Ice Tray Battery!

Key Concepts

Activity Directions:

Take the end of a 4-inch copper wire and wrap it around a nail for a few revolutions. Aim to have around 2 inches of the wire wrapped around the nail and 2 inches of the wire hanging off the side of the nail.
Fill in a 2 x 3 grid of the ice cube tray with vinegar. There should now be 6 sections containing vinegar.
We will now create a circuit by linking the 6 sections filled with vinegar with our nails and wires (image below for reference).
1. Take a nail and place it into the bottom-right section, and let the straight portion of the wire connected to the nail sit in the bottom-middle section.
2. Place a nail into the bottom-middle section, and let the straight portion of the wire sit in the bottom-left section.
3. Place a nail into the bottom-left section, and let the straight portion of the wire sit in the top-left section.
4. Place a nail into the top-left section, and let the straight portion of the wire sit in the top-middle section.
5. Place a nail into the top-middle section, and let the straight portion of the wire sit in the top-right section.
There should be both a nail and a wire in contact with each section of the tray except for the top-right and bottom-right sections. The arrangement should look like this:
Place 1 leg of the LED into the top-right section and the other leg of the LED in the bottom-right section.
The LED lights up! (If the LED doesn’t light up, rotate the LED 180 degrees around so that the legs are in the opposite sections.)

Example arrangement of the nails and wires

Discussion Questions & Science Explanations:

What are LEDs and why do they light up?
1. LEDs are small light bulbs that emit light when electrons move through a material inside, emitting light.
Why is vinegar used to fill in the ice cube sections?
1. Vinegar is an electrolyte, a solution that is capable of conducting electricity.
Where does this flow of electrons come from?
1. We used two different metals in this activity: copper (from the wire) and zinc (from the nail).
2. Copper atoms and zinc atoms are both made up of tiny particles called protons, neutrons, and electrons. One property about copper is that it likes to hold onto electrons more strongly than zinc.
3. When the zinc from the nail and copper from the wire are both submersed into the vinegar, and the circuit is closed by placing the LED into the ice cube tray, electrons can move from the zinc to the copper. Recall that copper “pulls” the electrons from zinc because it holds onto electrons more strongly than zinc. This results in a current of electrons passing through the circuit.
Why does the LED not light up when its legs are oriented the wrong way?
1. An LED only allows current to flow in only one direction.
2. When the legs of the LED are “flipped” and not oriented correctly, an electric current will not flow through the LED, and the LED will not light up.

Additional Experimentation:

Try using water instead of vinegar. Does the LED still light up?
Instead of using a 2x3 grid, create a larger circuit by using more sections of the ice cube tray. Is the LED brighter than before? Is it dimmer?

Published 8.14.2020

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