Learn more physics!
Q:
What are speeds of sound and of light . We are doing research on lightning and thunder .
- Holly Harper (age 9)
Gladstone
A:
Holly,
The speed of sound through air is about 340 meters per second. (The
speed of sound in water is about 4 times faster than this). The speed
of light in air is about 300 million meters per second.
Mats
(published on 10/22/2007)
Follow-Up #1: light/sound time lag
Q:
If you see a flash of light and it takes 5 seconds before you here the noise how far is that flash away from you
- Anonymous
Hendersonville NC
A:
The distance depends on the speed of sound in air. This speed varies slightly depending on the temperature, pressure and humidity. For ’back of the envelope’ calculations you can take
V = 340 km/sec. The distance-speed-time relationship is d = V*t. So plugging in the numbers you get 1700 meters, a tad over one mile.
Lee H
(published on 07/10/07)
Follow-Up #2: light and sound
Q:
how do we know light travels quicker than sound
- katrina (age 12)
liverpool
A:
When there's a big lightning strike, you see it first, then hear it a little later.
Mike W.
(published on 01/26/09)
Follow-up on this answer.
