Science experiment gone wrong: lemons, potato, carrot as battery - please help?

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sumacveneneux

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Hello the Forum,

I would like to ask your advise please? My son is busy with a science experiment - to use a lemon, potato, carrot as a battery to power a small car. We followed all the instructions, except that we can't find success. We adapted the experiment - took the car apart and used the veg as the car, no luck. What are we doing wrong? Is there any way to prove that electrical current is generated by the veg? I'm at my wits end with this (not a science person at all!)

Failing that, any impressive experiments that we can do in a short period of time where conclusions are made?

Thank you in advance!
 
Connect a multimeter to the wires from your veg batter. If theres current, it will show up.
 
Youtube man. Last time I did this I needed 3 lemons in series to make small DC motor run.
 
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Thanks Sysem, we will get one over the weekend, BUT would still want to have success on the experiment. We can see that there is charge, as the potato goes black. Just not enough. It has been suggested that we soak the potato in lemon juice to increase the charge.

lcbxx - youtube lies! I'm sure of it. I think the guy put a battery in his potato. We've re-hashed the darn experiment so many times now, it's been 4 days of experimenting. :cry:
 
sumacveneneux said:
Thanks Sysem, we will get one over the weekend, BUT would still want to have success on the experiment. We can see that there is charge, as the potato goes black. Just not enough. It has been suggested that we soak the potato in lemon juice to increase the charge.

lcbxx - youtube lies! I'm sure of it. I think the guy put a battery in his potato. We've re-hashed the darn experiment so many times now, it's been 4 days of experimenting. :cry:
Click to expand...
You need something copper for the + terminal and a standard nail for the - terminal. We used a 5c for the copper bit. I do not know how much voltage the 3 lemons produced but the motor ran at medium speed, not consistent though. The copper is the key.
 
sumacveneneux said:
Hello the Forum,

I would like to ask your advise please? My son is busy with a science experiment - to use a lemon, potato, carrot as a battery to power a small car. We followed all the instructions, except that we can't find success. We adapted the experiment - took the car apart and used the veg as the car, no luck. What are we doing wrong? Is there any way to prove that electrical current is generated by the veg? I'm at my wits end with this (not a science person at all!)

Failing that, any impressive experiments that we can do in a short period of time where conclusions are made?

Thank you in advance!
Click to expand...

You need to be using two different types of metals. The dissimilar metals are the heart of the battery and the porato/lemon act as an electrolyte. Copper is the obvious choice for one end, but the other needs to be a metal that does not passivate - i.e. do not use a stainless steel nail, use an iron nail or zinc plated nail. A zinc/copper setup will work best. Be sure to stick the copper wire/ nail as deep as you can into the potato/lemon.

If you are lucky, you'll get maybe 0.6 V per potato/lemon. Two or three in series should be able to turn a very small motor.

EDIT: Make sure the electrodes are as close as you can get them together without touching under the outer layer of skin.
 
sumacveneneux said:
Thanks Sysem, we will get one over the weekend, BUT would still want to have success on the experiment. We can see that there is charge, as the potato goes black. Just not enough. It has been suggested that we soak the potato in lemon juice to increase the charge.

lcbxx - youtube lies! I'm sure of it. I think the guy put a battery in his potato. We've re-hashed the darn experiment so many times now, it's been 4 days of experimenting. :cry:
Click to expand...

I think you just answered your own question ..
 
Thank you so much for the advice, lcbxx and agentrfr! We're going to try it all. Maybe our copper wasn't enough...

lol @ evilstebunny, if it wasn't for term marks... :twisted:
 
I just wanted to let you know that my son, though he couldn't light a bulb, or drive a car with the lemons (they never tested over 1.4 v) , he did have success by showing current with the multi-meter. His teacher was quite impressed with his experimentation and effort, and so he gets an A+!

Thank you so much for your kind help, it's much appreciated!
 
Don't know what the instructions said, but I can guarantee that you would not be able to power a car as in make it move. Need some serious pimped potatoes for that. Lemon juice with a proper battery setup perhaps.
 
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