Chuck Norris can charge phones with his voice, you can't

2021-05-07

Yesterday we stumbled upon the news that Sang-Woo Kim of Sungkyunkwan University found a way to convert noise to electricity, which can in turn be used to charge your cell phone. As usually when we come upon such stories, we pass it around the office, we have a good laugh and get done with it.

However we were amazed to see that this went all over the news as if it really was some kind of a breakthrough so we decided to make a few things clear here. We see you rising your eyebrows here and wonder – how come we are not excited by the prospect of charging our phones by simply talking to them? Well, that’s just because it’s impossible and it’s never going to happen as anyone with a basic understanding of physics will tell you.

For starters the device that converts sound waves to electricity has been around for ages (and your phone has at least one) - it's called "microphone". The problem is that it generates so little electricity that it's not useful for anything but transmitting small amounts of data.

Then comes the source claiming that at the current state of their project they are producing 50 millivolts from 100 decibels of noise, but they promise to do better in the future. Do you know how much 100 decibels amount to? Let's just say that a gasoline engine chainsaw produces noise in the range of 90-112 decibels. Yes, 100dB is that loud.

Now we don't deny their findings, but no matter how much improvement they achieve, they won’t be able to bend the laws of physics. There’s just no way to produce more energy from the sound waves than has been used to create them and that's quite a small amount in the first place as the scientist above testify themselves. Not to mention sound loses its energy rapidly while traveling through the air.

Sorry for bursting your bubble, but you should forget about it - it's not happening. The energy of the sound will never be enough to charge your phone, unless you live right next to the Niagara falls.