Have you ever seen a plane fly overhead at a supersonic speed? If so, you may have heard a loud “boom” as it passed by. Did it explode? Nope! You can still see it flying. Then what was that sound? It was a sonic boom.

A sonic boom is a loud sound kind of like an explosion. It’s caused by shock waves created by any object that travels through the air faster than the speed of sound. Sonic booms create huge amounts of sound energy.

When an object moves through the air, it makes pressure waves in front of and behind it. Have you ever seen a boat move through water? The bow waves (front) and stern waves (back) are similar to the invisible pressure waves created by an object as it moves through the air.

These pressure waves travel at the speed of sound. How fast is that? Pretty fast! Sound travels at different speeds through different types of materials. It also varies by altitude and temperature.

At sea level and 68° F, the speed of sound through air is about 761 miles per hour. At an altitude of about 20,000 feet where the atmosphere is thinner and colder, sound travels at about 660 miles per hour.

Austrian physicist Ernst Mach developed a method of measuring airspeed relative to the speed of sound. If a plane if flying at the speed of sound, it is said to be going Mach 1. A speed of Mach 2 would be twice the speed of sound.

As an object, such as an airplane, travels faster and faster, the pressure waves can’t get out of the way of each other. They build up and are compressed together. Eventually, they will form a single shock wave at the speed of sound.

The sonic boom we hear caused by an airplane flying at Mach 1 usually takes the form of a “double boom.” The first boom is caused by the change in air pressure as the nose of the plane reaches Mach 1, and the second boom is caused by the change in pressure that occurs when the tail of the plane passes and air pressure returns to normal.

As long as an airplane travels at Mach 1 or faster, it will generate a continuous sonic boom. All those in a narrow path below the airplane’s flight path will be able to hear the sonic boom as it passes overhead. This path is known as the “boom carpet.”

If you’re wondering about how pilots handle sonic booms, they actually don’t hear them. They can see the pressure waves around the plane, but people on board the airplane can’t hear the sonic boom. Like the wake of a ship, the boom carpet unrolls behind the airplane.


72 Join the Discussion

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    • We think it’s GREAT that you are using the clue to try and guess each next day’s Wonder, TJ! We can’t wait to visit Wonderopolis tomorrow morning to see if your new guess is right (we hope it is…we LOVE learning about airplanes)! :-)

  1. They can see the pressure waves? That’s pretty cool. I wonder if anyone has video of that because it’s pretty cool and unfortunately I can’t watch any of your videos.

    • Hi, Saffron! We’re super sorry you can’t see any of the videos in Wonderopolis! Are you visiting Wonderopolis at school? If so, it might help you to know that some schools and school districts place an internet “block” on videos from certain websites because they are trying to protect their students. You might want to check with your teacher to ask if he or she might be able to get the block removed so you and your classmates can see all the videos on Wonderopolis. :-)

  2. I think this writing is so cool. I’ve been in a boat when it is going fast on the water and it does make some loud noises. This is so awesome!!! Sonic boom’s sound so cool and sort of weird. Thank you for responding after all of my comments!!!!!!!!!

    • We’re SO HAPPY that you thought today’s Wonder about sonic booms was cool, Cassidy! We really appreciate hearing what you think about the Wonders you explore when you visit Wonderopolis! :-)

  3. I think this wonder of the day is wonderful and so full of interesting facts to learn about sonic booms!! I think this wonder of the Day has a lot of interesting facts such as what you wonderful people that put out these great wonders said about how the speed of a sonic boom through the air is about 761 miles per hour!!!!!

    • We thought learning about sonic booms was SUPER fun today, Hannah, and we’re glad you did, too! Now we both know what makes that “boom” sound…COOL STUFF! :-)

    • Thanks for sharing your thoughts about sonic booms, Shundee! We’re so happy to count you as a Wonder Friend…YOU ROCK! :-)

    • Hello, Sydney! Thanks so much for stopping by Wonderopolis today! A sonic boom isn’t the same as a bomb (although sometimes the loud sound you hear when a sonic boom happens sounds that way). It has to do with sound waves and sound energy. We encourage you to re-explore today’s Wonder to learn more about sonic booms! :-)

    • That’s a SUPER guess about tomorrow’s Wonder, Stefani and Kd! Way to go! We will all have to check out Wonderopolis tomorrow to see if your guess was correct! :-)

    • Hi again, Stefani and Kd! Thanks for leaving us another awesome comment! It’s OK to change your mind in Wonderopolis…it means you’re doing more WONDERing! :-)

    • That’s a WONDERful guess, Miss Kirsten’s GT class! We can’t wait to visit tomorrow’s Wonder to see if you guys are correct…GREAT JOB on using the clue to WONDER about what tomorrow’s Wonder might be! :-)

    • That’s OK, Vikkie! Sometimes it’s just as much fun to visit Wonderopolis and let the Wonder of the Day® be a surprise! We like to do that, too! :-)

  4. Wow, that was so cool. I learned some interesting facts about sonic booms. That video rocked the house. I think tomorrow’s wonder is going to be about stars and the planets.

