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Electricity Experiments

Simple Circuits Build a Dry Cell Battery Potato/Lemon Battery Homemade Electromagnet Squishy Circuits
Energy Detective Static Attraction AC/DC Conductivity History of Electricity

Simple Circuits

Materials:
insulated wire
wire cutters/strippers
an AA battery
a LED (or buzzer)

Safety note: never connect the ends of a battery with a single wire. This will cause the battery to overheat and possibly explode!

  1. Cut two lengths of wire about 15 cm long (6").
  2. Strip 1 cm (1/2") of insulation from each end of both wires.
  3. Attach (by twisting the exposed wire) one end of one wire to one of the LED (or buzzer) leads, and one end of the other wire to the other lead.
  4. Touch one loose end of one wire to one side of the battery and the other to the other side at the same time. If the LED does not light up, switch the sides around.
  5. You have created a simple circuit. If you look closely a the battery, you will see that one end is marked with a "+" and one with a "-". The electricity flows through the battery from "-" to "+" (negative to positive). Completing the circuit (by attaching the wires to the battery and LED in a circular pattern) allows the electrons to continue flowing, thereby powering the LED (or buzzer). Some LED lights only work in one direction, so that is why you may have needed to switch direction to make it work.
  6. You can make more complex circuits by adding switches, capacitors, resistors, more lights and/or buzzers, small motors, etc. For safety, it is best to consult a project manual to learn how to use these safely (especially the capacitors and resistors!).

Build a Dry Cell Battery

While not completely "dry", the dry cell (or more accurately, "pile battery") refers to batteries in which the electrolyte sits in a stack of alternating metals. In a "wet cell" battery, the electrolyte (often a strong acid) is a liquid.

Materials:
dry cell battery components pennies--at least 20
aluminum foil, cut into penny-sized pieces, at least 20 plus a piece cut to twice the width of the others
a paper coffee filter (or water colour paper) cut into at least 20 penny-sized pieces
white vinegar (about 2 Tablespoons) mixed with a sprinkling of table salt (this will make your electrolyte solution)
an LED
insulated wire, 2 pieces at least 8 cm (3") long with 1 cm (1/2") stripped from either end
optional: electrical tape
optional: a volt meter

  1. Soak the paper in the salt and vinegar.
  2. dry cell battery stack
  3. Wrap the longer piece of foil around one end of one of the wires. This will be your anode.
  4. Place a piece of soaked paper on top of one of the wire-linked pieces of foil, then add a penny. Repeat the pattern: foil, paper, penny until you run out. Top with the last penny, which will be your cathode.
  5. If desired, wrap electrical tape once around the stack to help hold it together. Leave the other sides open.
  6. Touch one loose end of one wire to one side of the LED and the other to the other side at the same time. If the LED does not light up, switch the sides around. If it still does not light up, add more layers until you are able to make it work. Ours took 35 but some of our pennies were newer and had a lower copper content than older ones. This meant that they didn't conduct the current as well as ones with more copper.
  7. Variations: Try using nickels and/or dimes instead of the foil, and also try older and newer pennies, as well as those from different countries. Which combination is most effective? You can also vary your electrolyte. Try using lime juice, very salty water, and cola. Which is most effective?

Potato Battery

Materials:
a potato (or a lemon, but first warm it by rinsing under hot water and roll it firmly against a hard surface to help the juices flow well)
a zinc electrode--a large galvanized nail works well
a copper electrode (use a piece of uncoated heavy copper wire or a small piece of copper piping)
an LED or digital clock with exposed leads
insulated wire, 2 pieces at least 8 cm (3") long with 1 cm (1/2") stripped from either end
optional: alligator clips for attaching the wire to the electrodes
optional: a volt meter

  1. Insert the electrodes into either side of the "top" of the potato (or lemon). Be sure that they reach at least 1 cm (1/2") into the centre.
  2. Attach one end of each wire to a LED or clock (or volt meter).
  3. If using alligator clips, attach those to the loose ends of the wires.
  4. Attach one wire to an electrode and the other wire to the other electrode.
  5. Wait a bit and watch to see if it works. If you are using an LED, you may need to switch electrodes if the light does not work after a few seconds.
  6. Variation: Try filling a small bowl with vinegar and a crumpled-up piece of aluminum foil. Insert your electrodes into either side of the bowl. What other battery sources can you find around the house? Will a tomato work? How about an apple? Which battery provides the most power?

Homemade Electromagnet

Materials:
insulated copper wire, fine gauge, at least 1/2 metre (18") but more is better!
a large nail or spike
a 9-volt battery (or smaller, such as an AA--never larger, or it will burn off the insulation of the wire and make an unsafe & nasty mess!)
insulated wire, 2 pieces at least 8 cm (3") long with 1 cm (1/2") stripped from either end
several paper clips and/or other items with iron in them
optional: a 9-volt battery cap, or 2 alligator clips, or electrical tape (for attaching the wire to the battery)

  1. Leaving about 3" (7 cm) of wire free on either end, start wrapping the wire ticghtly around the nail. Be sure to keep the coil tight together, but do not overlap the wraps.
  2. Attach either end of the wire to the battery leads.
  3. With the wires attached to the battery, try picking up some of the paper clips.
  4. How powerful is your magnet? What happens when you remove the wires from the battery?
  5. **Be sure to disconnect the wires from the battery after a few seconds of use. If you leave them attached for very long, the battery can overheat and possibly explode.**
  6. Variations: Try using longer and shorter lengths of wire with more and less wraps around the nail. Also try different sized nails/spikes. Which changes increase the strength of the magnet?

