# Electrical and Chemical Energy

#### FOR MAKEUP WORK:

Complete Energy Skate Park Activity- Google Form using the PHET simulator.

## Energy Skate Park

Today you will experiment with an online PHET simulator set at a skate park. First, you will make predictions of graphs before using the simulator to create graphs of energy vs. time under different conditions. While completing this simulator you should be thinking of these big ideas:

• THE CONSERVATION OF ENERGY
• GRAVITATIONAL POENTENTIAL
• KINETIC ENERGY

Predicting the behavior of something based on prior knowledge is an important skill for engineers. When engineers are designing, they make predictions about how structures, devices and processes will function before they build them.

## Predicting

On your own and on a separate sheet of paper: predict what the first two graphs will look like on the "Energy Skate Park Work Sheet" found below. This is Page 1 titled "Prediction Time"

Energy Skate Park Work Sheet

## Energy Skate Park Activity

On one computer, open the Energy Skate Park, on a second computer, open the Energy Skate Park Work Sheet and Simulator Answers Google Form in two separate windows. Follow instruction on the Energy Skate Park Work Sheet then Answer Questions on Google Form.

"When electrons are forced to move along a path in a conducting substance such as a wire, the result is energy called electricity. Electrical energy is energy carried by moving electrons along this pathway. Conductors of electricity do a good job of allowing the flow of electrons. Metals are good conductors and that is why most electrical circuits use metal wires. Although electricity cannot be seen, it is one of the most useful forms of energy.

Power plants do not create electrical energy, however. Since energy is neither created nor destroyed, according to The Law of Conservation of Energy, electrical energy is a result of energy transformations. For example, power plants can convert chemical energy stored in fuels into thermal energy, which evaporates water into steam, which produces mechanical energy as it moves through turbines. The turbines spin generators, which in turn produce electricity. This electrical energy is used to power lights, heaters, and appliances in homes.

Electrical energy is also seen in the form of static electricity. Static electricity is the build-up of charge (electrons) in one location. (Static means to “stay still”, or in “one location”.) When this build-up of charge is released, the electrons will flow giving off heat, light (lightning), and sound (thunder) in the process.

Electrical Potential is the potential energy a charge has due to its location in an electrical field. Electrical potential is measured in volts (electrical potential energy per charge). The unit “volt” is named after the Italian physicist Alessandro Volta who invented what is considered to be the first chemical battery. Since electrical potential is measured in volts, it is commonly called voltage. Voltage is the amount of potential energy between two points on a circuit."

(Sourced From Energy Right Solutions for Youth: Edu Purposes Only

http://www.dicksonelectric.com/Portals/des/ERSY/PDFs/2.8%20Electrical%20Energy.pdf)

For more Help on Electricity, see these links

https://science.howstuffworks.com/nature/natural-disasters/lightning.htm

http://www.eschooltoday.com/energy/kinds-of-energy/what-is-electrical-energy.html

# Battery Assembly

1. Make a saturated salt solution by adding salt to water and stirring until it doesn't dissolve anymore. Add a splash of vinegar to this solution.
2. Cut your matboard into four 1/2-inch squares, each about the size of a penny. Soak the pieces in the salt-and-vinegar solution. Once the pieces are thoroughly wet, take them out and place them on a paper towel so they are still damp, but not dripping.
3. Use sandpaper to remove the copper from ONE side of each of four pennies. Leave the fifth penny intact. Sand until you see zinc (shiny silver color) covering the entire face of the coin. This takes some time and effort, so be patient. Try placing the sandpaper on a hard surface and moving the penny instead of the sandpaper. The "tails" side may be easier to sand because the Lincoln Memorial (or Union Shield) doesn't protrude as far as Lincoln's head. When you're done, the sanded coins should have a bronze-colored copper side and a silver-colored zinc side.
4. Take one of your sanded pennies with the zinc side facing up (copper side down), and place a damp piece of matboard on it. Then stack another sanded penny (again, zinc side facing up) on top of this. Take your next piece of matboard and place it on top, and continue stacking pennies and matboard on top of each other to make a neat pile. Finally, place the unsanded penny at the very top.
5. When you're done, you should have alternating layers of pennies and matboard with all the zinc sides facing up, and both the very top and the very bottom of your stack (facing down) should be copper. Make sure the pennies aren't directly touching each other and, likewise, that the pieces of matboard aren't touching each other.
6. Test your battery by connecting your LED. Touch the longer lead to the intact penny on the top and the shorter lead to the bottom of the stack. Make sure that the leads don't touch any other layer. Did the LED turn on? If not, make sure the LED leads are oriented correctly and use a paper towel to wipe off any excess water from the penny-matboard stack.

## To Do and Notice

Take one of your sanded pennies with the zinc side facing up (copper side down), and place a damp piece of matboard on it. Then stack another sanded penny (again, zinc side facing up) on top of this. Take your next piece of matboard and place it on top, and continue stacking pennies and matboard on top of each other to make a neat pile. Finally, place the unsanded penny at the very top

.

When you're done, you should have alternating layers of pennies and matboard with all the zinc sides facing up, and both the very top and the very bottom of your stack (facing down) should be copper. Make sure the pennies aren't directly touching each other and, likewise, that the pieces of matboard aren't touching each other.

Test your battery by connecting your LED. Touch the longer lead to the intact penny on the top and the shorter lead to the bottom of the stack. Make sure that the leads don't touch any other layer. Did the LED turn on? If not, make sure the LED leads are oriented correctly and use a paper towel to wipe off any excess water from the penny-matboard stack.

## What's Going On?

Batteries are devices that convert chemical energy into electrical energy. When two different metals are connected by an electrolyte, a chemical reaction occurs at each metal surface, called electrodes, that either releases or uses electrons. When these electrodes are connected by a wire, electrons will move from one surface to the other, creating an electric current.

Pennies that were made after 1982 have zinc cores that are plated with copper. By sanding off one face of a penny, you create a zinc electrode that can pair with the copper electrode on the face of the next penny. The matboard soaked in salty vinegar water serves as the electrolyte between the two terminals.

Each zinc-matboard-copper stack represents one individual cell. By stacking additional matboards and sanded pennies, you’ve created a battery, which is a series of electrochemical cells. This is also called avoltaic pile, which is named after Alessandro Volta, who created the first battery in 1800 by alternating zinc and copper electrodes with sulfuric acid between them. In Volta’s battery and your penny battery, an oxidation reaction occurs at the zinc electrode that releases electrons and a reduction reaction occurs at the copper electrode that uses them.

With a voltmeter, you can see that each cell can generate over 0.6 volts. The penny battery you created for this Snack has four cells. A stack of three cells should generate enough voltage to light a red LED, which usually require around 1.7 volts.

# Going Furthr

Before 1982, pennies were made of 95% copper, but the rising costs of copper led the United States Mint to change the composition of the penny. The metal content in a pre-1982 penny is actually worth more than its one-cent face value. Consequently, in December, 2006, the United States Mint implemented regulations that prohibit the melting or treatment of all one-cent coins.

Legal disclaimer: The Exploratorium does not take responsibility for any damaged coinage, and certainly don’t try to sell your completed battery for more than 5¢!