How good is your hearing? Mitchell Moffit and Gregory Brown, the Canadians behind AsapSCIENCE, have devised a simple test to help you check "how old" your ears are.
It turns out that as we age, the "hair cells" in our ears tend to break down because of exposure to loud noises. The first cells to go are those that let us hear high-frequency sounds.
This video offers a test for your ears. By listening to sounds at different frequencies, you can find out roughly what age your ears are: most people over the age of 24 won't be able to hear a lot of the sounds.
It's a fascinating - and as MSN points out, maybe a little depressing - look at what's happening to your hearing as the years go by.
A note: you'll want to set this video to 1080p and throw on some headphones to make sure the sound is accurate.