Will sunlight make a motor run?

From Experiment Central, published by U·X·L and available online in Science Resource Center.

Purpose/Hypothesis

In this project, you will be working with photovoltaic cells, or solar cells, which utilize the photoelectric effect to convert solar energy into electricity. This project will allow you to determine if you can operate a small electric motor with solar cells. It will also let you determine how many cells and how much sunlight it takes to operate the motor.

Level of Difficulty

Easy/moderate.

Materials Needed

• 3 solar cells (.5-volt rating each)
• 1 DC motor (l.5-volt rating)
• 4 jumper wires with alligator clips on each end—three about 4 inches (10 centimeters) long, and one about 12 inches (30 centimeters) long
• stopwatch or clock
• marking pen
• posterboard or a small table to support the experiment
• cardboard to provide shade, about 24 inches (60 centimeters) square

Approximate Budget

$25. (Supplies can be purchased at an electronics store.)

Timetable

About 30 minutes.

How to Experiment Safely

Handle solar cells carefully. They are fragile and break easily.

Step-by-Step Instructions

1. Place the jumper wires with alligator clips on the + and - terminals of the solar cells. Attach the other ends to the motor terminal. Be careful to match the + or - connections. Place the experiment on a piece of posterboard or a small table so you can move it around.
2. Make a small mark on the shaft of the electric motor with the marking pen.
3. Test the ability of the solar cells to power the motor under different lighting conditions, such as the following: outside on a sunny day; outside on a sunny day, but shaded by the cardboard; inside on a sunny day, but out of direct sunlight; inside in a dark room; inside at night under an incandescent and/or fluorescent light bulb.
4. Record how many rotations the motor makes in 10 seconds — or if it runs at all — under each condition, using a chart.

Summary of Results

Study your results. Under which conditions did the solar cells operate the motor? How many rotations could you record? Write a paragraph summarizing and explaining your findings.

Troubleshooter's Guide

Problem: The motor does not rotate under any condition.

Possible cause: The connections may be loose. Check them connections and try again.