How Far Should We Tilt?

You have learned that Earth’s axis is tilted at 23.5 degrees. The tilt and the revolution give us our seasons. What if the angle of tilt were different? How would this change the angle at which light from the sun strikes Earth, the length of daylight, and the seasons?

Materials:

• Globe
• Flashlight or lamp
• Science Journal

Procedure

1. Tilt the globe to its 23.5 degree angle. Model Earth’s revolution around the sun (flashlight or lamp). Observe where the light strikes Earth for each season. Record what you observe in your in your science journal.
2. Tilt the globe so its axis is straight up and down. Observe where the light strikes Earth for each season. What are the differences in daylight and season as a result of this change? Record these differences in your science journal.
3. Tilt the globe to a 90 degree angle. Observe where the light strikes the Earth for each season. What are the differences in daylight and seasons as a result of this change? Record your observations in your science journal.
4. Try out more angles of your choice and record your observations in your science journal.

Analysis

1. Draw the earth with its correct tilt. Label the degrees.
2. What would happen if the earth were not tilted?
3. Explain how the amount of energy received from the sun affects the seasons.