Batteries & Circuits

two beakers, two dissimilar metals: copper (Cu) and zinc (Zn)
voltmeter, battery acid: Coke
two spacers, any piece of plastic

First build a one cell battery. Follow the drawing below:

What does the voltmeter read?
Now add about a 1" depth of Coke. What does the voltmeter read?
V=
Switch the leads so that they each attach to the opposite piece of metal. What does the voltmeter read?
V=
Predict what should happen if you add more Coke to the battery. Will the voltage change? What if you doubled the depth of Coke?
V=
Now add another inch of Coke. What is the new voltage reading? Try to explain your finding.
V=
Now you will build a two cell battery. Use should use the "U" shaped piece as shown below.

What do you think the voltage difference is between points 1 and 2? Between 2 and 3? Between 1 and 3?
Predictions
V₁₂= V₂₃= V₁₃=
Measure the voltages and compare with your predictions.
Measurements
V₁₂= V₂₃= V₁₃=

NOTE: Here is a diagram of the working principle of the battery:

From where does a battery get its power? Can you think of three other systems which operate in a similar manner.
How do a "D" cell and an "AA" cell differ?
How do a transistor radio battery and a "D" cell differ?

Aluminum foil strip
Flashlight bulb and one battery
Circuit boards with clip leads

Use one battery and an aluminum foil strip to make a flashlight bulb glow. Sketch the circuit.
Now using the circuit board and clip leads make one light bulb light up. Add a switch to the circuit to turn the bulb on and off.
Connect all four batteries in series and measure the voltage drop (potential difference) over the light bulb. Repeat this measurement at the terminal of the battery. Do you measure the same voltage drop?
Next, remove the light bulb from your circuit and make sure that you still have a complete circuit, once you close the switch. What voltage do you now measure at the battery terminals. Explain.