Earlier in the week, The Phoenix Auto Glass blog shared how subwoofers have actually been known to shatter a car windshield and the science behind how that happens. Our article today will investigate a sonic boom that was reported to have broken the windshields of 84 cars. We will explain how this phenomenon can in fact shatter glass.
In October of 2011, residents of the Lashbrooke subdivision in Louisville, Tennessee were buzzing about mysterious booms that were shaking the neighborhood. Louisville resident, Andy Wombold, described the event as he remembered it.
“[It is] scary-loud; [It is] loud enough that it makes your heart stop for a second,” said Andy Wombold. ”It sounds like a shotgun or an explosion of some kind. Last Monday, about a week and a half ago, it was around 3 a.m. and it was, ‘Pow!’ All the sudden we heard a loud explosion. It sounded like it came from inside our house. It shook the walls; It shook the floor; It shook the ceiling,” said Wombold. “We thought maybe a gas line had exploded and maybe our house was going to blow up. We thought it was really serious,” said Wombold.
“It was like lightning struck directly beside the house,” said neighbor Dwayne Jones. ”I jumped out of bed and ran outside. Then I saw a clear sky full of stars and knew it [was not] lightning. The ground was still shaking for a little bit. It was like a big sonic boom. Just the whole house shakes. I never heard anything like it.”
Stricken with fear by the unidentified noise, many residents called the emergency dispatcher. Still, the noise remained a mystery. Investigations began but yielded no conclusions. The local rock quarries confirmed there were no blasting operations. A Tennessee National Guard spokesperson confirmed that there were no military operations in that area that could be a possible culprit. T-DOT reported there were no constructions projects in the area that might explain the noise. TVA confirmed there had been no issues with the power lines near the neighborhood. The boom was reported to continue for several days.
”It was like they would get a little weaker as the days went by, but it was still really jarring. You generally heard one big boom and then a bunch of aftershocks in quick succession. I [do not] know if it was an echo off the river or what,” said Wombold.
While there were no reports of people injured from this incident, there were reports of 84 windshields that were broken from this “sonic boom”.
This story caused us to ask the question: Can sonic booms break windshields? We did some research to find the answer.
First, we looked at exactly what qualifies as a sonic boom. A sonic boom is the audible component of a shock wave in the air. Sonic booms generate enormous amounts of sound energy, sounding much like an explosion; typically, the shock front may approach 100 megawatts per square meter, and may exceed 200 decibels.
A sonic boom is caused when an object, such as an airplane travels through the air. The airplane produces sound waves and as long as the plane is traveling slower than the speed of sound, then those sound waves can propagate ahead of the plane. However, if the plane is flying faster than the speed of sound, the sound waves that typically would propagate ahead of the plane are combined together creating a sonic boom when the plane flies past.
The effect is similar to that of a boat on still water. There is no disturbance of the water as the boat comes by, but soon, a large wave from the wake will roll onto the shore. In the same way, when a plane flies past at supersonic speed, the effect is not a large wake wave but rather a sonic boom.
It takes 160 decibels to break glass. Knowing this and that a sonic boom can exceed 200 decibels, it is easy to see how windshields could be shattered. Check out this video clip demonstrating how a wine glass can be broken using sound (http://www.youtube.com/watch?v=ECNDpCYvaOc&feature=youtu.be) and this video of a sonic boom actually blowing out windows (http://www.youtube.com/watch?v=swSt8WcVBG8&feature=youtu.be).
Paul Ryans, the Operations Manager at SunTec Auto Glass stated, “The science of what creates a sonic boom is quite interesting, but the reality of hearing it, especially for those people in Tennessee, must have been frightening. It makes one wonder what it was like for those that heard the first sonic boom when Chuck Yeager first broke the sound barrier in the California desert”.
If you live in the greater Phoenix, Arizona area and require a windshield replacement or auto glass repair, contact SunTec Auto Glass today. Our windshield replacement and auto glass repair technicians are NGA (National Glass Association) certified and service all vehicle makes and models. We use OEM (Original Equipment Manufacturer) auto glass and OEM parts, because you and your family's safety matters. We work with every auto insurance company and we accept most forms of payment. We offer free mobile service to Maricopa and Pinal Counties for your convenience. To schedule your windshield replacement, auto glass repair, auto glass tinting or auto glass etching, please contact us at (602) 753-6050 or by email at firstname.lastname@example.org.