|WikiProject Chemistry||(Rated C-class, Low-importance)|
- 1 Name
- 2 File
- 3 Update
- 4 Aluminum-Copper battery?
- 5 Where do you get the zinc strips?
- 6 Chemistry Problems
- 7 personal external links
- 8 lemons limes and grapefruit OH MY!
- 9 The voltage of this battery is higher than an Zn/Cu electrochemical battery
- 10 Vandalism
- 11 Calculations
- 12 A good title for a very Good Idea
file" link on the left hand pane of the page.If you name the file Lemon_battery.png the new file will simply replace the old one and you wont have to do anything else apart from refreshing your browser to see the effect. Please add something about the copyrite status in the comment box, i.e. you drew the diagram yourself. Or the diagram was drawn by name: who gave you permission to put it on wikipedia.
See these two pages for more details.
Having said that, there have been a few problems with hardware over the past few days and image uploads have had to be disabled from time to time (see the Village pump for discussion) so if you have any trouble try again in a couple of days.Thanks theresa knott 09:52, 7 Jan 2004 (UTC)
- I've provided a link to a page with images of the four-lemons-and-an-LED version. Melchoir 20:58, 20 January 2006 (UTC)
!!! REAL WORLD UPDATE FROM AN ORDINARY HUMAN !!! 01/24/2007
Hello, I am NOT a science professor, merely a frustrated Floridian father of a Fifth Grade boy. This means I need to guide my son through an annual ritual known as the "Science Fair Project." This year my son came upon the lemon battery, and thought that looked like a ballyhoo of a good time. He started combing the web looking for information. I was impressed by two things: the amount of websites he took the time to visit and study, and the generally useless content he found. To clarify:
MATERIALS, and where to get them: Many web pages STILL suggest a "trip to your local hardware store" for "strips" of Zinc and Copper. REALITY: In the modern day of Home Depot and Loews stores within a mile of each other, "local" hardware stores are as scarce as hen's teeth. Sadly, Home Depot does NOT stock strips of Zinc and Copper (neither does your local Radio Shack, for that matter). ALTERNATIVE: Thankfully, a couple of web pages mentioned substituting a Galvanized Nail for the Zinc Strip. I was assured by many sources that galvanized nails are, in fact, steel nails that have been coated with zinc. A trip to Home Depot's Plumbing Department yielded a cylindrical copper pipe fitting, about 3/4 inches in diameter and 1 inch long. Finally, the Electrical department had a multimeter (many websites still datedly call for a "voltmeter") with positive and negative probes. A trip to our corner supermarket yielded three (3) each of apples, lemons and potatoes. TOTAL Materials Cost: Around $20.00 US (January 2007).
PROCEDURE, and the pulling of many hairs: Not nearly enough websites indicate the best placement of your zinc and copper "electrodes," though a few suggested spacing them about 1 inch apart. Even FEWER websites indicated that the Positive Probe of the multimeter should be placed on the copper, and the Negative Probe on the zinc. Please realize that there are likely many "ordinary" folks like myself who try this experiment, who do NOT fully understand the electrochemistry, and absolutely need this level of detail! Finally, we did not find a single website that indicated what "Range" setting to set the multimeter to in order to get a reading. This omission alone should be considered criminal. There are 14 possible settings within 5 labeled groups on our multimeter. We wound up testing ALL 14…
INITIAL RESULTS: NO reading on the multimeter whatsoever. We moved the probes slowly up and down the nail, and all around the copper fitting. We tried waiting -- 15 minutes, 30 minutes, 1 hour -- in case it took time for the chemical reaction to "generate" a result. ZIP. NADA. ZILCH. Back to the web. More research yielded a few sites that scrapped the zinc and copper strips for an ordinary STEEL PAPERCLIP, and a copper Lincoln PENNY (being downright suspicious of everything we found at this point, and realizing that "modern" copper pennies have less and less actual copper in them, we made sure to dig up a penny from 1961.) With our trusty paperclip and 1961 penny inserted approximately 1 inch apart, we began probing with our multimeter again…
