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Comparing the Electrical Output of
Various Electrolyte/Electrode Combinations in Wet-Cell Batteries |
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Researched by Kevin B.
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The purpose of this experiment was to compare the electrical potential of various electrolyte/electrode combinations in a wet-cell battery.
I became interested in this idea when my dad entered a school for H/VAC Technicians. He taught me how to use a voltmeter. After that I became more and more interested in batteries.
The information gained from this experiment could benefit battery producers. They need to know which electrolyte they should add to a wet-cell battery so that it will give the greatest electrical voltage.
My hypothesis was that the zinc and copper wet-cell battery would produce more electrical voltage.
I based my hypothesis on the fact that everyday batteries are made of a zinc-copper mix. This lead me to believe that producers use zinc and copper in the batteries that they produce because they have the best performance compared to other combinations.
The constants in this study were:
• Amount of electrolyte
• Size of test tube
• Size of zinc and copper strips
• Number of strips
• Size of wires
• Length of wires
• Voltmeter
The manipulated variable was the electrolyte and electrode combinations I was testing.
The responding variable was the electrical potential, in volts, of the different liquids I used.
To measure the responding variable, I used a voltmeter to find the amount of volts the battery produces.
| QUANTITY | ITEM DESCRIPTION |
| 2 | copper strip |
| 2 |
zinc strip |
| 2 | lead strip |
| 2 | porous cup |
| 2 |
250mLbeaker |
| 150 mL | Zinc Nitrate solution |
| 150 mL | Copper Nitrate solution |
| 150 mL | Lead Nitrate solution |
| 1 |
voltmeter |
| 1 |
pair of safety goggles |
| 1 |
apron |
| 1 |
pair of gloves |
| 1 sheet |
fine-grain sandpaper (220 grit) |
1. Put on rubber gloves, apron, and safety goggles.
2. Clean zinc, copper, and lead strips with fine-grade sandpaper to remove outside coating.
3. Place about 75mL of zinc nitrate solution in a 250mL beaker. Immerse clean zinc strip in solution.
4. Fill porous cup with about 2 cm of copper nitrate solution. Immerse clean copper strip in solution.
5. Connect one wire to the zinc metal and the other to the copper metal. Connect each wire to voltmeter.
6. Lift up and touch porous half-cell to the beaker’s solution to see if the battery is hooked up properly. The needle should deflect to the positive side of the meter. Switch the wires if the needle shows a negative deflection.
7. Place porous cup in beaker and immediately read meter. Record voltage in table.
8. Repeat for 10 trials.
9. Prepare lead half-cell in another beaker by pouring 75mL of lead nitrate solution in 250mL beaker. Clean copper strip thoroughly and rinse outside of porous cup with distilled water. Immerse copper cup in lead solution. Record voltage in notebook for 10 trials.
10. Change porous cups and set up zinc half-cell in porous cup by filling it 2cm with zinc nitrate solution. Place clean zinc strip in porous cup. Immerse zinc cell in lead nitrate solution. Repeat for 10 trials.
11. Clean-up area and wash materials with distilled water.
The original purpose of this experiment was to compare the electrical potential of various electrolyte/electrode combinations in a wet-cell battery.
The results of the experiment were that the lead-copper cell had the greatest electrical potential with an average of 483.6 mV. The zinc-copper cell had the least with an average of 93.8 mV. The lead-zinc cell was a high second with 421.1 mV.
See my table and graph
My hypothesis was that the zinc and copper wet-cell battery would produce more electrical voltage.
The results indicate that this hypothesis should be rejected, because the zinc-copper cell has the lowest voltage. The lead-copper cell performed the best.
Because of the results of this experiment, I wonder if the temperature of the electrolytes/electrodes would affect the voltage. I wonder if a more concentrated electrolyte would produce more electrical output. I also can’t help but wonder if the size of the electrodes would affect the voltage it produces.
My findings should be useful to battery producers because my results show that lead-copper produce more voltage than anything else I tested.
