Making a Stethoscope

INTRODUCTION

Doctors use stethoscopes to listen to people’s heartbeats. As the heart beats, it causes the stethoscope to vibrate. These vibrations are transmitted as sound to the doctor’s ears. A stethoscope amplifies the sound (i.e. it increases the loudness of the sound) so the doctor can clearly hear the faint heartbeats.

MATERIALS

• 2 plastic funnels
• 20 in. (50 cm) of flexible plastic tubing

WHAT TO DO

1. Push the narrow ends of two funnels into the open ends of the plastic tubing. If the tubing is too narrow, warm the ends near a source of heat to soften the plastic.
2. Ask a friend to hold one funnel over his or her chest. Place the other funnel over your ear and listen carefully. Can you hear your friend’s heart beating?

QUESTIONS

1. How do you think your stethoscope works?
2. How is your apparatus like a real stethoscope?
3. Can you think of any other useful applications for this device?

SOURCE

"SOUND: Science Activities." Graham Peacock, Wayland Publishers, Ltd., 1993, p. 23.

© S. Olesik, WOW Project, Ohio State University, 2000.