FINAL RESULTS (???): Here's the part I would love to have explained to me in LAYMAN'S terms: The ONLY readings we were able to generate were on the "10" ACV scale, and on the OHM scale. My limited knowledge of electricity leads me be believe that the OHMs reading is a measure of resistance, or how difficult a time the electrons are having traveling around their circuitous route. So we ignored the OHM reading. A great book titled "Tesla: Master of Lightning" makes it pretty clear that Nikola Tesla deserves far more credit as an electrical visionary, and Edison a lot less. Among many such discoveries, Tesla was the pioneer of Alternating Current (AC), without which our modern society would be much the poorer. Well, our lemon generated 8 volts AC, which as far as I can tell, means the electrons were REVERSING direction – perhaps 60 times a second! By the way, the apple measured 7 volts AC, and the potato 5 volts AC. These results were consistent and repeatable. I can e-mail you a photo of our probes touching the lemon electrodes and the gauge face of the multimeter (firstname.lastname@example.org). **** NO WAY THE VEGETABLES WERE PRODUCING AC, AND VOLTAGES LISTED ARE UNREAL. SHOULD BE A BIT LESS THAN 1 VOLT ****
Here is the result of another experiment, by someone else, done just today. I went to a hardware store and bought 4 large (about 1.5 inch dia.) hot dip galvanized steel washers to use as the zinc components. I cut 4 slightly smaller circles of copper from a small sheet I bought at the same store. I cut 4 even slightly smaller circles of pulpy paper from the top of an egg carton. I soaked the paper in some white vinegar that had a lot of table salt dissolved in it. I assembled 4 cells, alternating washer, paper, copper, and stacked them together into a battery, being careful not to let the paper short circuit the cells. I placed some pieces of cedar shim on the top and bottom of the stack and clamped the whole assembly together tightly. I tested the battery with a yellow LED in series with a 66 ohm resistor. Three cells produced enough voltage to light the LED, however it was much brighter using the full 4 cells. (A red LED might light with only two cells, a white LED might require 5 cells.) The battery effectiveness increased dramatically after it had been assembled for a few hours (perhaps some excess liquid had been providing a leakage path and the battery worked better when this dried out). Using a multimeter set on the 9.99 volts DC max scale, and with nothing else connected to the battery (that is, when measuring the "open circuit" battery voltage), the meter reads about 2.8 volts, or about 0.7 volts per cell. It is not a very good battery; I measure a short circuit current of about 6 milliamperes. Therefore the equivalent series resistance of the battery is close to 500 ohms. I do not need the external 66 ohm resistor to protect the LED from overcurrent! (A common LED can handle 30 milliamperes, this battery can only deliver 6 at best.) Using all 4 cells, the LED voltage measures about 1.85 volts, and the 66 ohm series resistor voltage measures about .045 volts; the calculated current is about 0.6 milliamperes. This measurement gives an equivalent series resistance of the battery about 3 times higher ((2.8V-1.8V) or about 1 Volt/.0006 Amperes), around 1500 ohms. Really not a very good battery! Still, it was good enough to spark the electrical revolution! AJim (talk) 05:38, 25 November 2011 (UTC)
Could somebody calculate how much kW-h/kg could give us aluminum-copper galvanic pair?Is such reaction reversible?
Where do you get the zinc strips?
You know, when I was a kid, you could still find zinc pennies that were actually made of zinc. At least I think they were (probably an alloy). I made Voltaic cells out of copper pennies, zinc pennies, and wads of paper towel soaked in salt water.
But these days, where do you find zinc? If you're going to go to a hardware store to buy zinc, why not just pick up an alkaline cell?
Wouldn't it be more practical to suggest aluminum?
As a kid I always suffered from home science project books that used materials that no doubt were once easy to come by, but no longer were. All those static electricity experiments with sticks of sealing-wax and gutta percha... and "photographer's collodian..."