If I were to conduct this project again, I would use more combinations of electrolytes and electrodes. I would also conduct more trials for each combination to receive more reliable results.
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Introduction Batteries and other forms of electricity have been used for hundreds of years. They are an important part of our lifestyle and are used everyday by almost everyone in our society. Batteries A battery is a device that stores energy and makes it available in electrical form. They usually consist of electrochemical devices as one or more galvanic or fuel cells. Humans use batteries for countless purposes in their everyday life. We need batteries to power vehicles so that we can get from place to place. We use batteries to power many appliances that provide entertainment and meet other daily needs. Batteries power our CD players, radios, remote controls, cell phones, portable DVD players, and many other items. A battery has two terminals. There is a negative terminal and a positive terminal. If you connect a wire to each terminal, electrons will from the negative terminal towards the positive terminal. If you continue to do this though, your battery will short-circuit, which is potentially dangerous. You can gradually reduce the risk by adding a load to the circuit to take up some of that energy. There are two main ways to arrange batteries, in series or in parallel. A series arrangement adds voltage to the electric current, but the current stays the same. A parallel arrangement adds current, but the voltage stays the same. Battery Cells A battery is made up of three main parts, the two electrodes and the electrolyte. An electrolyte is a conductor in which electric current is carried by the movement of ions that are not metallic. Electrolytes can be a liquid or a paste, depending on the type of battery. Wet-cell batteries have a liquid and a dry-cell has a paste. Acids are used as electrolytes. One of the most powerful acids used in batteries is sulfuric acid, which is used in car batteries. Alkalies, such as baking soda, are used to neutralize acids. An electrode is a conductor used to make electrical contact with a part of an electrical circuit that is metallic. When two electrodes are placed into an electrolyte and a circuit with a load is completed, electrical current flows out of the negative terminal, and into the positive terminal. Chemical Reactions When a circuit is connected to the battery, chemical reactions strip the electrons from the atoms in the electrolyte, gather in the negative terminal, and send them through the circuit. Chemical reactions that produce electrons are called electrochemical reactions. If there is a circuit, the electrons enter back into the battery through the positive terminal. When you add a load to the circuit, like a light bulb for example, it will use some of the electricity in the circuit to power up. In the case of the light bulb, it will light up. Kinds of Batteries There are many types of batteries that we use everyday. Zinc-carbon batteries are used in making standard AA, D, AAA, and C-cell batteries. Alkaline batteries are basic everyday Duracell and Energizer batteries. Lead-acid batteries are found in most automobiles. The combination of lead and acid creates a strong acidic battery. Lithium-ion batteries are used in laptop computers and cell phones for their long-lasting design. Zinc-mercury oxide batteries are used in hearing aids because of their compact design. Electricity Electricity is the collection of physical effects resulting from the existence of charged particles, especially electrons and protons, and their interactions. This means that electrons are bouncing from atom to atom and are sometimes traveling through a conductor. Electricity is used everyday by people all around the world. In homes people use electricity for appliances such as dishwashers, toasters and vacuum cleaners. Microwaves and food processors help us prepare food quickly and easily. Refrigerators and freezers help preserve food. Air conditioners and fans help cool homes while electric heaters provide warmth. TV’s, radios, video games, and CD players provide entertainment. Electricity is used industrially use in factories’ conveyer belts and assembly lines. Manufacturers use electricity to make sure a product’s size is correct. Electricity powers drills, saws, elevators, and cranes to make homes. Electricity is mainly used in industry for welding and smelting. Smelting factories are placed near electrical plants because they take up an enormous amount of electricity to run the smelting machinery. Electricity is used in everyday communication. Telephones, TV, radio, fax, and computers all run on electricity. Satellites use electricity to send signals everywhere around the world. Without electricity, subways, trains, and trolleys wouldn’t work. Cars use electricity to start and stay