Solar Cells and the Seasons

Overview

This lesson uses a practical model to build the idea behind the seasons. By changing the angle of a solar cell to a light source, you can see how the angle of sunlight affects the amount of energy received.

What You Need to Know

• A solar cell transfers light energy into electrical energy.
• The angle of the solar cell relative to the light source affects the voltage produced.
• When light arrives more directly, the energy is spread over a smaller area and the solar cell produces a larger voltage.
• When light arrives at a lower angle, the energy is spread over a larger area and the voltage is lower.
• This gives a simple model for why some parts of the Earth receive more energy from the Sun than others at different times of year.

How to Work Through It

1. Start by revisiting the energy transfer of a solar cell.
2. Measure how the voltage changes as the angle of the cell changes.
3. Record the pattern clearly and describe what happens as the angle becomes less direct.
4. Link the practical pattern to the angle of sunlight reaching the Earth during different seasons.

Check Your Understanding

• What energy transfer takes place in a solar cell?
• Why does a more direct angle usually produce a larger voltage?
• What happens to the energy from the light when the angle becomes more shallow?
• How does this practical help explain the seasons?

Common Mistakes

• Thinking the seasons are caused mainly by the Earth being closer to or further from the Sun.
• Describing the voltage change without linking it to the spreading out of energy.
• Forgetting that the solar cell is a model used to explain a much larger Earth-Sun system.

Next Steps

• Use the practical results to support your explanation of seasonal energy differences.
• Keep the ideas of angle and energy transfer clear because the next lesson adds day-length data.