Science Fair Project Ideas – Quick and Easy Project #5 – Crystal Radio
Of all the fun science fair project ideas, this one is my favorite for students that want to learn more about modern communication techniques and technologies. Through this experiment, students will build their own radios that actually work and can house project ideas be tuned. This is also one of the cool science fair project ideas for students that are interested in technology and engineering, as well as communications.
Like all science fair project ideas, this project requires some materials to gather in advance, but the cost is still under $50. Also, students need to be careful that they are safe when working with any kind of electricity.
Through this experiment, students will build a radio receiver from the ground-up. They will also fine-tune the radio to improve its performance.
Radios are an integral part of our culture. They help us communicate across the same house or across an entire world. Using this crystal radio, students will understand the fundamentals behind building a functional radio system.
Terms and Concepts You’ll Need to Know:
This experiment relies on a series of terms and concepts that students will learn before or during the experiment, including the following:
Radio frequency and radio wave
FM radio frequency (amplitude modulation)
Power and electricity
Materials You’ll Need:
To complete this project, you’ll need a variety of materials that may take awhile to gather, including:
1 round oatmeal box
1 wooden mounting board
1 spool of plastic insulated wire (100 feet)
1 germanium diode
1 47 kohm resistor
1 alligator clip
1 ceramic earphone
4 fahnestock clips (optional)
In order to perform this procedure, you may want to have a parent present. As with many science fair project ideas, safety should come first.
Thread wire through 2 small holes that you poke about 1/2 an inch down into the oatmeal box. The wire should come out on the outside of the box. Use about a foot of the wire on the outside of the box to use as the connection to the circuit. Take the remaining wire inside the box so it does not slip.
Wrap the wire around the box 5 times. Remove some of the plastic insulation to twist the wires together.
Make wraps every 5 turns until you reach 40 turns total.
Once you reach 40 turns, poke another 2 holes into the box. Cut another foot of the wire off in order to leave extra wire on the outside of the box. Push the wire back through the hole so that it comes out on the exterior of the box. Take the wire on the inside of the box.
Use an antenna and ground. This can be any wire that is not insulated. Place the antenna as high as possible, but not near electrical wires.
Ground the antenna to a water pipe or metal rod that is at least 2 feet underneath the ground.
Hook the wire to an alligator clip and a center tap. Hook the wire again to the earphone. Listen until you hear a noise. You may need to modify the radio to hear a noise if you do not hear it at first.
This is one of the great science fair project ideas, but it may take awhile to build and perfect. Always put safety first and work with a parent to make sure you are completely safe. Finally – have fun!