Science Buddies: "Ask an Expert"

Hi,

My son is having problems with his science project. His question was "Will sound break other material besides glass?" His hypothesis is that it will and according to his research it should. He is using a tuner that he downloaded to his computer and an amplifier that we already had. He thought he would begin with breaking a wine glass as a starting point and work his way to other material from there. He has tried 2 different types of stemware type glass. He has used a straw and a piece of paper folded over the edge of the glass to see if he can tell what the frequency is, but nothing happens.

We believe the amplifier is a 50 watt amplifier. It is a free app called "Tone Generator" that he downloaded from the Microsoft store. Does the type of stemware glass matter? If everything has a frequency, we are thinking it shouldn't really matter. What are we missing? Is the tuner not strong enough or is it the amplifier?

We appreciate your help.
Brenda

Hi Brenda - this article might help a bit:

https://www.scientificamerican.com/arti ... ter-glass/

I noticed two things:

The sound used to break the glass needs to be LOUD. Over 100 decibels. You can download a separate "decibel meter" app for your phone to measure how loud a sound is (Google Science Journal is a good one, we have some projects that explain how to use it if you search for it on our site). Your son should definitely wear ear protection when working with sounds that loud (think of it like a lawnmower or a chainsaw - exposure to sounds that loud for a long period of time can cause hearing damage). Putting the glass right in front of the speaker might help, since sounds get quieter as you get farther away from the source.

Expensive crystal wine glasses are actually easier to break than cheap ones. That's sort of a bummer for a science project because if you are TRYING to break the glasses, you probably want to use cheap ones, or it's going to be a pretty costly project.

It looks like there are a bunch of articles and demonstrations about this phenomenon online, including a Mythbusters episode you may be able to find. If your son does more research on other demonstrations, he might be able to get more details (decibel level, frequency, type of glass they used, etc) and reproduce a successful experiment.

Hope that helps,

Ben