Integrated Science Names ____________________________________________
(2-4 group members)
Purpose: To determine how daylight changes throughout the seasons, depending on its tilt, and where the sun is located at different times of the year with a 23.5
o
tilt.
Materials: Globe with tilt board, flashlight, ruler, protractor, cardboard ring, wet erase markers, modeling clay, 3 toothpicks
Procedure: Note: This lab is best done in a darkened room .
Part 1
A.
Locate the equator, Tropics of Cancer and Capricorn, and Arctic and Antarctic
Circles.
B.
Set the angle of the globe to 0 (straight up and down). Slide the cardboard ring around the globe to the poles. Stand back about 1 meter and aim your flashlight at the equator. The light should be parallel to the floor.
1.
The side facing the light is ________, the other side is __________.
(day or night?)
2.
Where is the light the strongest (brightest)? _______________
C.
Determine the hours of daylight by counting the number of longitude lines visible on the lighted side of the cardboard ring and multiplying by 2 hours for each line you count. For example, if you count 4.5 lines of longitude, 4.5 x 2 hours = 9 hours of daylight!
3.
How many hours of “daylight” does the Equator experience? ______
4.
How many hours of “daylight” does the Tropic of Cancer experience? ______
5.
How many hours of “daylight” does the Arctic Circle experience? ______
6.
What term relating to seasons means “equal night”? ____________
7.
Which two dates does this position represent? __________ and ___________
8.
Which two seasons does this position represent? __________and __________
D.
Using 3 pea-size pieces of modeling clay and 3 toothpicks, attach the 3 toothpicks to your globe, one at the Equator, one at each of the Tropics.
9.
Aiming your flashlight at the equator, measure the length (in cm) of the shadows, if any, at each position: a.
Equator ____ b. Tropic of Cancer ____
E.
Remove the clay and toothpicks. c. Tropic of Capricorn ____
Part 2
A.
Using your protractor, tilt your globe about 23-25 o from vertical. Position the globe so that you are looking at the Tropic of Cancer near the center. Slide the cardboard ring so that it rests on the Arctic Circle. Aim your flashlight directly at the globe, standing back about 1 meter. The light should be parallel to the floor.
10.
Where is the light the strongest (brightest)? __________________

11.
Which pole is getting more light energy? ______
B.
Determine the daylight hours by counting how many lines of longitude visible and multiplying by 2 hours for each interval. Estimate for half intervals.
12.
How many hours of “daylight” does the Equator experience? ______
13.
How many hours of “daylight” does the Tropic of Cancer experience? ______
14.
How many hours of “daylight” does the Arctic Circle experience? ______
15.
How many hours of “daylight” does the Antarctic Circle experience? ______
16.
What date does this position represent? __________
17.
What season does this position represent (for the North)? __________
C.
Replace or straighten the toothpicks from Part 1, Step D above if necessary.
18.
Aiming your flashlight at the Tropic of Cancer, measure the length (in cm) of the shadows, if any, at each position: a.
Equator ____ b. Tropic of Cancer ____ c. Tropic of Capricorn ____
Part 3
D.
Turn the board your tilted globe is mounted on 180 o so that when you aim your flashlight, it should now be directly over the Tropic of Capricorn. Be sure the cardboard ring is resting on the Arctic Circle. Aim your flashlight directly at the globe, standing back about 1 meter. The light should be parallel to the floor.
19.
Where is the light the strongest (brightest)? ___________________
20.
Which pole is getting more light energy? ______
A.
Determine the daylight hours by counting how many lines of longitude visible and multiplying by 2 hours for each interval. Estimate for half intervals.
21.
How many hours of “daylight” does the Equator experience? ______
22.
How many hours of “daylight” does the Tropic of Cancer experience? ______
23.
How many hours of “daylight” does the Arctic Circle experience? ______
24.
How many hours of “daylight” does the Antarctic Circle experience? ______
25.
What date does this position represent? __________
26.
What season does this position represent (for the North)? __________
C. Replace or straighten the toothpicks from Part 1, Step D above if necessary.
27.
Aiming your flashlight at the Tropic of Capricorn, measure the length (in cm) of the shadows, if any, at each position: a.
Equator ____ b. Tropic of Cancer ____ c. Tropic of Capricorn ____
Part 4
Experiment at more extreme tilt angles. Describe what you did and what you found out.
Include some measurements! Attach paper if necessary.

Use a dampened paper towel to erase any marks you may have made on the globe, take off the toothpicks and clay, and return all your materials to your teacher.
Integrated Science Name ____________________________
1.
How long (in number of days or months) is it between an equinox and a solstice? ______
2.
What is the difference between rotation and revolution ? Include how long each is .
3. How does the amount of solar energy (sunlight) received in Eagle River, Alaska, change as the Earth revolves around the Sun? Use some data from this lab to support your answer.
3.
Which regions of the Earth receive solar energy for only part of the year? _________
4.
Where is the change in solar energy (as measured by daylight hours) greater—at the poles or at the equator? Explain your answer.
5.
Is there any time in the course of a year that the entire Earth seems to receive the same amount of solar energy? If so, WHEN? If not, WHY?
6.
When the North Polar regions are receiving lots of sunlight, what is happening in the
South Polar regions?
7.
Study the image of the revolution of the Earth around the Sun below. Label each of the seasons at the four positions shown. Put a date under each.
8.
Describe “equinox.” Include what happens and WHEN.

9.
Describe “solstice.”
Include what happens and WHEN.
10.
Describe how would our seasons be different if the Earth were NOT tilted.
11.
Where on the Earth is the average amount of solar energy the greatest throughout the year?
12.
Why is it always warmer in the Tropics and the Equatorial regions?
13.
Why is Alaska’s winter sometimes called the “arctic night?”
14.
What are TWO reasons we have seasons?