Ondo for learning
Teachers, why not use Ondo as a fun and practical way to explore the science of sound? These are just a few of the learning objectives you could explore:
- Sound is a wave that travels through air at the Speed of Sound
- The Speed of Sound varies with the temperature of air
- Speed (or velocity) is distance divided by time
- How to build an Acoustic Thermometer
Download our lesson planner here.
Design and Make project
Why not design your own device for holding the ear piece and microphone? Perhaps it could also be used as a convenient carrying case for the headset? We are sure that you can come up with better designs than our elastic bands.
Download our design guide here.
The science behind Ondo
Acoustic thermometers rely on the principle that as air temperature varies, its density varies. The change in air density causes the speed of sound to vary according to the formula:
…where ‘t’ is the temperature in degrees Celsius.
The speed of sound can be measured by timing how long it takes for a sound to travel a known distance, ‘d’ between two points; typically, a speaker (the source of the sound) and a microphone (the receiver of the sound). The speed can then be calculated in the usual way by dividing the distance by the time to cross the distance.
How Ondo works
Ondo generates a test sound that is played on the right earpiece speaker. This test sound is then received by the headset microphone after travelling distance (d). The transit time between the speaker and the microphone is then precisely measured to less than one millionth of a second, enabling the speed of sound and hence air temperature to be calculated.
Further resources
The following links provide some additional background resources on the theory of sound:
- https://www.bbc.com/education/guides/z8d2mp3/revision/3
- https://www.texasgateway.org/resource/141-speed-sound-frequency-and-wavelength
These links provide some additional information on acoustic thermometry: