At one time or another, most of us have seen a cartoon in which an opera singer uses her powerful voice to shatter glass. But can a human being really do that? The answer might surprise you because science says yes!

The laws of physics show that every piece of glass — actually, every material on Earth — has a natural resonant frequency. That frequency is the speed at which it will vibrate if struck.

For example, wine glasses are especially resonant because of their hollow, tubular shape. If you flick a wine glass with your finger, you will hear a ringing sound.

The resonant frequency of a glass could be any particular musical note. It just depends on the glass and how it was made.

If a singer sings the same musical note that matches the resonant frequency of the glass, the sound waves will vibrate the air particles around the glass at its resonant frequency. This will make the glass begin to vibrate, too. If a singer sings loudly enough, the vibrations can cause the glass to vibrate so hard that the glass shatters under the strain.

So can just about anyone break a glass with a song? Not quite. It’s much harder to do than it sounds.

Experts believe a singer has to be both very good and very lucky to break a glass with the voice alone. But it can be done…

For example, very fine, leaded crystal glasses are more fragile than others. Thus, it may be easier to break such a glass than a thick water glass.

Volume is another key factor. The louder the sound, the more air it displaces. Singing more loudly thus results in sound waves hitting a glass with greater force.

Breaking glass with an amplified voice has been demonstrated many times. A human voice without amplification, though, will usually fail unless the glass is quite fragile.

In 2005, the Discovery Channel television show MythBusters proved that a voice alone could break glass. Rock singer Jamie Vendera shattered a wine glass with a 105-decibel wail. By comparison, normal speech is usually around 50 decibels.

So do you have to have natural talent to break glass with just your voice? Not necessarily… but it couldn’t hurt! Finding the right note to shatter a glass will be easier if you’re a naturally talented singer.

Sometimes people are born with certain talents. At other times, people work very hard to develop skills they have into true talents.

For example, opera singers often must train for years. Many other famous performers and athletes, like Taylor Swift and Apolo Ohno, also have had years of training.

Even if singing isn’t your talent, you can still train and practice. If you set your mind to it, we believe you can achieve any goal you set for yourself.

 

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  1. Today’s Wonder of the day was very interesting. I have tried to break a glass but I have never succeeded. I saw those talent videos, and I couldn’t believe that little third grader playing the piano. I never learned to play piano, but I am playing the flute, right now. I am kind of good at that.

    I think that tomorrow’s wonder is going to be about contact lenses, or glasses. I can’t wait to find out! :)

    • We bet you are AWESOME at playing the flute, Meredith! Are you playing in your school band next year? We hope you have a GREAT school year! Thanks for visiting Camp What-a-Wonder today! :-)

  2. We think that it is fascinating that sound waves are powerful enough to break glass. It is interesting that you used the example of when you flick a wine glass you can hear a ringing sound.

    Does that that happen because of the hollow shape and the sound waves bouncing off the side of the glass? Also does in ringing work on every glass? At a place called Cosi a science museum, there is a glass bowl that because people are talking if you touch it it vibrates!

    A question we have is, does the voice have to be a high pitched sound or does it not matter? We love your site and we think it is awesome to think of those questions!

    • Thank you for such a GREAT comment, Sean and Connor! There are LOTS of factors that come into play when trying to break a glass with your voice! The pitch of your voice has to match the resonant frequency (the speed at which it will vibrate if struck) of the glass. The resonant frequency of the glass depends on the type of glass it is and how it was made. Then, you have to be able to hold just the right note for just the right length of time! It’s a lot of work and it takes a bit of luck, too! :-)

  3. Dear Wonderopolis,
    This wonder was extremely interesting. I had never known that you can break glass with only your voice. It was also interesting that you have to have a certain pitch to break glass, but what tone does it have to be? Is it a big deep tone or squeaky high pitched one?

    I’ve looked at some books that are about opera singers who broke glass with their voices, but I never knew ordinary people can break glass, too! Also, in the video, I was not expecting the glass to break. It sure surprised me!

