Life Science Curriculum 8-12

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Submitted by: Elizabeth Joy Cabrera

Position: N/A

Institution: Azusa Pacific University

Title of Experiment: Making a Battery (Adapted from Student Activities in Basic Science for Christian School. 1983. Bob Jones University Press. Greenville, South Carolina.)

Materials Needed:

Aluminum strip
Copper strip
Zinc strip
Iron strip
250-ml beaker
0.1 M hydrochloric acid (HCl)
Vinegar
2 alligator clips
Ammeter
Voltmeter

Scientific Background of Experiment:

When two different metals placed in a liquid that has ions, also known as an electrolyte, are connected to an outside conducting path with a wire, a current will flow. One metal will pull electrons from the other through a wire. The metal atoms with more pull on electrons will be the anode and the metal atoms with less pull on electrons will be the cathode. This is the theory that explains the operation of a battery. The chemical reaction that occurs in the battery creates a difference of potential energy between the terminals of the battery. This potential difference (voltage) causes a current to flow in the circuit.

Methodology:

1) Clean the strips of aluminum and copper metal with steel wool and connect them to wires with alligator clips. Without letting the two strips touch, place them in a 0.1 M HCl solution. This is the battery.

2) Attach the wire from the copper strip to the positive terminal of the ammeter. Attach the wire from the aluminum strip to the negative terminal of the ammeter. Record the reading.

3) Replace the ammeter with a voltmeter, and attach the wire from the copper strip to the positive terminal and the wire from the aluminum strip to the negative terminal. Record the potential difference reading.

4) Safely dispose of the acid in the beaker and rinse off acid from the beaker and the metal strips.

5) Pour vinegar in the beaker and make another aluminum-copper battery by repeating step 1.

6) Record the current flow and the voltage.

7) Make a zinc-copper battery using HCl and record voltage and current flow.

8) Replace the HCl of the zinc-copper battery with pure distilled water.

9) Record the current flow and the voltage.

10) Compare the current flow and voltage of the different metals and the different solutions.

 

Misc. Helpful Information/ Hints/ Suggestions:

1) Metal strips can be obtained from scientific supply houses where they are listed as "electrolytic cells".

2) Make sure that the ammeter being used can measure at least a .1 A reading.

3) For further learning purposes, a teacher may want to ask the following questions:

(a) Which combination of metals gave the higher voltage?

(b) Which solution produced the higher voltage?

(c) Which solution was most acidic?

(d) What happened as the battery operated?

(e) What is the difference between voltage and current?