Sun & Wind

How much power can they give?

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Sunlight: about 1,000 W/m² at noon. Panels convert about 20%.
• Wind power $= \tfrac12\rho A v^3$: doubling the wind speed gives 8× the power.
• The Betz limit: no turbine can capture more than 59% of the wind’s power.

Steps

1. Sunlight
2. A rooftop panel
3. The wind’s cube law
4. The Betz limit
5. A year of wind
6. Calm versus breezy