/-/https/www.sciencebuddies.org/cdn/Files/21464/5/sb-logo.png){kind=logo}
/-/https/www.sciencebuddies.org/cdn/Files/21464/5/sb-logo.png){kind=logo}
Hi,
I made a penny nickel battery but when I stack the cells, the battery doesn't produce a charge anywhere near the additive total of each individualcell. Does anyone have an explanation for this? Thanks
penny nickel battery questions
Moderators: AmyCowen, kgudger, bfinio, MadelineB, Moderators
-
krm
- Posts: 1
- Joined: Mon Feb 16, 2015 6:24 pm
- Occupation: Parent
- Project Question: We made a nickel penny battery. It says the voltages should be additive when you stack the cells, but ours was not. When we stacked 10 cells on top of each other, the voltage only reached 2.38 V. Adding each of the 10 cells separately, we should have gotten 4.32 V. How do we explain this?
- Project Due Date: 2/18/15
- Project Status: I am finished with my experiment and analyzing the data
-
deleted-249560
- Posts: 496
- Joined: Thu Nov 20, 2014 1:35 pm
- Occupation: Science Buddies content developer
- Project Question: N/A
- Project Due Date: N/A
- Project Status: Not applicable
Re: penny nickel battery questions
Three things to watch for when you make your coin battery:
1) The coins need to be clean. Oxidation or dirt will interfere with the current flow
2) Each element is a nickel, a penny and a piece of wet paper. When you stack these elements together the penny from one element rests directly on the nickel of the one below. Do not put paper between those two coins. You will use the same number of paper squares as you used pennies or nickels.
3) The paper squares can't touch each other. They should be big enough to fully (or mostly) cover the coin but small enough that the corners don't bend down and touch anything else. You can cut circles instead if you think that could be a problem.
Howard
1) The coins need to be clean. Oxidation or dirt will interfere with the current flow
2) Each element is a nickel, a penny and a piece of wet paper. When you stack these elements together the penny from one element rests directly on the nickel of the one below. Do not put paper between those two coins. You will use the same number of paper squares as you used pennies or nickels.
3) The paper squares can't touch each other. They should be big enough to fully (or mostly) cover the coin but small enough that the corners don't bend down and touch anything else. You can cut circles instead if you think that could be a problem.
Howard
-
docbill
- Posts: 2
- Joined: Sun Jul 05, 2015 7:50 am
- Occupation: computer scientist
- Project Question: commenting on nickel penny batteries
- Project Due Date: N/A
- Project Status: Not applicable
Re: penny nickel battery questions
Like many children, I did the copper penny experiment, and it worked great. However, you have to realize this is a very old experiment. The composition of pennies has completely changed. Prior to 1982 pennies where 97.5% copper, 2.5% zinc. After 1982 pennies where 97.5% zinc, 2.5% copper. In fact it is possible to create a battery using only pennies, half dated before 1982, and half after 1982. Avoid 1982 pennies in your experiments as that was the year other combinations where experimented with...
The nickel has remained pretty much the same. 25% nickel, 75% copper... So try your experiment both with pennies all from before 1982, and with pennies all after 1982.
Now the next thing to note, is when stacking your penny batteries, make you are completely dry between the penny stacks. Lets say you did the extreme opposite. Lets say you stacked a nickel, wet paper towel, penny, wet paper towel, nickel. If you look at this you actually have two batteries stacked in opposite directions. As such you would measure zero voltage between the nickel. When you then stack at either end another wet paper towel and a nickel, you'll have two batteries in one direction, and one in the opposite, making one net battery. If for example you use water to clean the surfaces before stacking, you are cancelling out most of the effect of stacking. Ideally it would be best to use some neutral metal between the batteries, as you'll always have some moister which will always cancel out part of the effectiveness of stacking. That is one reason why when you buy commercial batteries you don't actually have the metal used for the batteries exposed.
Of course using some alcohol to clean will help. But if so, use the 99% alcohol, not the 50% or 70% you'll find on sale at Walmart. Pure rubbing alcohol won't conduct or serve to make a battery and it will evaporate very quickly.
The nickel has remained pretty much the same. 25% nickel, 75% copper... So try your experiment both with pennies all from before 1982, and with pennies all after 1982.
Now the next thing to note, is when stacking your penny batteries, make you are completely dry between the penny stacks. Lets say you did the extreme opposite. Lets say you stacked a nickel, wet paper towel, penny, wet paper towel, nickel. If you look at this you actually have two batteries stacked in opposite directions. As such you would measure zero voltage between the nickel. When you then stack at either end another wet paper towel and a nickel, you'll have two batteries in one direction, and one in the opposite, making one net battery. If for example you use water to clean the surfaces before stacking, you are cancelling out most of the effect of stacking. Ideally it would be best to use some neutral metal between the batteries, as you'll always have some moister which will always cancel out part of the effectiveness of stacking. That is one reason why when you buy commercial batteries you don't actually have the metal used for the batteries exposed.
Of course using some alcohol to clean will help. But if so, use the 99% alcohol, not the 50% or 70% you'll find on sale at Walmart. Pure rubbing alcohol won't conduct or serve to make a battery and it will evaporate very quickly.