Measuring Distance with Sound Waves
Students learn about sound waves and use them to measure distances between objects. They explore how engineers incorporate ultrasound waves into medical sonogram devices and ocean sonar equipment. Students learn about properties, sources and applications of three types of sound waves, known as the infra-, audible- and ultra-sound frequency ranges. They use ultrasound waves to measure distances and understand how ultrasonic sensors are engineered.
Two applications that use sound waves to measure distance: A sonogram uses high-frequency ultrasound to make an image of a fetus (left), and a ship's sonar sensor uses ultrasound signals to scan the ocean floor (middle). A student uses LEGO® MINDSTORMS® robot ultrasonic sensor to measure distance (right).Copyright (left to right) 2004 San Pullara, Wikipedia; Natural Environment Research Council; 2012 Irina Igel, Polytechnic Institute of NYU http://en.wikipedia.org/wiki/File:Baby_in_ultrasound.jpg http://www.antarctica.ac.uk/press/images/press/854/swath_illustration_final.jpg
Sounds are everywhere in our daily lives. While we easily and frequently control the sound volume of TVs and music players, we can also use sound's other properties to determine the health and gender of growing fetuses or to locate sunken ships on the ocean floor. In fact, sonograms and sonar devices take advantage of a very simple physics and math relationship that enables sound waves to be used as a tool to calculate distances (distance = time x velocity).
After this activity, students should be able to:
- Describe how sound waves can be used to measure the distance between objects.
- Give examples of ultrasound applications in technology and everyday life.
- Convert units, such as seconds into microseconds.
- Identify the frequency range for human hearing, known as the audible range.