Hey guys,
My 10 year old has chosen me to help hgim with his science fair project. He wants to use fruit as batteries to power a clock, or an LED. His hypothesis is that citrus fruits like lemons will make th ebest battery. I have no idea. I'm not sure if we can even get a clock to work from a fruit or potato, but we'll see. I was thinking a steel nail, or piece of lead and a piece of copper should work with the fruit. Any suggestions as to how to carry out these experiments? How much voltage can one expect out of a fruit battery? Will one run a clock that runs on one AA battery usually, or will we need multiple fruit wired in series? My guess is no matter which fruit we use a clock is out of the question, but maybe I'm wrong.
Thanks,
Chris
I would look at other fruit than lemons. Why? Lemon batteries have been around for a long time.
https://en.wikipedia.org/wiki/Lemon_battery
Perhaps experiment with a series of fruit to see which one is best, and hypothesize why.
I'm wondering if we could get an analog clock to power with these batteries. Therefore we can set them to a certain time to start, and then see how long the battery powers them. With the digital clock we can't see that short of watching the clock, or filming it to see how long it lasts. I don't want to watch a clock, and I don't have any idea how long it will last anyway, so filming it may take a long time.
I used to have a potato-powered clock when I was a kid. It was similar to this:
I think it worked for about two weeks. I wanted to keep it going but my mom ketp telling me not to waste potatoes. 
If Macgyver can do it, so can you!
trucke wrote:
If Macgyver can do it, so can you!
I used to have hair like that as well. True story. My boys found an old picture of me with a mullet, and created a Pokemon card of it. It was called Mullet Man EX.
The metals you want to use are copper and zinc for the best results. The voltage expected from lemons is in the 2.5 to 3 volt range. You could try different fruits as mentioned to see if there is a connection to the acidity levels. The how long will a clock run on different fruits is a good idea. Simple and easy to document in at lest 12 hours steps.
NEALSMO
UltraDork
1/17/17 2:19 p.m.
Put it in a briefcase and you may get an invite to the White House, although you might have to make a pitstop at your local jailhouse first.
Mazdax605 wrote:
My 10 year old has chosen me to help hgim with his science fair project. He wants to use fruit as batteries to power a clock, or an LED. His hypothesis is that citrus fruits like lemons will make th ebest battery. I have no idea. I'm not sure if we can even get a clock to work from a fruit or potato, but we'll see. I was thinking a steel nail, or piece of lead and a piece of copper should work with the fruit. Any suggestions as to how to carry out these experiments? How much voltage can one expect out of a fruit battery? Will one run a clock that runs on one AA battery usually, or will we need multiple fruit wired in series? My guess is no matter which fruit we use a clock is out of the question, but maybe I'm wrong.
I used to teach 4-8th grade science. The science fair was a BIG deal for our school (our little Montessori school with a single class of 28 middle schoolers one year took home the most awards from the California State Science Fair). So I can weigh in on these things.
The big thing is that a science fair project is about the process, not the result. He should be asking questions. He should try to do things and have them not come out right. You should just be a resource to suggest ideas he might not think of and to procure the supplies. It is entirely fine if he starts out trying to figure out one thing (which fruit or vegetable works best?), and ends up figuring something else out entirely (what is a circuit? what is the difference between series and parallel? which one works best for this? what are an anode and a cathode?)
All these things you are asking are things your son should try to determine in the course of the experiment:
What type of metals do you need for anode and cathode? - Dunno. Try a couple and see if one works better than the other.
How much voltage can one fruit battery generate? - Try it and see.
If I need multiple fruit batteries, should they be wired in series or in parallel? - Try both and see.
Your should really just help by teaching him how to use the voltmeter or multimeter and how to use it to measure voltage and amperage. Let him take the readings. Look over his shoulder to remind him to record everything that he does. Including recording things he tried that ended up not working. Let him figure out that one fruit battery isn't enough and that he'll probably need at least two. Introduce the idea of series and parallel and let him figure out which works best.
You should also use a control group of a clock powered by a standard battery (AA, probably).
If, in the end, he is not able to produce enough electricity to power a small clock or light bulb, that's fine. That is a legitimate scientific result. As long as he can explain why it did not work.
Great post Beer Baron.
I’ve got two daughters (nine and twelve) and I have yet to see anyone perform a proper statistical analysis on their hypothesis (i.e. what is the likelihood that the observed difference in means between groups can be attributed to the independent variables…in your case, the I.V.’s would be different metals, fruits, etc. as opposed to variation coming from measurement error, lack of sample homogeneity, etc..
I’d be happy to crunch the numbers and provide an age appropriate explanation along with cool scientificie looking graphs that your kid could present…just PM me if you’re interested.
In reply to RX Reven':
That's a big thing that formed the core of our curriculum and that I still rant to get people to understand: Science is not a body of knowledge. Science is a method; a process. It is a guideline for being able to find and evaluate claims. A science fair project is a way for students to demonstrate their understanding of the scientific method.
Also, most of science is, "Nope. That didn't work."
Beer Baron wrote:
Also, most of science is, "Nope. That didn't work."
So what you're saying is my dating life is science?
minivan_racer wrote:
Beer Baron wrote:
Also, most of science is, "Nope. That didn't work."
So what you're saying is my dating life is science?
Only if you are recording the results.
Beer Baron wrote:
minivan_racer wrote:
Beer Baron wrote:
Also, most of science is, "Nope. That didn't work."
So what you're saying is my dating life is science?
Only if you are recording the results.
Pretty sure you have to get the other party to sign a waiver if you want to make those "recordings".
