For just two dollars ($1.99) you can download the “Blower” app from the app store. The aptly named Blower app turns your smartphone into something that blows really hard. Literally. But how, exactly, does the app allow a smartphone to blow out enough air to snuff out birthday candles? YouTube channel The Action Lab takes a scientific look at the phenomenon in a new video.
Boing Boing picked up on The Action Lab’s analysis of the Blower app, which comes, it seems, apropos of nothing. Although the host of the YouTube channel is definitely a fan of the science behind sucking, as demonstrated by this video looking at how the “world’s longest straw” works.
In the video above the channel’s host shows how the Blower app is indeed able to use a smartphone’s speakers to blow out candles. But while it seems like the physics behind the ability is obvious enough—we blow out candles all the time and it’s NBD—the nuances are fascinating. And counterintuitive.
The channel’s host notes that while a smartphone uses speaker cones to blow and suck on surrounding air—thusly creating vibrations in the surrounding air, and hence sound waves—the amount of air the speakers blow out and suck in is exactly equivalent. So how then, is the smartphone able to blow out candles?
As the channel’s host explains the Blower app functions thanks to the intrinsic way a speaker works. The host notes that even though speakers suck in and blow out the same amount of air, how they suck and blow differs. When a speaker cone sucks in air, it does so from all around itself; in an unfocused manner. Conversely, when it blows out air, it does so in a way that creates a “column” of sorts. This directed column has enough force that it can blow out, say, a birthday candle. Or very tiny bits of dust.
The frequency of the sound waves produced by a smartphone’s speakers matters as well. The Action Lab host notes that 240 hertz is the sweet spot for producing the best blow with a smartphone’s speakers. Although, frankly, that’s still nothing compared to what’s possible with an 18,000-year-old conch shell. But hey, who doesn’t love their phone blowing out their birthday candles?