How does the acid content of different fruits and vegetables (apples, potatoes, limes and lemons) affect the electricity (volts) produced as read with a voltmeter?
The first battery was created in 1799 by Alessandro Volta. Today batteries provide the power for an amazing variety of devices including everything from flashlights to robots, computers, satellites and cars. Inventors and researchers continue to improve the battery, designing batteries that last longer and that are friendlier to our environment.
I chose this topic because I have an interest in making batteries out of things we use every day, such as fruit and vegetables.
Batteries generate electricity through a chemical reaction between two different electrodes and one electrolyte. An electrode is a conductor through which electricity enters or leaves an object, substance, or region and an electrolyte is a liquid or gel that contains ions and can be decomposed by electrolysis.
A battery produces an electric current when its terminals are connected to each other to form a circuit. All batteries contain two electrodes and an electrolyte, which produces the chemical reaction through the electrodes resulting in a current. In "dry" batteries, like those used to power small toys (AA, AAA batteries for example) the electrolyte is a paste of powdered chemicals. "Wet" batteries, like those in cars, contain a liquid electrolyte. A battery’s voltage depends on the metals that are used in its electrodes.
In a standard battery, there is a strong metal case which usually consists of powdered zinc and a form of magnesium oxide, both mixed with an alkaline electrolyte. The electrolyte causes a chemical reaction in which the zinc becomes zinc oxide and the magnesium oxide gains electrons.
All batteries have a positive and negative terminal. Electric current is a flow of atomic particles called electrons. Certain materials, called conductors, allow electrons to flow through them. Most metals (copper and iron as examples) are good conductors of electricity. Electrons will flow from the negative electrode of a battery, through a conductor, towards the positive electrode of a battery. Volts(voltage) is a measure of the force moving the electrons. Use of Copper and Zinc as the electrodes, and Sulfuric acid (the liquid in a fruit or vegetable) as the electrolyte is a proven method for this process.
The components of a fruit or vegetable that affect the amount of electricity produced is the liquid in the fruit or vegetable itself. The liquid is composed of sulfuric acid, water and a various other liquids. Sulfuric acid is the only thing that the fruit produces or is used to make a battery work.
My hypothesis is that: If the electrolyte source is changed (potato, apple, lime, lemon), then the production of energy (measured in volts) using a lemon will produce the highest voltage because the acid content in the fruit or vegetable will produce electricity when in contact with the electrodes (both zinc and copper).
My hypothesis states that the lemon will produce the greatest voltage. The reason I chose this fruit is because it is the prime candidate for the production of the acid content needed to have a higher voltage because there is more liquid in the fruit.
Hila Research Center. (n.d.). Lemon Battery . Retrieved November 21, 2011, from Hilaroad: http://hilaroad.com/camp/projects/lemon ... ttery.html
HTWSP. (2009). Apple Battery Project. Retrieved November 21, 2011, from how-things-work-science-projects.com: http://www.how-things-work-science-proj ... ttery.html
MS. (n.d.). Make a Battery from Potato. Retrieved November 2011, 2011, from Mini Science: http://www.miniscience.com/projects/PotatoElectricity/
Scott. (2009, April 15). Physics & Physical Science Demos, Labs, & Projects for High School Teachers. Retrieved November 21, 2011, from Word Press.org: http://teachingphysics.wordpress.com/20 ... e-battery/
David Macaulay, N. A. (1998). Batteries. In D. Macauly, The New Way Things Work (pp. 268-269). Boston: Houghton Miffllin Company.
If the electrolyte source is changed (potato, apple, lime, lemon), then the production of energy (measured in volts) using a lemon will produce the highest voltage because the acid content in the fruit or vegetable will produce electricity when in contact with the electrodes (both zinc and copper).
• Independent Variable: The electrolyte source (potato, apple, lime, or lemon)
• Dependent Variable: The voltage
o Same person doing the testing
o Use of same voltmeter
o Same leads, wires
o Conduct experiments in same location
o Same fruit or vegetable
o Same copper penny and same zinc nail.
• Standard of Comparison: Test the metal leads together, they should not produce any electricity, if they do, wipe of the leads and try again
• Digital Voltmeter that reads tenths of a digit
• 2 potatoes
• 2 lemons
• 2 apples
• 2 limes
• 6 pennies
• 6 zinc nails
• 2 metal leads
1. Hook up one single fruit or vegetable with one copper penny, inserting it one half inch into the fruit or vegetable.
2. Stick the zinc nail one inch into the other side of the fruit or vegetable.
3. Test the voltage by pressing the metal leads on the copper penny and zinc nail.
4. Read the voltage and write results in science notebook.
5. Wipe off the metal leads for next fruit or vegetable.
6. Connect the other fruits and vegetables the using the stated method above (steps 1-5), testing and writing down results.
7. Repeat steps one through six (three times).
8. Record and compile all results in a graph.
If you have any suggestions please help! Thanks!