It happens to the best of us: You park a few rows from the supermarket entrance and make a mental note of your spot, but when you return an hour later, groceries in hand, your car is nowhere in sight. The solution is both odd and simple: Hold your car keys to your head and press the lock button. Believe it or not, you’ll hear your car beep, even if it’s far away.
Not convinced? After watching a viral TikTok from the Boston Museum of Science about this strange trick, I tried it on my own car — and it worked. Alex Dainis, PhD, explains the phenomenon below.
Why Your Head Can Help You Find Your Keys
“Car remotes work by sending out a short range radio signal,” Dr. Dainis explains in the video. “That signal usually travels about five to 20 meters [a little over 65 feet] before it peters out and you can’t reach your car anymore. But you can use your head to amplify it, increasing the distance it can travel.
“Just like the rest of your body, your head contains a lot of water,” she continues. “When you hold the key fob against your head, the electromagnetic waves from your car remote interact with the water molecules in your head. This moves them around. The movement creates a wave that adds together with the remote wave, amplifying it and increasing its range.”
In her video, Dr. Dainis tests out the hack herself. She walks forward until her car keys stop working — about a 25-meter distance. She presses her car lock button to show that the remote doesn’t work. Then, she raises the remote to her head, touches it to her neck, and presses the lock button. Voilà: The car beeps.
Potential Downsides of the Car Key Trick
Some users commented below the video that they were worried about safety. This fear is understandable — is it really okay to use your head as a radio? However, since it’s such a quick use (and exposure is low-level), most sources agree that it isn’t cause for concern. To put things in perspective, using a hairdryer is likely more dangerous, since hair dryers emit EMF radiation. (EMF, or electromagnetic field radiation, may pose a danger to our health by increasing cancer risk.)
So, the only real downside: While this trick certainly helped extend my car remote’s radio range, it only went so far. I estimated that it petered out at about 85 feet away. Still, that extra 20 feet of range could really help the next time I lose my car in a parking lot — and it’s all thanks to science.