# Speed Of Light vs. Speed Of Sound

• By reComparison Contributor
• 12
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## Difference between Speed Of Light and Speed Of Sound

Most people know that the speed of light is much faster than the speed of sound, and that the speed of sound is measured by the Mach scale. Aside from that however, few people are aware of the key characteristics of each and what makes them so distinct. This comparison article should clear up a few things.

 Photo by włodi

## Definition

The speed of light is a physical constant that is essential to study in many areas of physics, and it is typically denoted by “c”. In this case, the “c” stands for the speed that light and electromagnetic radiation always travel at in a vacuum, regardless of the direction of the source or the observer's inertial frame. Its value is measured at 299,792,458 meters per second.

Speed of sound on the other hand, is the distance that sound travels through an elastic medium. In dry air with a temperature of 20 °C, the speed of sound is measured at 343.2 meters per second. This translates to 1,236 kilometers per hour, or about one kilometer every three seconds.

## How They Are Measured

As mentioned previously, the speed of light is denoted by a “c”, which stands for "constant". "C" is sometimes used to refer to the speed of waves in a certain medium, while “c0” is used to refer to the speed of light in vacuum.

In certain studies of physics wherein the speed of light is an essential measurement, "c" is often assigned a value of "1". In such cases, the speed of light is no longer a valid measurement in physics terms, since multiplying or dividing a figure by 1 does not affect the result.

The speed of sound is measured as a Mach number, which is one of the most important quantities in aerodynamics. Mach is simply the ratio of air speed to the local speed of sound. It is interesting to note that Mach is considered to be a function of temperature at high altitudes. This is because certain equipment on the aircraft relies on air pressure as indicated by the temperature.

## Implications

The concept of the speed of light has numerous important implications for different sciences and technologies. Microprocessors, for instance, work on the assumption that the speed of light is the absolute fastest speed that signals can be sent, which puts a theoretical cap on how fast they can go. The speed of light has also given scientists increased opportunities to measure vast distances into space.

As for the speed of sound, it is most affected at ground level by temperature. Temperature and the speed of sound typically decrease the higher up into the atmosphere you go, and sound is then refracted away from people on the ground. This basically creates a quiet zone a short distance away from the source of the sound.

## Similarities and Differences

Speed of light

• A physical constant that is essential study in many areas of physics
• “C” stands for the speed that light and electromagnetic radiation always travel at in a vacuum
• Measured at 299,792,458 meters per second

Speed of sound

• The distance that sound travels through an elastic medium
• Measured at 343.2 meters per second

Which speed is faster?
• Speed Of Light
• Speed Of Sound

### Discuss It: 12

• Wenda Zonnefeld wrote on July 2011

I am searching for how our brain percieves this difference. Everyone's analogies of this topic uses lightning and thunder as a comparison. There are too many variables thrown in for this comparison (temperature,altitude, wind- as well as direction). We percieve pictures streamed as slow as 24 frames a second as "moving" (I'm referring to film, movies). The skill to sync sound with picture has been extremely under valued. I would like to find the difference between the human brain's perception of time compared with light and sound.

• kendall wrote on November 2019

I agree.

ya doof

• kendall wrote on November 2019

**** you

• bob wrote on April 2014

where dja learn that

• bob wrote on April 2014

preskool?

so stoopid

gawd, ur oll retartid

• chris wrote on May 2014

What differences are you looking for?lighting flashes and it takes time for the sound to reach your eardrum.

Or lightning flashes and because of the distance, you never hear a sound; hence, the mythical legend of "heat lightning" lives on.

• Jade wrote on January 2015

Basicly speed of light is faster than the speed of sound pretty god damn amazing :D luv it!

• kendall wrote on November 2019

doesn't help shoot.