    • We think this comment of yours ROCKS, too, Joseph! Thanks for letting us know you learned some cool new facts about sonic booms by exploring today’s Wonder! :-)

  5. Wow!!!! I never knew this. Oh, and, there has been something that I’ve been Wondering about. Have you heard of the chupacabra? If you have, what is it? Is it real? Just wondering. ;)

    • Thanks for stopping by today’s Wonder for some fun learning about sonic booms today, Grace! We think a future Wonder about chupacabras is a GREAT idea! Thanks so much for suggesting it! :-)

  6. I thought today’s wonder was interesting, but I didn’t like the video. I think tomorrow’s wonder is going to be about an air show.

    • Thanks for sharing what you thought about today’s Wonder and the video for it, Juliana! We really appreciate your opinion! :-)

    • That’s right, youngfreedom! Thanks for sharing what you know about sonic booms with everyone in Wonderopolis today! :-)

    • Hello, Mrs. Wilbanks! Thanks so much for your nice comment! We’re super glad you stopped by Wonderopolis today! :-)

  7. Sonic boom is an impulsive noise similar to thunder. It is caused by an object moving faster than sound, about 750 miles per hour at sea level. An aircraft traveling through the atmosphere continuously produces air-pressure waves similar to the water waves caused by a ship’s bow. When the aircraft exceeds the speed of sound, these pressure waves combine and form shock waves which travel forward from the generation or “release” point.

    • WOW! You sure do know a lot about sonic booms, youngfreedom! Thanks for sharing some more great facts with us! :-)

    • The sonic boom in the video for today’s Wonder WAS super loud, KF Dragons! Have you guys ever heard a sonic boom in real life? We have only heard one before here in Wonderopolis, but it was SUPER LOUD, too! :-)

  8. Wow!!!! That is a quite interesting wonder for today! Do you think you could do a wonder about monkeys? They are my favorite animal! I really love wonderopolis! It is awesome!!!!! :D

    • Hi, Tessa! We like monkeys, too! We think there is a Wonder of the Day® coming up soon that you will REALLY enjoy exploring (hint, hint)! Keep your eyes open and keep checking Wonderopolis! :-)

  9. We really liked today’s wonder! We learned all about sonic booms. We think tomorrow’s wonder might be about birds or jets.

    • Those are two SUPER guesses about tomorrow’s Wonder, Mrs. Bertz’s class! You guys ROCK! Thanks for hanging out in Wonderopolis and learning about sonic booms with us today! :-)

  10. Thanks WONDEROPOLIS for the great wonder of the day it was really neat and familiar because my Dad works at the Toledo airport and hears fighter jets all the time! Oh I tried the wonder of the day #175 about broadway and the video didn’t show up but I did read about it it was really neat! I loved it! Thanks :)

    • Thanks for sharing your personal connection to this Wonder, Madalynn! We think it’s so cool that your dad gets to hear jets all the time where he works…NEAT! Thanks for letting us know about the video for Wonder #175…you’re a GREAT Wonder Friend! We’ll get that fixed super soon! :-)

  11. Remember on wonder of the day number 509 Have you ever lost your marbles? I commented on it and said that it was the very last comment I would put on Wonderopolis. I meant to say that I wouldn’t be commenting on Wonderopolis for a long time.


    • We appreciate any comment you leave for us, TJ! It means you are visiting Wonders and learning new things in Wonderopolis…and we think that’s GREAT! :-)

  12. I thought the wonder of the day was AWSOME!!! I never really knew what sonic boom meant until now. I think you guys should do a wonder on titanoboa snakes!!! I know every single person who goes on wonderopolis will read this!


    • Thanks so much for your suggestion for a future Wonder of the Day®, Emma! We didn’t know about titanoboa snakes before, so we just did a little WONDERing about them…they were HUGE! Thanks for teaching US something really cool today! We love learning! :-)

  13. I think tomorrows wonder will be about airplanes. I am in the hospital again for an anyphylaxis reaction and I am very bored sitting around. Got to go! I am getting wheeled to the operating room. :( So nervous! (P.S. My real name is Emma!)