I wonder whether you can still buy Rochelle salts at a drugstore? I once tried to grow my own piezoelectric crystals—they didn't work, I don't know why—and I remember the druggist giving me a slightly funny look since I bought a pound of the stuff and the only pharmaceutical use for it was as a laxative. Dpbsmith (talk) 19:12, 7 Jun 2005 (UTC) by now i found some at staples —Preceding unsigned comment added by 126.96.36.199 (talk) 00:31, 2 November 2010 (UTC)
Here are two ways to get zinc: galvanized hardware and zinc electrodes for boats. Zinc is widely used to protect iron and other metals from electrolytic corrosion. Hardware stores or hardware departments in places like Home Depot do have galvanized hardware. You can find, for instance, nails and washers that are galvanized by being dipped in molten zinc ("hot dipped"); they have a pretty thick zinc coating over the iron and can be used as "zinc strips". Also, marine supply stores sell zinc in various cast forms for attaching to propeller shafts and other objects that would otherwise be subject to corrosion. If you are near such a supplier you will find they have plenty of zinc. A piece of such zinc is soft and fairly easy to cut with a saw into strips. AJim (talk) 04:28, 25 November 2011 (UTC)
The way it is written now, it seems that a reduction and an oxidation reaction occur at the anode. However, I learned that reduction occurs at the cathode and oxidation occurs at the anode. Unless anyone has a reason for this, I will change it.
It seems that my editing has been negated. Why? How can reduction and oxidation occur at the anode?
I just noticed that User:Msdaif is (presumably) the owner and originator of the content to which he has posting external links. This is generally frowned on (see WP:EL and WP:COI). Is some other editor really thinks we ought to have those links, they can add them. I'm going to take them out for now. Dicklyon 21:04, 3 September 2007 (UTC)
lemons limes and grapefruit OH MY!
The voltage of this battery is higher than an Zn/Cu electrochemical battery
A lemon battery with copper and zinc strips, or a modern copper plated cent and a galvanized nail, stuck in a lemon, can produce 0.9 volts or so, but the current is too low (a few milliamps) to operate a flashlight bulb. A type 131 bulb is still available from many hardware stores, for about $1.55,or as little as $.45, as is the miniature socket it screws into. Zinc and [ 93293 COPPER STRIP copper strips] are sold by American Science Center. Lots of electrical science kits and materials are still sold by Edmund Scientifics. The little type 131 flashlight bulb is rated at 0.1 amps and 1.3 volts. Most flashlight bulbs are rated at more amps and more current. To get adequate voltage, place two lemon batteries in series (zinc of one battery to copper of the other, and the remaining zinc and copper electrodes are the output terminals0. To get adequate current, connect your battery across a capacitor. Radio Shack has Model 272-1022 capacitor, electrolytic, 4700 microfarad, 35 volt. Connect it with the positive lead to copper and the negative lead to zinc. The other way will destroy the capacitor.
Get a momentary switch or a knife switch and hook the light bulb and switch across the capacitor.Leave the bulb switch open while the cap[acitor charges from the lemon battery. You can connect a voltmeter across the capacitor to monitor the voltage . When it appear close to 1.5 volts, close the switch and the stored electricity will momentarily flash the lightbulb. A small capacitor will not store enough electricity to make the bulb light, and the trickle of electricity cannot light the bulb by itself. Two series combinations of two lemon batteries, themselves connected in parallel, might produce enough current and voltage to light a small LED (light emitting diode). Determine the positive and negative terminals of the LED and connect the negative (cathode) to the zinc and the positive (anode) to the copper. No capacitor should be necessary. Edison (talk) 00:22, 21 February 2009 (UTC)
The section on calculations is wrong. The voltage is governed by the difference in potential between the two metals. The current is dependent on the voltage and the circuit resistance. (0.00015 A is quoted - from where?) This depends on the acidity of the lemon and the type and size of electrode. I can't think how it could be revised it to make sense without making it overly complicated, so I'm removing it. Apau98 (talk) 11:25, 21 January 2011 (UTC)
- The updated calculations still seem a little dubious to me. If using copper and zinc, the difference in potential is around 900 mV, so fair enough, but where does the current value come from? I'll revise the article so the assumptions are explicit. I've done some rough calculations and I think the correct current value could be higher than that, but so much depends on the size of the electrodes and the acidity of the lemon, that there are too many assumptions for it to be worthwhile including them. Apau98 (talk) 06:13, 22 January 2011 (UTC)
- This section appears to be original research. The key issue is the figure of 0.3 mA for the battery's current, which is unreferenced and crucial to the section's illustrations. I'll delete the section shortly if a reference isn't added. I have done a quick search and did not find anything published to back up this figure. Easchiff (talk) 04:33, 3 October 2012 (UTC)