These are questions about the Speed of Sound. Please provide an explanation for

Question

These are questions about the Speed of Sound. Please provide an explanation for each part. Thank you so much for your kind assistance. You can estimate your distance from a bolt of lightning by counting the seconds between seeing the flash and hearing the thunder, and then dividing by three to obtain the approximate distance in kilometers 1.) a.) Explain why this trick works. (Why "three?) b.) This trick assumes that you see the lightning right when it occurs, and just need to wait for the sound to arrive. If this is expected to be accurate, what must this mean about the speed of light? c.) How could this trick be tweaked to give a similar no-calculator "rule of thumb" for the approximate distance in miles? What number should be used instead of "three"? (Note: 1 mi-1609 m)

Explanation / Answer

(a)

We use this trick (i.e.,number of seconds until you hear thunder from lightening divide it by 3) when we are Calculate the distance from lightning kilometers.

Sound travels one kilometre for every three seconds. Therefore, if you want to find out how far you are from lightning, divide the number of seconds by 3 if you want the answer in kilometres. The delay between when you see lightning and when you hear thunder occurs because sound travels much more slowly than light.

Example: Let's say you counted 18 seconds. To find your distance from the lightning in kilometers, divide 18 by 3 to get 6 kilometres.

(b)

This technique is called the "flash-to-bang" method, and it can keep you safe during rainy summer weather. This method is based on the fact that light travels much faster than sound through the atmosphere: Light travels at 186,291 miles per second (299,800 km/s), whereas the speed of sound is only about 1,088 feet per second (332 meters per second), depending on air temperature.

(c)

Sound travels one mile every five seconds and one kilometre every three seconds. Therefore, if you want to find out how far you are from lightning, divide the number of seconds by 5 if you want the answer in miles and divide it by 3 if you want the answer in kilometres. The delay between when you see lightning and when you hear thunder occurs because sound travels much more slowly than light.

Example:

Let's say you counted 18 seconds. To find your distance from the lightning in miles, divide 18 by 5 to get 3.6 miles. To find your distance from the lightning in kilometres, divide 18 by 3 to get 6 kilometres.

Though you won't be able to get a completely accurate result because the weather may vary in temperature and humidity, which will slightly affect the speed of sound, this is a good way to estimate how far you are from the lightning.

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