    • We hope you are feeling better, Food Allergy Girl! We know those reactions can be quite scary! We are thinking about you today…thanks for being a GREAT Wonder Friend! :-)

  14. I would have to disagree on some of these theories, a sonic boom happens whenever something is going so fast that it breaks the sound barrier causing the sound to be delayed, when that happens you get all of the sound at once causing a loud boom.

  15. Hi, this is Srikar from Mrs.Caplins class.It was really cool when that guy made a sonic boom with soapy water.I learned that sonic boom is a loud sound caused by shock waves created by any object that travels through the air faster than the speed of sound.I also learned that at sea level and 68° F, the speed of sound through air is about 761 miles per hour. At an altitude of about 20,000 feet where the atmosphere is thinner and colder, sound travels at about 660 miles per hour.I had to use context clues when I read the word altitude and I learned that altitude means how high something is.When was the first sonic boom made?

    • Hello Srikar! You have done a lot of WONDERing and taught us NEW things about sonic booms. The first item that created a sonic boom is a whip. The end of the whip, known as the “cracker”, moves faster than the speed of sound, thus creating a sonic boom :) How neat is that?!

  16. This wonder was my favorite yet. I did not know that however high you are that the speed varies to generate a sonic boom. Like at sea level you have to be going 761 miles per hour to generate a sonic boom. But at 20,000 ft you can generate a sonic boom at the speed of 660 miles per hour. I did not know that the pilot of the airplane can not hear the sonic boom. I thought that the sound would be much louder. Do you know how loud the loudest sonic boom was and was it made by an airplane?

    • WOW! You learned a LOT about sonic booms by visiting this Wonder, Matthew…we think that ROCKS! We’re not sure about the loudest sonic boom…we will both have to do some more WONDERing about that one! :-)

  17. Two new vocabulary word I learned in this article were bullwhip and sonic boom. A bull whip is something that can break the sound barrier.It is exactly like on of those jets that can break the barrier of sound.A sonic boom is when something breaks the barrier of sound. It makes an enormous sound,that happens when something breaks the sound barrier. Such as a bullwhip. Two new facts I learned is that I never actually new that something could break the barrier of the sound. I thought that it was impossible to stay alive after breaking the barrier of sound because I heard that a jet was on the mission to break the barrier of sound and the jet exploded. I wonder if there was ever any kind of alarm clock or something other than that, which produces sound, that can break the barrier. Because I want to get one of those. I also want to get a bullwhip. I’m very exited to write more. BYE (:

    • We like how your Wonder brain thinks, Team McNeil 14! It is interesting to think about an alarm clock that could break the sound barrier. We bet if we had an alarm clock like that, we would wake RIGHT up and NOT hit the snooze button! :-)

    • We liked that part of the video, too, Madison! We did some WONDERing about when the video was taken, and we discovered that it was about 4 years ago! Pretty cool, huh? :-)

    • That’s a really great question, Buckley! We think that the plane would have to be able to travel at the speed of sound. Smaller planes, like single engine planes, probably can’t travel that fast. It’s fun to WONDER about that, though! :-)

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Have you ever wondered…

  • What is a sonic boom?
  • How fast does sound travel?
  • Can you create your own sonic boom?

Wonder Gallery

blue angel_shutterstock_6232333Vimeo Video

Try It Out

Do you need an airplane to make a sonic boom? Not necessarily! Head online to watch a video of Chris Giorni from Tree Frog Treks making a “sonic boom” using a few common household items.

You might also be able to make your own sonic boom in your yard if you’ve been to the rodeo recently. Do you have a bullwhip? Bullwhips are common on farms, and they also make great souvenirs at the rodeo.

If you’ve ever used a bullwhip, you’re probably familiar with the loud cracking sound it makes. That sound is actually a tiny sonic boom. When a whip is swung, energy travels from your hand through the whip to its end.

By the time all that energy travels to the end of the whip, its tip — called the “cracker” — is traveling faster than the speed of sound. Like a supersonic airplane, the end of the whip surpasses the speed of sound and the bunched-up sound waves make the cracking sound you hear!

Scientists believe the bullwhip may have been the first human invention ever to break the sound barrier. So, if you have a bullwhip at home, give it a crack. You probably never knew you could create a sonic boom in your own yard!


Still Wondering

Check out Science NetLinks’ Sprinter Advantage resource to learn more about how the speed of sound may give Olympic runners closest to the starting gun a slight advantage.


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