why does thunder last longer than the lightning that produced it?

Question

Most people answer that it is because sound travels so much slower than light. That explains the delay, not the duration. I belive we can tell a lot about the shape and length of the lightning bolt by the duration and character of the sound produced. Faint to loud and then faint again might mean horizontal lightning where the observer is more or less in the middle. Loud and then trailing off might mean it was angled away from the observer. Anyway, I have no scientific proof of any of this. =)

Answer 1

There is a great article to read on this, from How Stuff Works. Its under "How Lightning Works", but it talks about both lightning and thunder. My students got a lot out of it.

Answer 2

You're hearing the thunder that was produced from each point along the length of the lighting bolt. Since each point is not the same distance, some of the noise reaches you faster than others. And since the lighting is a continuous path, you can't distinguish the different points, and just hear a rolling thunder.

But, you can't tell much about the shape and length of the bolt from the sound of the thunder, because you're also hearing echos, as the thunder bounces off buildings, some of which may be a mile or two in the other direction.

Answer 3

It is because sound travels slower than light. Not only does this produce the delay, but also the duration. What takes 1 second to see may take 15 seconds to hear. Since the sound waves travel slower, they are also more disbursed and spread out over a wider range. Your theory of sound analysis to determine the type of lightening is interesting and, I think, plausible. I would contact some local colleges, preferably those that offer courses in meteorology, or perhaps the meteorologist at the local TV station and ask if this has ever been studied.

Answer 4

It has everything to do with the difference in the way sound and light travel. An electrical discharge happens in a fraction of a second. And once completed that’s all we see of it because the light dissipates at 186,000 miles per second. So although the light from a lightning bolt is reflected off various objects, it travels and dissipates so fast that we still only see it for a fraction of a second. The thunder on the other hand travels at the speed of sound, which is affected by a number of variables (humidity, altitude, barometric pressure etc.). Generally it is around 700 miles per hour but nevertheless much, much slower than the speed of light. Like the light, sound from the thunder is reflected off of various objects but it happens so much slower than the light, we continue to hear the reflections. Think echoes.

Answer 5

My answer of course as many others I'm sure have answered is the plane old fact of how light travels faster than sound. If i may use and example. Have you ever gone into your bedroom or in other room of your house and turned the light on to see a light bulb blow out? If so then you have noticed that when you turn the switch the light immediately goes out but you can hear the "Pop" sound at least 3 seconds after. Thus the light in the bulb is the lighttning and thus the sound of the lbulb breaking is the thunder. This is the best explanation i can think of. Hope it works. =-)

Answer 6

Thunder is the sound...lightning is the light. There can be a few answers to your question.

Visible light travels differently than sound. Yes light is faster, and there's a delay until the thunder. But imagine how sound waves are bouncing off of any object, whether it be the ground or building. The light does that but at a faster speed.

Not only do light and sound travel differently and at different speeds, but the wavelengths affect how you notice it.

Answer 7

The reason that thunder lasts so much longer than lightning is becasue the sound waves of thunder are being bent and redirected, echoing off of millions of individual raindrops. To support this, think of the last time you heard thunder from a very close lightning strike. The initial BOOM is very short in duration, but then you can hear several seconds of reverberation... this is all echo. I hope this helps

Answer 8

you would think that the sound of thunder travels slower than light, which is true, but thunder is caused by the lightning super-heating of the air to as high as 50,000+ degrees, thus rapidly expanding the air. the best way for me to describe the way air returns via cooling would be to have you do this experiment. in a swimming pool, take your hand, and as fast and as hard as you can, do a karate chop on the water, from the surface downward into the water. watch as the water collaspes back together. the same principle works as the lightning bolt superheats the air, and the air rushes back, thus creating the sound of thunder. the hotter the area of lightning, is the longer it takes the air to cool. thus the delayed sounds of thunder rumbling. in cloud to cloud lightning you tend to hear what we call rolling thunder. that is when lightning travels from one cloud to another and since sound travels slower than light, the thunder rolls along as the air collaspes behind the shot of lightning.

Answer 9

Maybe because lightning is a flash of light, whereas thunder is the expansion of air caused by the heat of the lightning. And energy passes through air slower than a flash of light, so it lasts longer.

I'm not too sure by the way :S

Answer 10

This happens because light speed is greater thant the sound speed on air. So when the lightning descends from the sky it hits the ground, the sound waves reach your ears far after the lightning disappears. And there is reverberation...