Using potatoes to create electric current might seem impossible; however, it is actually quite easy to generate an electrical charge using just a few tubers and a couple of different metals. You can use this "battery" to power a watch for a short time, as a science experiment or just for fun. The composition of the potato allows it to conduct energy, but it keeps the zinc ions of the nail separate from those of the copper, forcing the electrons to move from one end to the other and thus generating electricity. You can make a potato clock with two or more tubers.
Steps
Method 1 of 3: Use Two Potatoes
Step 1. Gather the necessary materials
Before you start assembling the potato clock, you need to get everything you need; most are available in hardware stores or DIY stores, except potatoes, which must be bought from the greengrocer.
- Two potatoes;
- Two pieces of copper wire;
- Two galvanized nails;
- Three crocodile cables (each element consists of two alligator clips connected by a cable);
- A simple low voltage digital clock.
Step 2. Remove the batteries from the watch
Once the assembly is complete, you will need to connect the negative and positive poles of the potato to the terminals inside the clock, instead of the batteries. You do not have to replace the door that closes the battery compartment, in order to have easy access to the terminals with the cables.
- If your watch does not have battery connectors that are clearly identified as positive and negative, differentiate them with a permanent marker based on the location of the battery.
- If instead they are labeled, the positive is usually recognizable by a "+" sign, while the negative terminal by a "-".
Step 3. Insert a nail and a small piece of copper wire into each potato
Start by putting a label on each tuber to identify number 1 and number 2; this detail will prove useful in the course of the experiment. Insert a nail about 2.5 cm into the vegetable, near the end. Repeat the same operation with the segment of copper wire on the opposite end or in any case at the point as far as possible from the nail.
- Each potato should have a nail and copper wire sticking out at opposite ends.
- Make sure the two pieces of metal don't touch inside the tuber.
Step 4. Use the alligator leads to connect the potatoes and the clock
You have to connect the tubers together and then both to the clock using the three cables; in this way, you create a circuit that involves all three elements and through which electrical energy flows. Here's how to make the connections:
- Connect the copper wire of the first potato with the positive (+) terminal of the clock located inside the battery compartment. For this operation use a crocodile cable.
- Join the nail from the second potato to the negative end of the clock.
- Using the third wire with clamps, join the nail of the first vegetable to the copper wire of the second.
Step 5. Check the connections and set the clock
As soon as you join the two potatoes with the wire, the clock should light up. If nothing happens, check the connections to make sure they are correct and that there is direct contact between the metals.
This method does not allow the clock to run for long; once you are sure that it works you have to unplug it if you are hoping to present your experiment in class or at a science show
Method 2 of 3: Use Three Potatoes
Step 1. Put the material together
As with any experiment, you must first get everything you need. You can buy most of the materials at a hardware store or home improvement center, or you may already have some at home. Get:
- Three potatoes;
- Three copper strips or, alternatively, three euro cent coins;
- Three galvanized nails;
- Four crocodile cables (there are eight clamps in all);
- A low voltage digital clock.
Step 2. Insert a nail into each potato
Just like in the previous experiment, each potato must have a galvanized nail inside it. Put it in the end of the tuber and let it penetrate about 2.5 cm. Repeat the process with the other two vegetables.
- Make sure the nail isn't sticking out of the other side of the potato.
- Do not press the nail hard enough to contact the copper strip or dime you insert later.
Step 3. Slip the copper strip into each potato
Press it into the opposite end of the nail. If you have decided to use a coin, make sure that half of it remains visible above the skin of the tuber, as you will need to attach the crocodile clip to it later.
- If you are using a copper strip, do not insert it far enough into contact with the nail.
- Try to keep the copper away from the nail as much as possible.
Step 4. Connect the potatoes in series
Once the nails and pieces of copper are in the ends of each vegetable, this procedure allows for more electrical current to be generated. Line up the vegetables in front of you and use the alligator leads to connect them in series. Make sure the potatoes are lined up the same way, with the nails all facing in one direction and the copper pieces in the other.
- Attach an alligator clip to the copper piece of each tuber and connect the one on the other end of the cable to the nail of the next potato.
- Repeat the process until each side potato is joined to the central one by means of a wire.
Step 5. Join the tubers to the clock
The two outer potatoes should have only one alligator cable connecting them to the central one. Attach one clamp to the free nail of one potato and another separate clamp to the copper piece of the second potato.
- Connect the alligator clip located at the other end of the wire connected to the nail to the positive terminal of the battery compartment.
- Then join the other clamp located at the end of the wire connected to the copper piece to the negative terminal of the battery.
Step 6. Check the connections and set the clock
When both clamps are attached to the positive and negative terminal, the clock should light up. If not, check each connection, make sure it is secure and that the metal of the clamp is in contact with the copper.
- When the connections are secured, the clock should work.
- You should unplug the clock, to avoid running out of all the chemical energy of the potatoes, in case you have to show your experiment at a science fair or in the classroom.
Method 3 of 3: Troubleshoot
Step 1. Check the cable connections
If the clock is not working, there may be problems in the connections between the potatoes and the clock. Check that each connection is secure and that there is no material separating the metal of the clamp from the nail or copper. You should also check that you have respected the correct order; the cables should be connected from positive to negative. The nail of one potato must be connected to the copper of the next and so on.
- Try replacing the coins with copper strips, to ensure a strong connection.
- Check that each terminal is perfectly connected to its respective cable.
Step 2. Add another potato
If the circuit is perfectly closed, but the clock still doesn't work, the potatoes may not produce enough potential difference to power it. You can use a multimeter or voltmeter to check the voltage, if you have them, or you can try adding another tuber in series to the battery, to increase the energy generated.
- Connect the additional potato as you did with the others: attach the clamp that comes from one piece of copper to the nail of the next tuber and then the clamp that comes from the copper piece of this second potato to the clock or the adjacent potato.
- If the watch does not work despite the addition, there may be a problem with the connection or with the watch itself.
Step 3. Soak the potatoes in the Gatorade
By soaking them overnight in this soda, you increase their conductivity and allow them to power the clock. Gatorade contains electrolytes that help pass current through each tuber, but you have to wait all night to make sure the electrolytes reach the potato's core.
Gatorade also contains phosphoric acid, which increases electrical conduction properties
Step 4. Replace the potatoes with a fruit that conducts electricity
If you can't get the clock to work with potatoes, you can try another vegetable. Lemons and oranges are perfect for this purpose; put the nail and copper strip into the fruit, just like you did with potatoes.
By rolling the fruit on the table before making the connections, you can break the internal pulp by making the juice move more easily; consequently, electricity can also travel with greater fluidity
Step 5. Make sure you have the right materials
If you use the incorrect ones, you may encounter many difficulties and also fail to assemble the potato clock. Check what you buy, look at the packaging, to be sure it's what you need.
- Read the writing on the nail packaging to make sure they are galvanized. Although almost everyone on the market is, this experiment would not work with non-galvanized nails.
- Make sure the watch runs on 1-2 volts and can accommodate the classic coin cell battery. You can determine the voltage you need by reading the product information sheet found on the packaging.
Warnings
- Don't eat the potatoes you used for this project.
- Small children should be supervised when performing this experiment, as the nails and metal wires are sharp and could cause injury if handled incorrectly. Don't lose sight of the little ones even while taking out the batteries.
