Daylight =
B
A
Number of
Daylight hours =
% Daylight x
24 hours
66.7o N
23.5o N
December
21
0o
66.7o S
23.5o S
Hours of Daylight on December 21
Location
Arctic Circle
(66.7o N)
Tropic of Cancer
(23.5o N)
Equator (0o)
Tropic of Capricorn
(23.5o S)
Antarctic Circle
(66.7o S)
© 2005 K.Corbett
Daylight
Distance
(B)
Total
Distance
(A)
% Daylight =
B
A
Number of
Daylight hours =
% Daylight x
24 hours
66.7o N
23.5o N
0o
March 20
23.5o S
66.7o S
Hours of Daylight on March 20
Location
Arctic Circle
(66.7o N)
Tropic of Cancer
(23.5o N)
Equator (0o)
Tropic of Capricorn
(23.5o S)
Antarctic Circle
(66.7o S)
© 2005 K.Corbett
Daylight
Distance
(B)
Total
Distance
(A)
% Daylight =
B
A
Number of
Daylight hours =
% Daylight x
24 hours
Conclusion/Analysis:
1. On what day do the following latitudes have the highest number of daylight hours?
Arctic Circle? ___________________ Tropic of Cancer? ___________________
Antarctic Circle? ___________________ Tropic of Capricorn? ___________________
2. Explain why some of your answers in question #1 are on different days.
3. On what day do the following latitudes have the lowest number of daylight hours?
Arctic Circle? ___________________ Tropic of Cancer? ___________________
Antarctic Circle? ___________________ Tropic of Capricorn? ___________________
4. Explain why some of your answers in question #3 are on different days.
5. What do you notice about the hours of daylight for March 20 for those 5 latitudes?
6. What do you notice about the hours of daylight for September 20 for those 5 latitudes?
7. Explain why the answers for questions #5 and #6 are that way.
8. So, who cares? I mean, what does it matter if there are more daylight hours at some times of
the year than others? What does that have to do with the seasons?
Answer this question: How does a higher number of daylight hours affect the coldness and
hotness of our weather?
© 2005 K.Corbett
9. What do you notice happens to the number of daylight hours on June 21 as you go from the
south pole to the north pole? Explain why that is.
10. What do you notice happens to the number of daylight hours on December 21 as you go from
the south pole to the north pole? Explain why that is.
11. Fill in the table below. Hint: fill in the June 21 and Dec 21 data first.
Northern or
Southern
Hemisphere?
What Season is it on…
March 20
June 21
Sept 20
Dec 21
Arctic Circle
Tropic of
Cancer
Equator
Tropic of
Capricorn
Antarctic Circle
What if the Earth weren’t tilted?
o
What would happen if we took away the tilt of the Earth making a 0 tilt in the Earth? Let’s look at
how that would affect the Earth. You can use a globe to help you visualize, but it is not necessary to
re-measure all the data.
1. On what date(s) would your city have 12 hours of day and 12 hours of night?
2. On what date(s) would your city have the highest number of hours of daylight?
3. On what date(s) would your city have the lowest number of hours of daylight?
4. What would the seasons be like on earth if the earth had no tilt?
© 2005 K.Corbett
© 2005 K.Corbett