Speed Of Sound In Various Substances
Speed of Sound: The speed of sound is the rate at which sound travels from the sound producing body of our ears. The speed of sound depends on the
- Nature of Material: (or medium) through which it travels. Speed of sound in air is 344 m/s.
- Temperature: As the temperature increases the speed of sound in air increases.
- Humidity of Air: Sound travel first in humid air.
Sound waves travel at different speeds in different substances. Table gives the speed of sound in various substances. The speed of sound depends on various factors like temperature, nature, and physical state of the substance, etc. For example, the speed of sound in air is about 330 m/s at 0°C and 346 m/s at room temperature. Also notice from Table that sound waves travel fastest in solids and slowest in gases.
Substance | Speed (m/s) |
Air | 346 |
Water | 1498 |
Mercury | 1452 |
Glass | 5000 |
| Aluminium | 5000 |
| Iron | 5000 |
| Diamond | 12,000 |
Activity
Aim: To show that sound travels more efficiently through solids.
Materials needed: A long table (dining table/long school bench).
Method:
- Make a friend (A) sit under the table and the other (B) to put his ear to the table top.
- Now scratch the underside of the table very gently.
- Find out which one of your friends heard you scratching the table.
Observation: You will find that the friend who put his ear to the table top (B) would have heard the sound and the other friend (A) would not have heard it.
Conclusion: The sound you made travelled through the table (solid), but was not strong enough to travel through air. If it had travelled through air, friend A would have heard it before friend B because he/she was closer to the sound.