1. OBJECTIVE: To infer the cause of the seasons.
WHY DO WE HAVE SEASONS?
OBJECTIVE: To infer the cause of the seasons.

2. RESEARCH: Season: Large change in weather and temperature.
4 seasons on Earth:
spring, summer, autumn, winter
Earth’s axis:
Imaginary pole through
center.
Equator:
Imaginary line around the middle of
earth separating northern and
southern hemispheres.

3. THE TILT Summer in the Northern Hemisphere:
Axis is tilted 23.5 degrees toward the sun.
Direct rays of light are very hot.

4. THE TILT Winter in the Northern Hemisphere:
Axis is tilted 23.5 degrees away from sun.
Indirect (slanted) rays of light are
not as hot.

5. EARTH’S SEASONS

6. OUTPUT: Thermometer is Earth and flashlight is Sun.
Make two data lists for changing temperature over time: one for SUMMER and one for WINTER.
If your group is winter, hold the flashlight (sun) at an angle.
If your group is summer, hold the flashlight (sun) pointing straight down.
Every 30 seconds, record the change in temperature.
Graph the results.

7. DATA LISTS Time (min) Winter Temp (C) Summer Temp. (C) .5 1 1.5 2 2.53
3.5 4
4.5 5

8. GRAPH: TEMP VS TIME 30 29 28 27 26 (make two lines, one for 23 22 21
TEMP. 25 summer and one for winter)
(C) 24 23 22 21
TIME (min)

9. QUESTIONS
Which kind of light (direct or indirect) gives the most heat?
Which area on Earth receives the most direct light year round?
What motion of Earth creates night and day?
If Earth’s axis were not tilted, would we still have night and day? Would we still have seasons? (explain each)