My friends are always saying this. When they see lightning they will start counting, when they hear thunder they say that the lightning bolt was as many seconds as they counted away. Is this acualy accurate?
2006-07-06 05:17:37 · 7 answers · asked by j_ririe20 1 in Science & Mathematics ➔ Weather
Lightning is an electrical discharge between the Earth and a cloud (in actually fact the initial lightning strike goes FROM the Earth to the cloud, but I won't go into the technicalities now). The lightning strike does two main things as far as the observer is concerned:
1. it creates a flash of light
2. the electrical energy is so powerful that in simple terms it fries the air it's passing through, causing an explosion we hear as thunder.
If you were directly under the point the lightning strikes then you would hear the thunder and see the flash at the same instant.
The difference in time as you are further and further away is due to the different speeds that light and sound travel.
Light travels at 186,000 miles per second (yep thats second - so pretty quick!)
Sound travels at about 760 miles per hour through the atmosphere, which is pretty sluggish in comparison.
The result is that when lightning strikes we see the flash of light almost instantaneously but the sound takes longer to reach us:-
760 miles in 60 minutes
= 76 miles in 6 minutes
= 76 miles in 360 seconds
= 7.6 miles in 36 seconds
= 1 mile in 4.736 seconds
In round figures this means that for every 5 seconds the sound travels a mile.
So if you start counting when you see a lightning flash you can judge how far away the strike was:-
5 seconds = 1 mile
10 seconds = 2 miles
15 seconds = 3 miles etc etc
Incidentally counting the seconds is an excellent way of teaching small children not to be afraid of thunderstorms - they get so involved in counting they forget to be scared!
2006-07-06 05:39:47 · answer #1 · answered by Anonymous · 3⤊ 1⤋
Sound travels about 700mph (based on speed at altitude of the clouds and on surface averaged). This would be 700 miles per 60 minutes; = about 12 miles per minute, =0.19 or about .2 = 1/5 mile per second. So the lightning strikes and the light arrives immediately (speed of light). Then for every 5 seconds that pass before the thunder arrives the bold is 1 mile away.
2006-07-06 19:12:06 · answer #2 · answered by The Mog 3 · 0⤊ 0⤋
It's about 5 seconds to 1 mile. As an approximate rule, you can assume you see the light from the storm almost immediately, the sound of the thunder travels at about 1,100 feet per second. Since a mile is 5,280 feet, you can count about 5 seconds for each mile.
Whenever you hear thunder you should make sure you're someplace safe.
2006-07-06 12:27:29 · answer #3 · answered by benconsult 2 · 0⤊ 0⤋
Count (one per second) from when the lightning strikes to when the thunder rolls, then divide by 5. That will tell you how far (in miles) the lightning strikes
x=y/5
x = Miles
y = number of seconds
2006-07-06 17:47:10 · answer #4 · answered by Anonymous · 0⤊ 0⤋
In a thunderstorm, the speed of sound is around 1000 ft/min. So sound travels around 1 mile every 5 seconds.
2006-07-06 13:06:14 · answer #5 · answered by Juan C 1 · 0⤊ 0⤋
correct...just multiply the no. of seconds between the time u see the lightning and the time u hear it by 330 metres. the final ans is the approx distance between u and the place lightning occured..any doubt?
2006-07-06 12:23:50 · answer #6 · answered by Anonymous · 0⤊ 0⤋
nope, but it's close enough to keep the panic down
2006-07-06 12:56:43 · answer #7 · answered by shiara_blade 6 · 0⤊ 0⤋