A battery is essentially a container filled with chemicals that produce electrons. If you look at any battery, you’ll notice that it has two terminals, marked positive (+) and negative (-). The two different wires are separated by a load, which consumes the battery’s power. Electrons flow from the battery into a wire, and must travel from the negative to the positive terminal for the chemical reaction to occur. That is why a battery can sit on a shelf for a year and still have plenty of power. Unless electrons are flowing from the negative to the positive terminal, the chemical reaction does not take place.
Supplies from the EHA Science Box:
- 2 Lemons
- 6 Pennies
- 6 Zinc-galvanized nails
- 4 Alligator clips
- Low power LED light
- A few batteries as examples
EHA Activity Book:
Show your students a few batteries and ask them to describe the parts of each. Ask students to draw the battery in the box under “Batteries”. Be sure to add a plus and minus to indicate positive and negative.
Definition: A battery is a container filled with chemicals that produce electrons.
Caveat: Other EHA campuses have had a tough time making the light illuminate. This experiment may not work but it is important enough to keep in the program because it teaches so many concepts.
- Discuss the definitions of battery functions and ask the student to write short description in their EHA Activity Book
- Ask students to draw a picture of their fruit battery
- Slice the lemons into four pieces.
- Use the knife to cut a penny sized slit in all of the lemon pieces
- Insert a penny halfway into the slits you cut
- Opposite of the penny push a zinc-galvanized nail into each of the lemons without letting the nail and penny touch in or out of the lemon
- Using the alligator clips connect a nail on one lemon to the penny of another lemon
- Repeat with all of the lemons the last penny and nail should have one unused side of the alligator clip
- Attach the two loose alligator clips to the LED light
All batteries are composed of two different metals suspended in acidic solution. With the fruit-powdered battery, the two metals were the zinc from the galvanized nails and the copper pennies, while the acidic solution comes from the lemons. The pennies and nails function as electrodes, the part of the battery where the electrical current passes through; allowing the electrons to flow out of the pennies, through the lemons, and into the nail. When you connected the LED light it became the load, which completed the circuit, making the electrical current pass through the light powering it.
- Ask your students to try other configurations. Why did they work or not work?
- Ask your class to make one big battery. How many lights can your students light at one time?