Vibrations and Waves for the Health Science Major

Mark W. Plano Clark

Doane College

February 2002Supported in part by NSF DUE0088712

Overview• Develop an introductory physics curriculum

• Who: Health science majors

• Why: Students see little relevance to goals

• What: – Intrinsically motivating activities– interactive engagement– Problem solving strategy– Multimedia– Mathematical modeling

Speech and Hearing

• Base the physics on the human body - the hook!

• Physics topics in this module: vibrations, waves, standing waves, Hooke’s Law, pressure, fluid flow, Bernoulli's principle

• Emphasize mathematical modeling, problem solving, multimedia

Motivation - The hook!

• Thanks Chris Wentworth and his nose!

Exploration

• How does the human vocal system produce such amazing sounds?– Feel your throat while making the following

sounds• make soft sounds, loud sounds

• sing a high note, a low note

• say aaah, say eeeee

Invention

• Study the properties of a simple larynx/pharynx model

• Make a loud sound, a soft sound

• Produce a high pitched sound, a low one

• Produce the same pitch with different levels of loudness

• What’s happening…?

More Multimedia

• High speed digital video (DV) of vocal folds model

• Follow one point along the edge of the “vocal folds” - vibration

• Can we produce a simple mathematical model that approximates the motion?

Vibrations - The Ruler

Mathematical Model - SHO?

• Repetitive motion• Collect data using VideoPoint - more later!• Model the data in Excel• Introduce the simple harmonic oscillator

– x(t) = Asin(2ft)• How well did we do?

Vibrating Ruler

-0.1

-0.05

0

0.05

0.1

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Time (s)

Am

pli

tud

e (

m)

Conclusions - so far….

• Students definitely enjoyed manipulating the larynx model!

• Many experiments are standard physics experiments but more personal

• Investigators (well some) enjoyed discovering human applications