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Island Power Plant



Once you've taken care of basics like food and water, you'll want to experiment with ways to create your own electricity and electrical gadgets. Why don't you employ a little rough science to create a power plant on your island?

The Challenges!



Make a Battery

Some kinds of batteries produce electricity by a chemical reaction between two different metals (electrodes) immersed in acid (electrolyte). Figure out how to make your own batteries in case the limited supply on the island runs out.

You'll need:

  • two wires with the ends stripped off
  • aluminum foil
  • scissors
  • small bowl
  • warm water
  • salt
  • tape
  • 6 pennies (copper coins)
  • paper towels
  • 1.5 volt penlight light bulb
  • a paper plate

Battery

What you do:
Partially dissolve 1 tablespoon of salt in 1 cup of warm water. Some salt should still be evident in the bottom of the bowl. Place a penny on the aluminum foil and draw around it. Repeat five times. Do the same thing with the paper towel. Cut out the circles. You should have six foil circles and six paper ones. Tape the end of one wire to a foil circle. Dip a paper circle in the warm, salty water. Place the foil circle with the wire on the plate, and put a wet paper circle and a penny on top of it. Using all the foil, pennies, and paper circles, build alternate layers. Then tape the other end of the wire to the last coin and put it on top. This is your battery.

Test the battery with the light bulb. Attach the end of one wire to the metal terminal end of the light bulb. Wrap the end of the other wire around the metal shaft of the light bulb. Can you see the bulb light up?

What's going on?
The metal atoms in the foil dissolve into the electrolyte (the warm, salty water) and electrons are left behind. Electricity is created when the electrons flow through a circuit (the foil circles and paper circles soaked in warm, salty water). When the metals eventually dissolve completely into the electrolyte, no more electrons are formed and the battery stops working. The first battery (Volta's Pile) was developed about 1860 by Alessandro Volta. He stacked discs of copper, zinc, and cardboard soaked in salty water in alternate layers and measured an electronic current.

Activity adapted from Neil Ardley. 101 Great Science Experiments. Dorling Kindersley, 1993. For instructions on creating a similar battery, see http://www.exploratorium.edu/snacks/hand_battery.html.

For more information, see Rough Science episode 5: "Sun and Sea"



Build an Electric Motor

It's hard to sleep at night because of the heat. How would you go about building a simple motor to turn a paper windmill and create a breeze? When a current passes through a coil of wire it turns the wire into an electromagnet which interacts with a permanent magnet to make the coil spin. The spinning coil is a basic motor.

You'll need:

  • 5 small magnets (available at electronics stores)
  • 2 large paper clips
  • plastic, paper, or foam cup
  • 2 feet of solid insulated 20-gauge copper wire (non stranded)
  • masking tape
  • a 1.5 volt D cell battery in a battery holder
  • 2 alligator clip leads (available at electronics stores)
  • wire strippers
  • broom

Electric Motor

What you do:
Wind the copper wire around the end of a broom handle to create a coil with a 1-inch diameter. Take each end of the wire and wrap it around the coil to hold the coil together. Leaving about 2 inches of wire sticking out from each end, strip the insulation off these two ends using wire strippers. Attach three magnets to the bottom of the cup with masking tape. Turn the cup upside-down and lay two magnets on top. (The magnets underneath create a strong magnetic field and keep the magnets on top in place with no tape.) Unfold one end of a paper clip and tape it to one side of the cup so that the rest stands up above the cup. Unfold the other paper clip, and tape it to the other side of the cup. The paper clips will form a cradle for the coil. Attach one end of the coil to one paper clip and the other end of the coil to the other paper clip. Spin the coil and adjust the height of the paper clips to make sure that there is around 1/16 of an inch between the coil and the top of the magnets. Adjust the clips to make sure the coil stays balanced and centered. Put the battery and battery holder beside the cup. Attach one end of an alligator clip to a battery terminal and the other to a paper clip. Attach the other alligator clip to the other battery terminal and the other paper clip. Spin the coil to start it turning.

