BY LOGAN INGRAM MY SCIENCE FAIR PROJECT

Big Question Will a crystal radio work and be able to play music?

HYPOTHESIS I believe that the crystal radio will play music from a radio station.

RESEARCH Crystal radios have always been made by hand. Crystal radios have not always been made with crystals but by spark gaps. Crystal radios have been made for many years. You do not always need a battery or electricity to power a radio. Only some radios play both AM and FM. A persons body can be used as an antenna, but you still need a connection to the ground.

MATERALS Germanium diode a channel dial a variable capacitor a plastic tube a radio base a ceramic earphone four metal fasteners two 1m coated wires a 10m non-coated wire two small screws and one large screws eight metal washers 4cm coated wire

INSTRUCTIONS Wind the 10m non-coated wire around the plastic tube, leaving 15cm of wire unwound on both ends. Attach the plastic tube to the radio base. Attach the variable capacitor to the radio base with two of the small screws. Take the dial and attach it to the variable capacitor with the large screw. Put one washer over each fastener. Put one end of the germanium diode and one wire from the earphone through the fastener then place another washer on the end under the wires. Place the fastener through a hole in the radio base and spread the fastener to attach. Put the other end of the germanium diode, one end of one of the 1m wire (antenna), one wire from the variable capacitor, and one end of the 10m wire through a fastener then place another washer on the end under the wires. Repeat step 7. Put one end of the second 1m wire (ground), the second wire from the earphone, and one end of the 4cm wire through a fastener then place another washer on the end under the wires. Repeat step 7. Put the other end of the 10m wire, the other end of the 4cm wire, and the second wire from the variable capacitor through a fastener then place another washer on the end under the wires. Repeat step 7. Hold the ground wire against a water pipe and hold the antenna wire in the air and turn the dial till you hear something.

Control/Variables When the radio is not hooked up to an antenna/ground you cant hear anything. When you move the dial, you are able to tune in radio stations.

Observations from experiments I observed that if any wire got disconnected from the ground or antenna the whole radio would shut down. By adjusting the dial, I was only able to tune in one radio station. Any metal object can be used as an antenna but the “ground” connection must go into the ground.

Data By adjusting the tuning knob I can only hear one radio station. That station is an AM station and I can not connect to an FM station.

Analysis of Data The data shows that while I was not able to hear music, I could get a radio station that gave the weather report. That station was KOA radio.

Conclusion While my hypothesis incorrect overall the crystal radio worked. I was able to hear a radio station, but it was weather instead of music.

References I got part of my information from sciencebuddies.com and google.com.