running. Electric vehicles exclusively use electricity to work. All airplanes and ships are electrically powered. Electricity is used in the fields of science and medicine. Health workers use electricity to run operational instruments. Scientists use scanning electron microscopes to learn the secrets of living cells. Some telescopes that astronomers use run on electricity. Conductors/Insulators Conductors are materials that an electric charge moves easily through. Materials that conduct electricity contain charged particles that are free to move throughout the material. If an electric charge is applied to the conductor, the charged particles will loosen and spread over the materials surface. Most conductors’ free particles are free electrons that aren’t attached to atoms. Some conductors’ free particles are ions. Metals make good conductors because they have a large number of free electrons. Most wires made to carry electricity are metal, mainly copper. Liquids also make good conductors. Salt water contains sodium and chloride ions that are free to move about. Even gases make good conductors. When gases get extremely hot, the atoms move so fast that they collide and the electrons pull free. This is called plasma, which also exists on stars, like the sun. Superconductors are a special type of conductor. A superconductor allows electrons to move freely without losing energy. Superconductors only work at very cold temperatures, though. In insulators, the electrons are tightly bound to the atoms and are not free to move about. If an electric charge is applied to an insulator, the charge won’t move through the material. It will just stay in place. Glass, rubber, dry air, dry wood, and plastic all make good insulators. Insulators are an important part of electrical safety. They make wires safe to touch, even when plugged into an outlet. Electrical Measurements There are many types of electrical measurements. One type is voltage. Voltage is the electrical charge between two points. The word “voltage” comes from the inventor Alessandro Volta, who invented the first battery. The more volts a battery has, the stronger the push of electrical flow. A watt is the power of the electric current, named after James Watt. One kilowatt=1000 watts. An ampere is the rate of flow in an electric current, named after Andre Marie Ampere. 1 ampere=6 billion electrons flowing past one point in one second. Atoms All matter in the universe is made up of two kinds of tiny particles; electrons and quarks. Electrons and quarks have a property called electric charge. Protons and neutrons make up the quarks. Electrons have a negative charge and quarks have a positive charge. Opposite charges attract while like charges repel. The power to do this comes from electric fields that surround each charged particle. When quarks and electrons combine, they form atoms. Inside the atom, the protons and neutrons join to form the center of the atom, or nucleus. The positively charged nucleus attracts electrons, which swirl around the atom. An ion is an atom that carries an electric charge, usually positive. Summary Batteries and electricity are both huge leaps in the scientific world. We will continue to invent more forms of energy in years to come. |
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“AC-DC Inside the Battery.” PBS. October 15, 2004 http://www.pbs.org/wgbh/amex/edison/sfeature/acdc_insidebattery.html “Acids and Alkalies.” Young Scientist. 1997 “Batteries.” Electrical Current. January 12, 2005 http://en.wikipedia.org/wiki/Battery_(electricity) Brian, Marshall. “How Batteries Work.” How Stuff Works. October 22, 2004 http://science.howstuffworks.com/battery1.htm “Electric Current.” Electric Charges. January 11, 2005 http://www.amasci.com/miscon/curstat.html “Electricity.” Electric Current. January 12, 2005 http://en.wikipedia.org/wiki/Battery_(electricity) “Electricity and Magnetism.” Electrical Charges. January 11, 2005 http://www.sciencemadesimple.com/ “Electricity.” Voltage and Electricity. January 11, 2005 http://www.amasci.com/miscon/curstat.html Heimler H, Charles and Price, Jack. Focus on Physical Science. Colombus: Merrill, 1987. P.p. 303-309, 311, 312, 314-316, 318, 319 “Voltage and Magnetism.” Voltage and Electricity. January 11, 2005 http://www.sciencemadesimple.com/ Wolfson, Richard. “Electricity.” The World Book Encyclopedia. 1998 |
I would like to thank the following people for helping make my project possible:
• My parents for assisting me with the experiment and for giving me the courage to succeed in my project.
• Mr. Newkirk for setting up after school classes so that I could finish my experiment and report on time.
• Mrs. Helms for encouraging me to do my best.
• Mr. Ketcham for helping me conduct my experiment.
• Nathaniel for giving me tips on how to do my experiment.
• Ethan for showing me how to create my graphs.
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