Speed Of Sound

The speed of sound is a very relative term that depends on many different conditions and variables. Likewise, many different variables went into trying to move faster than the speed of sound. This article will attempt to educate you on the history of the speed of sound, sound barriers, calculating the speed of sound, trivia, and any other important facts that you should know about the speed of sound.

History

Chuck Yeager became the first man to break the sound barrier in 1947 over the the airspace of Edwards Air Force Base. Yeager flew the first ever Bell XS-1 rocket-propelled research aircraft that was later used to create the aircraft that takes the space shuttle high enough into the atmosphere to fly into space. Scientists and enginners already knew that objects could travel faster than the speed of sound because bullets and cannon balls had been doing it for years. The trick to making an aircraft travel faster than the speed of sound was simply designing the aircraft to have enough power to reach those speeds and designing the wings to be able to sustain the shock waves that are generated when an object reaches supersonic speeds.

Calculating the Speed of Sound

Before you can calculate the speed of sound, you should know what exactly a sound is. Sound is the result of a vibration moving through an elastic medium (a medium can be anything including air, water, land, space, or any other object or surrounding you can think of). Think of a slinky being pulled apart and pushed back together as it makes its way down a set of stairs. That’s basically what sound is. In order to calculate the speed of sound, you must first figure out what kind of surface it’s moving across, the speed of the object that created it, the density of the medium, the temperature of the medium, and the compressibility of the medium. The formula for calculating the speed of sound is the square root of the stiffness of a medium divided by the density of that medium. The speed of sound is relative, however, and can differ drastically in air, water, gas, and plasma.

Sound Barrier

Contrary to popular belief, there are actually several sound barriers; not just one. Generally, “the sound barrier” refers to the initial change between transonic speed and supersonic speed. When an aircraft moves fast enough to exceed the speed at which air compresses, the aircraft is said to “break” the sound barrier, resulting in a loud, booming noise and a white shield-like cloud of water droplets that make the aircraft look as though it is emerging from a white wormhole. Aircraft not only “break” the sound barrier when going from transonic to supersonic, but also from supersonic to transonic. When a space shuttle comes in for a landing, it breaks many different sound barriers along the way. When an aircraft flies at the speed of sound, it is said to travel at Mach 1. If the aircraft travels at twice the speed of sound, it is referred to as Mach 2. If it travels at three times the speed of sound, it is called Mach 3, and so on.

Fun Facts

Below are some fun facts about the speed of sound that might actually surprise you.

1. Ever since the invention of the musket, firearms have routinely created sonic booms as the bullet leaves the chamber which is the loud noise that you hear when a gun is fired.

2. It was once common knowledge that if an aircraft exceeded the speed of sound, it would explode. It was also believed that traveling at such high speeds would result in changes to the laws of physics.

3. Some bull whips are able to move fast enough to break the speed of sound, which is why you hear a loud cracking noise.

4. Paleobiologists who have constructed computer representations of certain types of dinosaurs believe that these animals could crack their tails through the air so fast that it would break the sound barrier in order to intimidate and scare off opponents.

5. Chuck Yeager was the first person to break the speed of sound but the Air Force originally asked the famous and highly respect test pilot, Slick Gooden, to do it. Gooden said that such a feat would be a very dangerous task and he demanded a $150,000 bonus (which was a lot more money at the time), while Yeager claimed that the Air Force was already paying him to be a test pilot and performed the stunt for free.

6. The plane that was used to first break the sound barrier was named Glorious Glennis in honor of Chuck Yeager’s wife.

7. Because Chuck Yeager broke the sound barrier during the Cold War, the event was not released to the public for nearly a year so that the Soviets wouldn’t know that America had the technology.

8. Scott Crossfield broke the airspeed record by traveling at Mach 2 but Chuck Yeager soon retook the record by flying at Mach 2.4.

9. Balloons can startle anyone when they pop because the air rushing out of the hole in a balloon causes the rubber to exponentially expand. This expanding hole actually moves faster than the air outside of the balloon and results in a sonic boom.

10. The speed of sound in water is nearly five times faster than the speed of sound in air.