How to Find the Distance to Thunderstorms and Fireworks

Learn some fun facts about fireworks and thunderstorms, and find out how you can use math to quickly and easily estimate how far away they are from you. 

Jason Marshall, PhD,
July 3, 2015
Episode #111

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Fun Facts About Thunderstorms

Have you ever wondered where thunder comes from? No, I don’t just mean knowing that it comes from thunderstorms, I mean actually knowing why thunderstorms produce thunder in the first place. I’ll leave it to Everyday Einstein to explain all the detailed science, but the basic idea behind the origin of thunder is pretty simple. In a nutshell, thunder comes from 100-million Volt bolts of lightning (that’s huge, by the way…your household electrical system runs at a measly 120 Volts). These lightning bolts quickly heat the air surrounding them up to tens of thousands of degrees Fahrenheit (which causes the air to “expand”), and the subsequent cooling of the air (which causes it to “contract”) results in the production of sound waves—aka, thunder. Voilà!

Speed of Sound vs. Speed of Light

Now that we understand a bit about why fireworks and thunderstorms produce their spectacular sights and sounds, let’s see what we can do with this knowledge. The first thing we need to understand is how light and sound travel through air. In particular, the fact that light and sound travel at very, very different speeds. More precisely, a sound wave (which is just air molecules progressively bumping into each other on their way to bumping into your eardrum) travels through air at about 770 miles per hour (although the precise value depends a bit on things like humidity, altitude, and temperature).

While that’s definitely faster than your car or even a passenger jet, it’s tortoise-slow compared to light waves that travel about 670,000,000 miles per hour! Just to make this remarkable difference clear, light travels about 870,000 times faster than sound…which means that in the time it takes light to travel from Los Angeles to New York, a sound wave will travel only about 15 feet.

In the time it takes light to travel from Los Angeles to New York, a sound wave will travel only 15 feet.


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