Energy Detective

Materials:
a Kill-o-Watt unit (most libraries offer these on loan)
a notebook and pencil for recording your results

  1. Read the instructions that come with the unit.
  2. Remove any plugs from the outlet you are testing, insert the Kill-o-Watt unit and plug the appliances back into the unit. Record the readings.
  3. Repeat this for all of your home's outlets, being sure to try it both with the appliances turned on as well as with them turned off. Some appliances (such as an electric range) may be on special hook-ups, so you may not be able to test those.
  4. Does simply turning off your television, microwave or computer mean that no electricity is being used?
  5. Try using a powerbar and repeating the experiment for the items that still read electrical consumption when they were turned off. If you turn off the power bar, is there any power being used anymore?
  6. What other sources of electrical consumption happen in your home? (Hint: think of air temperature!)
  7. What ways did you find your family could reduce their electricity use? Show your family what you found and discuss ways you can use that information to reduce your electrical consumption.
  8. Ask your parents for their electricity bills. During which months does your family use the most electricity? Record your home's electricity use over the past year, and then record your family's energy use over the coming year. How much difference did you make with the information you gathered with the Kill-o-Watt unit?
  9. You can also do this in your school or any other building that uses electricity and in which you have permission to work.

Static Electricity

Materials:
several balloons
confetti, rice, dry cereal, etc.
a flourescent lightbulb
a plastic comb
a dry day (it's best if the humidity level in the room is less than 50%)
a dark room or area
optional: a wool sweater or carpet

  1. Inflate your balloons and tie them off.
  2. Rub them against either your hair or a wool sweater or carpet.
  3. Sperad out your confetti/rice/cereal and bring your balloon towards it all. What happens?
  4. Now bring your comb, balloon and flourescent bulb into the dark area.
  5. Rub your balloon again and bring it close to the bulb. What happens?
  6. Try combing your hair and then bring your comb towards the lightbulb. What happens?

Explanation:

When you rub the balloon against wool or your hair, the balloon takes on electrons which give it a negative charge. This makes it stick to walls and attract the cereal etc. Your hair or the wool bnow has more protons than electrons, and as a result is now positively charged. When the negative charge (from the comb or balloon) is brought near the end of lightbulb, the electrons are discharged and create a small current of electricity in the bulb, which causes it to release light (photons). For a more detailed description of how flourescent lights work, check out this link at HowStuffWorks.

AC/DC

The batteries in the experiments above all run on direct current (DC). The direction of the flow of electricity always runs in the same direction. The electrons always move in the same direction. With the electromagment, the poles of the magnet remain the same as the current runs through the wire.
The electricity that runs into your home runs on an alternating current (AC). This means that the direction of flow of the electrons changes (60 times a minute!). It also means that an electromagnet made with AC power (do not attempt this yourself or you will be electrocuted!) will change polarity 60 times a minute!
We use AC to power homes because it makes it easier to increase the voltage (to help it travel large distances) and decrease the voltage (to make it safer for home use) using transformers.
Here is a visual demonstration on YouTube of how AC and DC power works.

Conductivity

Also see insulation for more related experiments.

Materials:
3 pieces of insulated copper wire with 1 cm (1/2") stripped from either end (any length will work)
a AA battery (or two if you have a holder)
a volt meter (and/or LED)
various items to test: a pencil, a crayon, paper, yarn, aluminum foil, various liquids, a stick, a glass rod, etc.
optional: a battery holder or alligator clips to connect the wire to the battery

  1. Connect one end of a wire to a battery lead. Repeat with a second wire.
  2. Connect the other end onf the first wire to the LED or volt meter.
  3. Connect the 3rd wire to the other side of the LED or volt meter.
  4. Test your connections by bringing the free ends of the wires together. Adjust as necessary.
  5. Once your circuit works, try testing materials for conductivity. Be sure to disconnect the circuit between each trial for a few seconds, and especially if either the wire or battery begins to heat up!
  6. Try this: on a piece of paper, make a heavy dark scribble with a regular pencil. Do the same with a wax crayon. Touch the wires to the graphite (pencil) scribble. What do you notice? Now try it with the crayon. Which makes a better conductor?
  7. Try filling several bowls with tap water. Add salt to one, baking soda to another and vinegar to a third. Which conducts best?
  8. Try using distilled water. How does this compare with tap water?
  9. Also try glass, wood, wool, copper, rubber, aluminum (foil), and other liquids such as cola, fruit juice, diluted household bleach, etc.




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