Coin Battery

Here is an experiment.

Materials:

• 10 quarters
• metal kitchen foil
• blotting paper
• 2 pieces of copper wire(taken from any electrical wire or flex)
• cider vinegar
• salt
• bowl
• LED-a light emitting diode(available at model and hardware shops)
• masking tape

Steps:

1. Mix vinegar and a little salt together in the bowl. Vinegar is acetic acid and all acid can be used as an electrolyte. Sulfuric acid is found in car batteries, but don't fool around with something that powerful. It eats clothing and can burn skin - unlike vinegar, which goes on your salad. Common salt is sodium chloride, a combination of positive and negative ion. (Na+ and Cl-) These will separate in the electrolyte, increasing its strength.
2. Soak your circles of blotting paper in the ion-rich electrolyte.
3. With the masking tape, attach the end of one wire to the underneath of a foil disk. This is the negative terminal. Now stack in this sequence - foil, paper, coin, foil, paper, coin. Each combination is its own tiny battery - but to light even an LED (light-emitting diode) you'll need quite a few. A car battery tends to have six of these, but with a much larger surface area for each "cell." As a general rule, the bigger a battery is, the more power it has. (power measured in watts = amps x volts.) All the positive ions will go to one terminal, all the negative ions to the other. In effect, you are charging your battery.
4. When you have a stack, you can attach a wire to the last coin with tape. This will be the positive terminal. They can now light an LED or with enough coin batteries, even a small bulb.

From: The Dangerous Book for Boys. Conn Iggulden, Hal Iggulden. 2007

How to WOW the Audience

If you're here reading this column, I'm guessing you're wondering how to WOW the audience. Well you've come to the right place. If you're in a science fair and have to have a display you want to make it as colorful as possible without going overboard. If you want a more professional look use neutral colors. You should also have a stunning science experiment to, as I say, WOW the audience. Now that you,ve learned how to WOW the audience, let's get going with the experiments.

Wrinkly Apple

Here's an experiment.

Materials:

• One apple
• One popsicle stick
• One plastic bag
• 1/4 cup of salt
• 1/2 cup of sodium carbonate (powder bleach)
• 1/2 cup of bicarbonate of soda

Steps:

1. Mix salt, sodium carbonate, and bicarbonate of soda together in plastic bag
2. Cut a face into the apple by using the popsicle stick. Push popsicle into the top of your apple so it makes a handle.
3. Put the apple into the mixture in the bag, so it is covered.
4. Leave the bag open, in a warm place. Watch what happens to the apple.

CAUTION: Do not eat the apple once it is wrinkly!

Found in: 501 Science Experiments. Hinkler Books.