A Salt and Battery - The whole Shocking Story!

1 This experiment with a few coins and lemon juice recreates an experiment first performed by Alessandro Volta in 18th century Italy creating a battery, using the reactions between ions and metals to create an electric current.

1.1 Materials:

Lemon Juice (or vinegar with a bit of salt added)
2.5cm x 2.5cm squares of paper towel
5 pennies (or other copper coins)
5 dimes (or other coins made out of a metal other than copper)

1.2 Procedure:

Soak the paper towels with lemon juice
Stack the coins, alternating pennies and dimes, placing a piece of paper towel between each coin pair, like this:

penny/dime/paper/penny/dime/paper/penny/dime/paper/penny/dime/paper/penny/dime/paper/penny/dime

Moisten both your index fingers and hold the pile¹ tightly between these fingers

1.3 Observations:

If all goes well, you'll feel a small shock or a tingle.

1.4 Conclusions:

The lemon juice contains an acid (ascorbic acid, or vitamin c, to be precise) which means that there are charged particles (or ions) dissolved in the fluid specifically positively charged hydrogen ions and the ascorbate ion (which is negatively charged - and called an anion "Anne Ion").

The hydrogen ions want to absorb electrons and pair up to form neutrally charged hydrogen gas. Similarly, the negative ions want to give up their extra electron (or find something positively charged to bond with) so that they are also neutrally charged.

Depending on the exact metals used in the coins, one type of coin will be "better" at giving up its electrons than the other (which one depends on the exact composition of the silver coin). The hydrogen will preferentially collect at this coin (or electrode), making it positively charged.

The negative ions will collect at the other coin, making it negatively charged (called a cation "Cat Ion". This process continues through the pile of coins, until we end up with a large positive charge at one end and a large negative charge at the other. Once you place the coins between your fingers, the electrons, which are repelled by each other move through your body to get to the positively charged end giving you a mild shock.

2 Questions About Chemical (not storage) Batteries.

"Use another sheet of paper, and complete sentences to answer these questions."

How is this battery you just made different than a battery you buy?
Can you think of a way to make a stronger battery? Describe your ideas.
How does an alkaline battery work?
Why can't regular alkaline batteries be recharged?
What is the single biggest drawback to using batteries to power anything but small appliances?
What are the biggest differences between different brands of batteries?
Draw a simple battery powered circuit in series.
Draw a simple battery powered circuit in parallel.

Footnotes:

¹As in Voltaic Pile. Thank you Count Alessandro Volta!

File translated from T_EX by T_THgold, version 3.70.
On 30 Mar 2006, 06:18.