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What are speeds of sound and of light . We are doing research on lightning and thunder .
- Holly Harper (age 9)
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.
(republished on 07/29/06)
Follow-Up #1: light/sound time lag
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
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.
(published on 07/10/07)
Follow-Up #2: light and sound
how do we know light travels quicker than sound
- katrina (age 12)
When there's a big lightning strike, you see it first, then hear it a little later.
(published on 01/26/09)
Follow-up on this answer.