    • Hi, Sarah! Thanks for sharing what you learned from this Wonder of the Day®! The tone and pitch of the singer’s voice are only two of the factors that contribute to how and when the glass breaks. The way the glass was made and the thickness of the glass also have a lot to do with it! So, a deep tone could break certain type of glass, while a squeaky high-pitched tone would break another type. It takes a perfect recipe of all of those things to make the glass break! :-)

    • Thank you for sharing your feelings about the Wonders of the Day®, Sofia! We appreciate your comment…you’re a GREAT Wonder Friend! :-)

    • Hello, Kaley! Thank you so much for visiting this Wonder of the Day® and for letting us know you learned something new about how a voice can break glass! :-)

    • We think this Wonder is amazing too, Ellen! We’re so glad you stopped by Wonderopolis today…thanks for leaving us this comment to let us know you did! :-)

    • We’re so glad you stopped by this Wonder of the Day®, “Me!” Make sure you have a grown-up around when you attempt this, so you don’t get hurt when the glass breaks! We care about all of our Wonder Friends! :-)

  4. I always thought that only very talented singers could break a wine glass. But in science we learned about an objects natural frequency. If it is a low frequency it has a longer wave and a bigger crest and it vibrates more slowly. If it has a higher frequency then it will have a shorter wave, a shorter crest, and vibrates more quickly. That video was was pretty amazing considering he had no practice o___o. Oh well reply soon XD.

    • We agree, Team McNeil 22, the video for this Wonder WAS quite amazing! We like the look on the boy’s face when the glass breaks…his expression was priceless! :-)

    • Thanks for visiting Wonderopolis today and leaving us a comment, Chloe! We appreciate your opinion about the human voice breaking glass!

    • Hi there, Julie! We think it’s GREAT that you are going to give it a try! Please be careful, though! Wear some safety goggles and be sure to let your parents know you’re going to try, too. We hope you’ll let us know what happens! :-)

  5. Wow!! My whole life I thought that breaking glass with your voice cannot really happen and that in cartoons the characters did it just to make viewers laugh! However, it sounds like it is very rare for people to do because conditions have to be perfect! My school has talent shows each year that are really fun to take part in or watch! When I do it, I like to dance because dancing is my talent! I have done a talent show with my friends before and we have gathered our parents and showed them pretending that they were our audience. Right now my friends and I are planning a talent show to preform to our parents and siblings. Sometimes putting on a little show can be super fun and gives you practice for the school’s next talent show so you can be a pro!!

    • Those soprano notes are more powerful than we thought, Gracie! We think it’s SUPER that you enjoy performing and make time for practicing in front of family and friends. It sounds like a blast!! We Wonder if you like to do a timestep or ball-change like the tappers in a past Wonder? Keep on dancing– with your feet and your heart!

      Wonder #234– Do You Need Special Shoes to Tap Dance? http://wonderopolis.org/wonder/do-you-need-special-shoes-to-tap-dance/ :)

    • We’re glad you think so, Christina! We hope you had fun WONDERing about high pitched voices that are powerful enough to shatter glass! Have a SUPER day! :)

    • We Wonder if you like to sing, Wonder Friend R? We hope you have a SUPER day– thanks for sharing your comment about our musical Wonder! :)

    • Isn’t that so cool, Wonder Friend Brooke? We are glad you enjoyed our Wonder video and learning all about the science behind sound! WOOHOO for WONDERing! :)

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Have you ever wondered…

  • How can a voice break glass?
  • Does all glass have the same resonant frequency?
  • What volume is usually required to break a glass with a voice alone?

Wonder Gallery

Try It Out

Ready to belt out a song or two? You may not be at Camp What-A-Wonder, but you can still grab some friends and put on your own talent show for family, friends and neighbors!

Can’t sing? That’s OK. Singing is just one of many talents you might see at a talent show. All sorts of people are good — talented — at all sorts of things. What talents do you have?

Can you sing? Play an instrument? Tell jokes? Juggle? Perform magic tricks? There’s really no end to the types of talents that might entertain an audience. Think about what you like to do and what you’re good at.

A good talent show will feature many different types of talents. Encourage your friends to share their talents with your audience.

If you can, videotape your talent show, upload the video to a site like YouTube or Vimeo, and email us the link so we can see your talent show!

For inspiration, check out a few video clips from talent shows:

 

Still Wondering

Check out Science NetLinks’ Sensational Sound resource to learn how sound travels through air, liquids and solids.

 

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