What's going on?
The current running through the coil of wire creates an electromagnet. What does this mean? As with a bar magnet, one end of the coil has become a North Pole, and the other a South Pole. Each of the three magnets attracts its opposite pole and repels its like pole of the coil, causing the coil to spin.

For more information, see Rough Science episode 5: "Sun and Sea"



Make a Flashlight

When you're on the island, you can't just flick a switch and turn on a light. There isn't a constant electricity supply. But with a flashlight, you'll be able to see around your room at night and even venture outside for a walk — moonlight or no moonlight.

You'll need:

  • 2 batteries with 1.5 volts each
  • 2 brass paper fasteners
  • sharp pencil
  • screwdriver
  • aluminum foil
  • plastic tape
  • a light bulb in a bulb holder
  • 3 pieces of wire with bare ends
  • paper clip
  • cotton
  • empty dishwashing liquid bottle
  • scissors

Flashlight

What you do:
Cut the top off the empty dishwashing liquid bottle. Tape foil shiny side up to the inside of the bottle top. Use the pencil to make two small holes in the side of the bottle near the bottom. One hole should be about an inch below the other. Firmly attach two pieces of wire to the bulb holder. Tape the top of one battery to the bottom of the other to make one long battery. Tape the third piece of wire to the bottom of the battery. Tape one of the wires from the bulb-holder to the exposed terminal on the battery. Put the long battery in the bottle, carefully threading the wire from the bottom battery through the lower hole. Stuff cotton in the space between the batteries and the walls of the bottle to keep the batteries in place. Thread the wire from the bulb-holder through the top hole in the bottle. Attach paper fasteners to the two wires poking through the holes and push in the fasteners. Put the bulb-holder on top of the battery and tape the center of the bottle top over the bulb. In other words, put the bottle top on back-to-front so that the aluminum foil is visible. Bend the paper clip and fit one end under the lower paper fastener to make a switch. (When the switch is turned, current flows from the battery along the wires to the bulb.) Press the other end of the paper clip against the top fastener and see the flashlight light up.

What's going on?
There is a thin wire (a filament) inside the bulb that glows white-hot when current flows through it. The light reflects off the foil to produce a bright beam of light.

For more information, see Rough Science episode 5: "Sun and Sea"



Create a Buzzer

The island can be a spooky place, especially at night. Since there is no phone system, you can't call for help if there's a problem. You can, however, create your own alarm system. Try using an electromagnet to make a buzzer!

You'll need:

  • 9 feet of PVC-covered wire with both ends stripped
  • iron or steel bolt
  • modeling clay
  • an empty thread spool
  • steel nail file
  • rubber band
  • scissors
  • plastic tape
  • thick cardboard
  • soda can
  • switch
  • 4.5 volt battery

Buzzer

What you do:
Firmly wrap the wire around the bolt 200 times (leaving both ends of the wire loose). Use the clay to fix the bolt to the cardboard. Turn the spool on its side and attach the handle of the nail file to it with the rubber band. Using the scissors, scrape away the paint at the base of both sides of the can. Tape one end of the wire to the metal part of the nail file, and attach the spool to the cardboard with clay. Cut the two wires. Attach one end to the battery and the scraped part of the can, and the other to the battery and the switch. Stick the can to the cardboard with modeling clay and touch the other scraped part of the can with the nail file. Connect the switch and press it. The can gives off a loud buzz. The vibrating nail file repeatedly strikes the can. Both the buzz and the nail file stop when you release the switch.

What's going on?
The buzzer uses magnetism to make a loud sound. Electricity flows from the battery through the can and into the nail file. Every time the nail file hits the can, electricity flows through it to the electromagnet formed by the bolt and wire, through the switch, and back to the battery. The electromagnet pulls the file away from the can. As a result, the electricity stops, and the nail file springs back, striking the can again and setting everything in motion once more. It's the movement of the electromagnet that makes the buzzing sound.

For more information, see Rough Science episode 5: "Sun and Sea"



Suggestions for other activities:

  • To communicate with other people, make a telegraph.
  • To see how much power you have, build a charge detector.
  • To check for materials that act as conductors, create an electricity probe.