Exploring an AM/FM Radio

Description

Physical radios of the 80s and 90s, though a staple of music culture at the time, have evolved to a point wherein many school-age children may not recognize their physical appearance, how to tune one, or how one works. This activity serves as an introduction for younger children who may need to be introduced to a physical radio, rather than one they may be more familiar with such as satellite radio within a car or a Music Genome program on a smartphone.

In this activity, students will physically explore an AM/FM radio, and build a radio tuner to further understand how one works.

Materials

A portable AM/FM radio with a moveable dial/ tuner: some brands can be purchased new (Jensen, Studebaker), used/ borrowed is also fine

Two sheets of paper (per student)

Tape

Outline-Introduction

1.      Ask students how they listen to the radio. Many will probably mention cars, but some may also mention Alexa/ Echo Dot devices, or smartphone. Tell them that using radios to listen to music, the news, or shows has a very long history that continues up through today.

2.      Have them explore the dial radio. Have them clarify what parts are familiar to them and if they understand how to tune it to the station that they want. Use the class’s knowledge to guide how much you share/ teach them. Some classes will be more knowledgeable than others.

3.      Explain that they may be familiar with “satellite radio” (Sirius XM.) Satellite radio still plays music over radio waves, just like the portable radio does, but the portable radio relies on a signal from a local radio station instead of from a satellite.

a.      Try finding a station that you can barely hear/ near-static. Look up its location online. Now, find one that comes in clear and find its location online. Have the class map them out to understand that a portable radio needs a local station for clearer sound.

4.      Some students may be familiar with a program like Pandora Radio, which was created through the Music Genome Project. Essentially, the MGP has broken down songs by different attributes (melody, rhythm, lyrics, etc.) and in turn can group similar songs and play them in sequence. This is opposed to a radio station, where a human decides what songs to play based on an agreed upon music genre (rock, country, top 40, etc.)

Outline-Build a Tuner Adapted from Communicating Through Radio Waves: Frequency Flyer, fromNational Science & Technology Week 1997

1.      Each student/ group will need two pieces of paper. Roll the papers up together so that one nests inside of the other. Tape both shut so they don’t unroll.

2.      While pressing one end of the outer tube to their ear, have students slide the inner tube in and out of the outer tube.

a.      What do they hear when the tube is longer? Shorter?

3.      Introduce the portable radio again. When the dial is turned, it is “tuning” the radio, or adjusting it so that it will pick up a specific length of radio wave. The same is happening when the length of the paper tube is changing, it is picking up on sounds differently. Though their voices may all be audible through the tube, especially if the students are right next to each other, how does the pitch change? Are some sounds clearer than others?