Like many of us, Emily Worden has endured her share of Zoom meetings over the past year and a half. And somewhere along the way, she found herself asking a question that she figured was tailor made for the Curiosity Desk. She brought it to our attention on Twitter and we decided to take up the case.
First, we gathered as many microwaves as we could get our hands on and ran a quick, ad-hoc experiment to test how similar those different microwaves actually sounded. Our conclusion? Pretty darn similar. We then turned to Richard Hughes, a principal designer with Whirlpool Corporation, for some insight.
He explained that, for decades, the same technology has been used in nearly all microwaves to generate that classic sound: A little device called a Piezoelectric buzzer
“It's essentially a membrane that vibrates,” said Hughes. “[It’s] electrically charged and vibrates to create a sound fairly very similar to the way a speaker works.”
Piezoelectricity was first demonstrated by Pierre and Jaques Curie way back in 1880. It is — in essence — an electric charge that accumulates in certain materials when physical pressure is applied. That piezo part comes from a Greek word that means “squeeze or press.”
The piezoelectric buzzer harnesses this charge to generate that simple beep.
It was first brought to market by Japanese manufacturers in the 1950s and quickly proved to be a worldwide hit. On the one hand they are remarkably versatile — used not just in microwaves, but also smoke alarms, timers, and all sorts of other gadgets. On the other hand, they are quite limited in what they can do.
“We could set the frequency, but we couldn't do much more than that,” said Hughes. “The frequency and the length of that note was about all we had available to us.”
And this is why, for decades, nearly all microwaves sounded so similar. But today, it’s a whole different ball game. Thanks to digital technologies, developed mainly for mobile phones, a veritable symphony of sounds is available at the touch of a button. So, the days of the Piezoelectric buzzer – and that iconic microwave beep – could be numbered.
WATCH: Why do all microwaves have the same 'beep'?
If there is something you've been itching to know more about, email The Curiosity Desk or send in your question below. Edgar might just dig up the answer in a future episode. For more from The Curiosity Desk, follow Edgar B. Herwick III on Twitter and subscribe to the GBH News YouTube Channel.
