Photo by Chris Slupski on Unsplash

Nana: Are you listening to the Beach Boys? They are ancient!

Nina: Not as ancient as Mozart and Beethoven Nana.

Nana: True, but those are classics. This one is Good Vibrations right? Your mom drove me crazy with this one when she was in her teens. She loved it and would play it over and over again. I hated it then, but now it makes me nostalgic.

Nina: Mama loved this song? What else did she like Nana? Her birthday is coming up soon, and I’d like to compile a play list for her.

Nana: Well she loved American Pie, some of the Abba songs. Mama Mia was her favorite from that album, and she loved Hotel California. That’s what I can recall now but I can give it some thought and get back to you. Anyway how did you come across Good Vibrations? It’s so old.

Nina: Not older than you Nana. <wink> Did you jam to it in your youth? Were you ever young Nana?

Nana: None of your cheek young lady.

Nina: Sorry Nana. I couldn’t resist. Anyway since you asked I was googling vibrations and music and came across the song. Isn’t it amazing how music is just basically vibrating air molecules tap dancing on our eardrums.

Nana: Haha! You paint a funny picture, but yes all music is generated from vibrations weather it comes from beating a drum, or plucking a guitar string or even blowing in to a flute.

Nina: Yesterday I was watching Harry Potter and the Prisoner of Azkaban and they showed The Fat Lady trying to shatter a wine glass by singing.

Nana: Well it ain’t over till the fat lady sings, you know.

Nina: <rolling her eyes> Yeah Nana. See sometimes you can’t resist either.

Nana: Touche.

Nina: Anyway, so I wondered if it’s really possible for human singing to shatter a wine glass. I looked it up. It turns out that the note would have to hit the precise resonant frequency of the glass which would depend on it’s size and shape. At this frequency, the air inside the glass would vibrate violently causing it to shatter, but there is a catch.

Nana: Isn’t there always?

Nina: Well, the voice has to be really loud and still consistently maintain the resonant note. That’s tough. It’s been done many times using an amplifier but it’s extremely difficult and therefore rare with the unaided human voice.

Nana: So why didn’t the fat lady just use sonorus?

Nina: Hmmm. Nana you make a good point, and I see that you are a closeted Harry Potter fan. Anyway I am going to try with my voice.

Nana: I don’t know about the right note but you are quite loud.

Nina: So you have often pointed out Nana, but I’ll try many different glasses. I may get lucky.

Nana: What do you mean?

Nina: Apart from the resonant frequency and volume, there is one more factor that makes a huge difference.

Nana: What’s that?

Nina: Wine glasses all have some microscopic defects that are invisible to the naked eye. These defects are of various types and usually weaken the structure, but not noticeably. But some of these defects if they are in just the right place, can have particularly destructive effects when the air in the glass vibrates at the resonant frequency. So hopefully one of the glasses will have the proper defect.

Nana: Oh I think I am going to move to a hotel till Music month is over. I simply can’t tolerate these torturous experiments any more. Even my noise canceling headphones are out of battery. But before I go I’ll leave you with a terrifying vibrational fact of my own. Hopefully it will give you nightmares.

Nina: What’s it about Nana?

Nana: It’s about world war one.

Nina: I hate wars Nana.

Nana: And I hate your music experiments. So I read in a Biggles book, that during world war one they used to drop empty milk bottles from planes, because the sound made by the air whistling through the bottle was so loud and scary, it terrified people and caused panic. Anyway if you must experiment with music couldn’t you do it quietly?

Nina: How could I possibly do that?

Nana: I was reading an article about the effects of ultrasonic frequencies on brain activity. It’s an interesting field of research, but the experiments are not noisy, since we can’t actually hear ultrasonic frequencies. It still affects the brain though.

Nina: So you mean I should get a dog whistle and see if it makes you do tricks?

Nana: Hmmph! Why do I even bother?

This post is a part of the #NinaAndNana series I co-host with Lavanya Srinivasan. Her posts can be found here.