Science Fair Ideas

A solar powered dc motor is a simple demonstration of how solar power can be used directly in some applications. Solar panels transform light energy into electrical energy. The electrical energy from the solar panel is direct current or dc electricity so it can be used by motors that run on dc electrical power.

Motor Directly Powered by a Solar Panel

If we hook up a solar panel directly to a dc electrical motor as shown in the picture, then the solar panel is sending power directly to the motor and the motor is using the electrical energy immediately. In this case the motor is "Directly Powered by Solar Energy".

Motor Indirectly Powered by a Solar Panel

If we hook up the solar panel in a parallel circuit with a motor and a battery then the solar panel will charge the battery and the dc motor will get dc electrical energy from the battery. The energy used to power the motor came from the battery. However, the energy in the battery came from solar energy so we say that the motor is "Indirectly Powered by Solar Energy".

Science Fair Project Idea/ Objective:

This is a simple idea that can be added to your science fair project to help demonstrate applications of solar energy. You can also use this solar powered dc electrical motor and spinner as an additional demonstration and test instrument for the science fair topics on Amount of Light that Hits a Solar Panel, Angle of Light that Hits a Solar Panel, Wavelength of Light that Hits a Solar Panel and Concentration of Light on a Solar Panel.

Tip:

Create something, like a spinner, that you can attach to the motor so that when the motor spins it will be easy to tell that it is working. See the picture at the top of this page for an example of spinner. Below there are instructions on how to make a spinner for your motor.

Materials:

1. Solar Panel
2. dc electrical motor
3. Spinner
   1. Wooden Dowel (about 1/2" diameter)
   2. Drill to make a hole in the dowel
   3. Cardboard (about 6" x 6")
   4. Paper Image
   5. Glue

In Schemantic 1:

Light energy hits the solar panel and is transformed into dc electrical energy. The electrical energy passes through the wires to the motor. The motor runs!

In Schemantic 2:

Light energy hits the solar panel and is transformed into dc electrical energy. The electrical energy passes through the wires to the battery. The resistor keeps the electrical energy in the wires from flowing too fast. The diode works like a safety valve and keeps the electrical energy from flowing out of the battery and back to the solar panel when there is no light.

In Schemantic 3:

When you close Switch #1 and open Switch #2 the light energy hits the solar panel where it is transformed into electrical energy that passes through the wires to the battery.

When you open Switch #1 and close Switch #2 the energy that is stored in the battery passes through the wires to the motor and the motor runs!

Solar powered garden lights operate on the same basic principal except that they switch off and on automatically by using a photoresistor.

Set Up - Putting it all together:

1. Make the Spinner to attach to the motor
   1. Wooden Dowel with small hole
   2. Cardboard Circle
   3. Sun Image
   4. Glue
   5. Glue the spinner to the dowel and attach to motor
2. Connect the solar panel to the motor
3. Find some sun and watch it spin. For some solar panels you might be able to use a 100 Watt light bulb as the light source.

Further Reading:

Solar garden light at How Stuff Works.