# Making Cents with Batteries

## Introduction

A battery is chemical energy that creates electricity by how some chemicals are able to come in contact with each other in specific ways. There are three parts that make up a battery. The first part being the anode. The anode is generally a positively charged electrode, which mainly attracts negatively charged electrons. In this specific part of the battery is also where oxidation (loss of electrons on the surface of atoms or ions is oxidation) occurs. The opposite of the anode is the cathode. The cathode is normally the negatively charged electrode, that attracts positive charges. In the cathode is where reduction (gain of electrons that were previously lost) also occurs. The anode and the cathode work side by side in the battery, just like oxidation and reduction. Chemical reactions in the battery build up the electrons in the anode. The only place these electron can go is to the cathode. The electrons in the battery want to move from the anode to the cathode. They are stopped from going within the battery from the anode to the cathode by the electrolyte. The electrolyte is found in the center of the battery, and they create a wall between the anode and cathode. when the circuit is closed, a wire or conductor connects both ends of the batter to each other, the electrons are able to flow from the anode to the cathode. Causing electricity to be made within the battery, which the battery can now supply the electricity where it is needed. A battery will continue to produce energy until one or both of the electrodes don't have anymore of the substance that is required for the battery to keep the reaction constant and produce electricity.

## Purpose, Problem, and Hypothesis

Purpose:

The purpose of this experiment was to experiment with different coin combinations and a salt/vinegar solution and see which combination creates the highest voltage.

Problem:

What combination of coins would create the highest voltage?

Combinations tested:

• Pennies and nickels
• pennies and dimes
• Pennies and quarters
• Nickels and dimes
• Nickels and quarters
• Dimes and quarters

Hypothesis:

If the voltaic pile of pennies and dimes has all the metals needed to create electricity, thence voltaic pile will create an ample of an electric current.

## Materials

• vinegar- 1 cup

• salt- 1 tbsp.

• 1 small bowl

• 4 pennies

• 4 nickles

• 4 dimes

• 4 quarters

• dish soap- any kind

• one 2 cm by 8 cm strip of aluminum foil

• a pair of scissors

• paper towels

• a plate (not paper or metal)

• digital multimeter- with probes (reads mA and mV)

• notebook for data

• pencil/ pen

## Procedure

First the first step is to make sure that the aluminum strips are cut into 2cm by 8cm strips and the paper towels squares are cut big enough to cover the coin. Make the salt/vinegar solution by pouring the designated amounts of each into a bowls and stirring for about a minute. Make sure that all the coins are washed, dried, and ready to begin the experiment. Now begin to make the first coin combination pile (start with any combination desired). Place a strip of aluminum foil on a plate and place the first coin on one end of the fool strip. Now soak a paper towel square with the solution and squeeze out the extra liquid in the paper towel. Then place the paper towel on the coin already placed on the foil strip. Place the other coin in the combination on top of the solution soaked paper towel. Continue this process until all the coins that are needed for the combination are stacked. Now set the multimeter to measure millivolts and place on probe tip on the fool strip and on probe tip on the top coin in the stack. The specific color probe that goes on the coin and the strip will vary according to the model of the multimeter. Write down the first number that is seen on the multimeter screen. Continue this process for every test.

## Variables

• Independent Variable:

• coin combinations

• Dependent Variable:

• the voltage

• Experimental Group:

• testing different coin combinations with vinegar

• Constants:

• the multimeter used

• the location where the experiment is conducted

## Statistical Analysis

This experiment compares the voltage that a coin combination creates. Six different coin combinations were tested. Each test and trial resulted with a different voltage created. For one coin combination, if compared, each of the nine tests had different voltages that were created, but they were mostly very similar. One coin combination, nickels and quarters, had very similar voltage outcomes all of the nine times the voltaic pile of the two coins were tested. The voltage of the voltaic pile of nickels and quarters only had two results that would reappear almost every other time, 0.01 and 0.02. The average of this voltaic pile is 0.016. The is combination created the least amount of millivolts out of all the piles that were tested. The voltaic pile that created the most millivolts was the combination of pennies and nickels. The millivolts created through the nine tests ranges from 0.71 to 1.52 millivolts, and the average of this voltaic pile is 1.19. This voltaic pile was followed by the voltaic pile of pennies and dimes with the mean of 0.93; the mean of pennies and quarters -0.90- followed closely behind the pile of pennies and dimes. The difference between the mean of the pile of pennies and quarters and the pile of nickels and dimes was huge; the mean of nickels and dimes being 0.30. The pile of nickels and dimes followed by the pile of dimes and quarters with the mean of 0.26 and finally followed by the pile of nickels and quarters with the mean of 0.02.

