# "And Now, a Word from Our Sponsor." (Studying Radio Commercials)

## Article excerpt

Student Activity Goals

Students will -

* collect and display data in a circle graph,

* explore proportional reasoning,

* identify and describe patterns and common characteristics for a given collection, and

* communicate mathematical ideas in a variety of ways.

Materials

The materials needed are -

* one copy of the reproducible page for each student,

* calculators,

* straightedges for drawing circle graphs, and

* cassette recorders and tapes.

Planning for Instruction

Begin by asking students to describe radio commercials that they have heard. Encourage them to identify the names of products typically advertised on the radio and to think about the format of a typical radio commercial. For example, what makes some commercials more memorable than others? Is the product name or the jingle generally identified early or late in the ad? Explain to students that they will learn mathematics by analyzing what they hear on the radio and will write their own radio commercials on the basis of patterns that they find in radio commercials.

Structurlng the Investigation

1. Divide the class into teams of three or four students. Explain that each team will collect data by listening to a radio. Assign a variety of stations to monitor so that each team listens to a different radio station. Assigned stations must represent a variety of formats, including FM and AM as well as music and "talk radio."

2. Distribute a copy of the reproducible page to all students. To collect data, students will need access to a radio for one hour as an "outside of class" assignment. Explain that they should turn on the radio every five minutes for an hour, just long enough to determine what is on the air, until they have recorded twelve tally marks on their reproducible pages. Each time they turn on the radio, they are to note whether they are hearing a commercial or a public-service announcement or are listening to something else, such as music, news, or conversation. Some students may prefer to listen to the assigned station for the entire hour, noting at five-minute intervals whether they are listening to a commercial.

3. Have students bring in their results and reconvene in their teams. Students on each team should combine their data so that they have a count of how many times out of the total sample the station was running commercials. Ask students to complete the items on the reproducible page that require recording the proportion of time spent on commercials and on other material to be written as fractions in simplest form.

4. Have each student complete a circle graph of what he or she has heard on the radio. Some students may need help to convert proportions to degrees of a circle. Other students may prefer to generate their circle graphs with computer software. Since this investigation focuses on the categories of "commercials" and "other," be certain that graphs contain two sectors forming the complete circle.

5. When students have completed the questions and graphs, discuss the variation in results. For example, teams can display their circle graphs and make comparisons between FM and AM. …