What exactly causes thunder?

Question

And i dont mean "its lightning duh" i mean in a scientific manner please. I'm just curious as to what is causing that noise. Or if its an exothermic reaction and the noise thunder is just a byproduct. I'd like a scientific answer with a reputable source as well. Thanks.

Answer 1

Best Answer - Chosen by Asker

Lightning is, as you know, electricity rushing from cloud to cloud or from cloud to ground. A very large current momentarily rushes from a cloud to ground. (Actually, some physicists believe the lightning propagates from the ground up to a cloud. In any case, current flows, for a brief second.)

It's not easy to get current to flow across air, as you might guess--after all, you don't get shocked every time you walk by a light socket. So air has a high resistance. By Ohm's Law, V=IR, a large current across a high resistance requires an INSANE voltage. And by P = IV, it can be shown that the lightning generates a huge amount of power.

Not all of that power goes into the flash. The resistance provided by the air has to drop the lightning's voltage down near 0 by the time it gets to ground. So the power is absorbed by the resistance of the air, and is turned immediately into heat, in much the same way as 110V line power creates resistance heating in a toaster or hair dryer.

Treating air as an ideal gas (not a bad assumption in this case), you know that Pv=RT; temperature is proportional to pressure times volume. So if the temperature goes way up suddenly, and volume remains relatively stable, then pressure must go way up. This is precisely what happens. The air heats up and expands rapidly, creating a big, powerful pressure wave.

What is sound? Nothing but pressure waves.

In short: Lightning travels through air, air has a resistance to electrical current. The electrical power in lightning creates resistance heating in the air, which expands and creates an immense pressure wave, which our ears pick up and interpret as sound.

Clear enough?

Source(s):

Natural childhood science prodigy refined by training as an engineering student.

Asker's Rating:

Asker's Comment:

Wow, incredible answer, everyone else had some great ones too, but this was just very very informative, it's what i was looking for. Thanks!

Answer 2

A bolt of lightning will burn the air in a microsecond. Then the air has to rush back in to fill that space. That is what thunder is. The thunder is a byproduct of the electrical stroke.

Source(s):

High School physics classes, sorry this is pretty basic information.

Answer 3

Thunder is caused by lightning- right. The sound is made as the air around the lightning bolt heats & then cools. The air by a strike of lightning is heated at a high degrees.When the air cools down, it causes a shock wave to occur (aka) thunder.

Source(s):

I love science. Constantly studying it.

Answer 4

a build up of energy

Answer 5

Lightning only causes thunder.When a bomb explodes, air around expands very rapidly creating almost a vacuum near it.Immediately after the explosion, air suddenly contracts trying to occupy the empty space.In similar coditions shock waves are produced which create the noise.Similarly the lightning arc produces enormous heat which makes the nearby air expand suddenly and contract immediately after that creating the above mentioned shock waves resulting in a loud noise.

Answer 6

When a cold air front and a warm air front meet you get thunder. ...



Thunderstorms can occur just about any time of the year and any where. Severe thunderstorms usually will occur in the spring and fall because there are more cold and warm air fronts than at any other time of the year. Frontal thunderstorms happen when cold air is more dense than warm air. When a cold front reaches a warm air mass, it quickly makes the warm air rise, making the conditions for severe weather in the troposphere.This situation in the trosphere can cause winds of up to 58 miles per hour, large hail, and even tornadoes. A frontal thunderstorm looks like a thick line of thick cumulonimbus clouds.


http://library.thinkquest.org/CR0212082/…


Had to go look it up just to be sure i was remembering correctly what I learned from science class.

Answer 7

I was told because god is mad

Source(s):

the bible

Answer 8

Actually thunder is the clapping of clouds coming together after they are split through by lightening. check out this web site www.howstuffworks.com, I love this site for finding out how things are done, work or created...

Answer 9

I don't have a source, but I was watching something on discovery or national geographic yesterday that said the same thing. Lightning is hotter than the surface of the sun. When you heat something, like air, it expands. It is heated so rapidly that the expansion occurs above the speed of sound, breaking the sound barrier and creating a sonic boom. The reason it sometimes rumbles is when the lightening is far away, it echos and reverberates off of the ground, buildings, etc. If lightening ever hits close by, it sounds like a shotgun going off next to your ear, with no echos or delay. The delay is simply caused by the speed of sound (roughly 700 mph) and the distance between you and the lightening strike itself.

Answer 10

thunder is the sound of lighting. light moves faster then sound, so thats why you see lighting before you hear thunder.

Answer 11

nature du

Answer 12

whenever I'm mad it thunders....

Answer 13

Lightning bolts are extremely hot, with temperatures of 30,000 to 50,000 degrees F. That's hotter than the surface of the sun! When the bolt suddenly heats the air around it to such an extreme, the air instantly expands, sending out a vibration or shock wave we hear as an explosion of sound. This is thunder. If you are near the stroke of lightning you’ll hear thunder as one sharp crack. When lightning is far away, thunder sounds more like a low rumble as the sound waves reflect and echo off hillsides, buildings and trees. Depending on wind direction and temperature, you may hear thunder for up to fifteen or twenty miles.

Source(s):

www.wxdude.com/page5.html

Answer 14

The electricity from positive and negative charges: from clouds to surface, clouds to other clouds, etc. that break the sound bearier that it causes that loud roar, "thunder."

Answer 15

the clouds get really angry at eachother and they beat eachother up because one said to the other, "Im bigger and better than you are".

Answer 16

It is lightning breaking the sound barrier.

Answer 17

Thunder IS caused by lightning, which is essentially a stream of electrons flowing between or within clouds, or between a cloud and the ground. The air surrounding the electron stream is heated to as hot as 50,000 degrees Farhenheit, which is three times hotter than the surface of the sun. As the superheated air cools it produces a resonating tube of partial vacuum surrounding the lightning's path. The nearby air rapidly expands and contracts. This causes the column to vibrate like a tubular drum head and produces a tremendous crack. As the vibrations gradually die out, the sound echoes and reverberates, generating the rumbling we call thunder. We can hear the thundering booms 10 miles or more distant from the lightning that caused it

Source(s):

http://www.sciam.com/askexpert_question.…

Answer 18

Thunder is caused by lightning. The sound is made as the air around the lightning bolt rapidly heats and cools. The air around a lightning strike is heated to 50,000 degrees Fahrenheit (27,500 C), as the air cools it causes a shock wave to occur known as thunder. The closer the lightning is, the louder the clap of thunder will be.

Source(s):

http://www.wisegeek.com/what-causes-thun…