# Of Roller Coasters and Song

### Maxine Edwards and Mary Teal

The Center for Advancement of Teaching

###

Of Roller Coasters and Song

Lesson Plan

Algebra 1 Level

**Objective:**
The student will be able to plot a sinusoidal curve representing the pressure vs. time relationship of sound.

**Stage 1:** Discuss the motion found in previous rebounding experiment (P2). Discuss the other times students have seen representations of sine-like graphs - ex. heart monitors, sound waves.

**Stage 2:** Group activity
1) Take students to an enclosed stairwell.
2) Have one student count the number of stairs from the top to the first landing.
3) Place** SLINKY** (the slinky can be any variety but it must be at least 8 cm in diameter and the concentric rings must be at least .5 cm wide) at the top of the stairs and release. SLINKY should proceed down the stairs one at a time.
4) Have students observe the action of the** SLINKY.**
5) Return to room, where students will individually graph (approximation of activity) their observations on a single quadrant graph. Tell students to label the horizontal axis as the number of stairs and the vertical axis as the height of the SLINKY motion. You will want to remind students that they will not have exact numerical values for the height, but that they are to draw their observations using their best guess.

**Stage 3:** Discuss student graphs. Have students draw their graphs for entire class discussion. Have students look for a repeated pattern and /or similarities among the graphs.
Note: At this point all students should be helped to discover that the **SLINKY **should have had consistent heights and that the differences are due to the stairs not being level.

**Stage 4:** Conduct experiment.

**Stage 5:** Compare student graphs of both tones. Discuss which graphs matched and what needed to be changed in order to make the sound frequencies match.
Collect each group frequency and period to make a single quadrant graph.
Discuss changes in the tone represented by each.
Give students a frequency value to predict how that value tone should compare to the others represented. Students could also predict the pitch of a tone given the frequency.

*Developed by:*

Maxine Edwards and Mary Teal

Butler High School
Matthews, NC

additional help from:

Neal Farley

Independence High School

Charlotte, NC