How old are your ears? A video from ASAP Science has gone viral with a test of hearing that's hard to resist.

The video cranks up the frequency of a sustained pitch, beginning at 8,000 hertz and matching the frequency with an average age. At the end of the test, you may be patting yourself on the back, thankful for all those rock concerts your parents didn't let you attend.

Or you could be like some of the commenters at the ASAP Science YouTube channel, wondering why they're 17 but their hearing is 30.

Either way, ASAP makes the test entertaining with its trademark bright diagrams and concise explanations. Now we know why we lose the ability to hear higher pitches over time. Tiny hair cells in the inner ear responsible for picking up different frequencies break down over time with the constant barrage of noise and loud sounds.

Biologists Mitchell Moffit and Gregory Brown are the founders and creators of ASAP. In December, when their YouTube channel surpassed 10 million views, Moffit told Scientific American the inspiration behind their channel: "We want to explain the science behind the coolest things we learned in school."

The duo, he said, wanted to talk about the scientific concepts that really resonate with people. For ASAP, "people" sometimes veers to the younger crowd (those, perhaps, whose ears are 20 or younger). Among video titles: "Will Dancing Get You Laid?" and "The Science of 'Morning Wood.' "  There are subjects, however, for a wider audience: "The Scientific Power of Thought," "Can Money Buy Happiness?" and more. 

For science fans, it's worth checking out.

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