Vampire hunters have crosses, garlic, and wooden stakes to take care of the undead, but anyone aiming to take down a werewolf won’t have many silver bullets to fight their mangy beasts… except actual silver bullets. But knowing lycanthropy enthusiasts’ susceptibility to moonlight, is there a way to use science and get the upper hand (or paw)? Totally.

In my latest Because Science, I’m figuring out how to turn a werewolf back into a human with science. On a previous episode, I ranted about werewolves not recognizing that the Moon is technically always all there—the only thing that changes is the amount of light coming from its surface—so werewolves should therefore be turning all the time. Enough of you took issue with that point, so in this episode, I’m trying to determine exactly how much light it takes to transform a werewolf just enough to be picked out of a crowd.

All moonlight is actually reflected sunlight. So, if we know the intensity and brightness of that sunlight bouncing off the Moon, we should be able to replicate it in broad daylight (the safest time to check for werewolves). According to my math, you make a werewolf detector out of a large mirror in the right conditions. To find out what those conditions are, check out my latest episode above!

Check out my last video on the physics of The Flash’s famous “Infinite Mass Punch,” subscribe to this playlist to stay current with the show, buy a Because Science shirt (you know why), and follow me on Twitter to give me a suggestion for the next episode!