Mon Prof Augmenté
Sunlight Lifts a Weight
The sunbeam’s energy is absorbed by the panel and leaves it as an electric current, and the motor turns that current into motion that raises the brass weight. Each link passes the energy on in a new form, while a little of it escapes as heat along the way.
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In the picture
- The tilted photovoltaic panel standing in the sunbeam.
- The red wire carrying current from the panel to the motor.
- The small electric motor winding its spool.
- The brass weight hanging on the thread.
Examples
- A bike dynamo: your legs push the wheel, the dynamo makes a current, and the headlamp glows.
- A phone charger: mains electricity becomes chemical energy in the battery, then light and sound when you play a video.
Key takeaways
- Energy is not used up in a chain; it is handed on in a different form at every step.
- Every step loses some energy as heat, so the useful output is always smaller than the input.
Carry on in the app
Three questions on this lesson. It has left the free week, so its quiz is for subscribers.
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