What it shows
Two different metals in an acidic juice make an electric cell, turning chemical energy into electrical energy. One lemon gives less than one volt, so several are joined in series to light an LED.
This idea has a short entry only. For the science behind it, read the sentence above with your textbook and ask your teacher to explain the law or idea it shows, so you can describe it in your own words.
Materials
- Four lemons or potatoes
- Copper strips or coins, and galvanised (zinc-coated) nails
- Wires with crocodile clips
- An LED and a multimeter
Safety
For this project: Do not eat the fruit afterwards.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesHow to go about it
Numbered steps have not been written for this idea yet. Plan it with your teacher: sketch the design with measurements, build one part at a time, test each part, and write every observation with the date. The free ebooks below have step-by-step projects of the same kind.
Take it further
Does the distance between the metals, or the type of fruit, change the voltage?
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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Find out more about chemistry
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