## Conclusion

Specific coin combinations have the same amount of specific metals found in batteries. The voltaic pile of the coin combination of pennies and dimes was the combination thought to create the highest voltage out of all six coin combinations that were tested. The voltaic pile of pennies and dimes created the second most millivolts after the combination of pennies and nickels. The most millivolts that the combination of pennies and nickels was 1.52 millivolts while the highest voltage of the combination of pennies and dimes was 1.12 millivolts. The next coin combination that created the most voltage was the combination of pennies and nickels with the highest voltages created being 0.94 millivolts. The similarity between these three combinations is that all three include pennies. Pennies have almost half the metal needed to create a voltage. Nickels, dimes, and quarters have the same metals in them, but the only aspect that is not the same is that the percent of the metals is different because the size of all three coins is not the same and the metal zinc found in pennies is never present in any of these three coins. Out of all three combinations the amount of metals and the size of the nickel is the best coin to create a high voltage. Dimes are smaller than nickels and quarters but they are closer to the right amount metals than quarters. The coin combination of nickels and quarters only created two voltages throughout all nine tests, 0.01 and 0.02, which were also the lowest voltages created out of all the combinations tested. The same percent of metals (copper and nickel) are found in dimes and quarters, so when they are paired up together to find the voltage they do not have zinc at all. This results with a higher voltage in the combination of dimes and quarters than in the combination of quarters and nickels, because nickels are split evenly between the metals copper and nickel meaning that both metals are 50% each in nickels. The combination of pennies and nickels is the best combination out of all the combinations tested to create the most voltage in millivolts because the metal zinc is only found in pennies and that metal is needed to to create a strong voltage as well as the metals copper and nickel that are found in nickels, dimes, and quarters, but the amount of each metal found in nickels is the best amount found out of all the three silver coins.

## Sources of Error

Errors that could have possibly been made during the actual experiment could be that during the process of making the vinegar/ salt solution, too much or too little of either material could have been poured into the bowl. Along with these two materials, when dipping the small paper towel squares into the solution and squeezing out the excess solution, all of the excess solution may not have been squeezed out.

Another error that could have occurred at any point during the experiment could be that the paper towels could have been cut out too large or too small to cover the coins being tested. This could cause the paper towels to either be touching each other while they are a part of the voltaic pile or they could have been too small and would not have had enough of the vinegar/ salt solution.

## Expanding the Experiment

To expand or improve on to this experiment, different ways could be to actually test international coins that have different amounts of different metals in them and see the voltage created. Experimenting with the vinegar/ salt solution could also be a future experiment where different liquid solutions could be tested to find the most effect one.

## Real World Application

The piles of different coin combinations represent batteries. All batteries are stacks of metal and an electric liquid that were recreated through stacks of coins and a vinegar/ salt solution. Batteries are used everywhere by everyone on a daily bases. Experimenting with different metals that make up the batteries could be beneficial because some other metal combinations might create a higher voltage that the combinations that exist today.

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## Acknowledgements

A special thanks to the parents of Anusha Mittal who helped her get and pay for the materials she needs to perform the experiment. Another person greatly responsible for this whole experiment is Mrs. McDowell who was always one step ahead of all of her students and made sure that all experiments were being completed on time. She set up due dates and checkpoints for specific portions of the whole experiment to keep the projects on a steady pace to completion and absolute success. Students were giving class days to work on science fair projects and provided extra information to make sure the final products were better that just “good”. Mrs. McDowell was a true leader and teacher throughout the whole semester that this project was worked one.

Thank you.