Luminol makes pennies glow (but not for the reason you think)

Spritz luminol on your pennies and they’ll glow. Don’t worry! It's not blood — your penny's just been framed.

We’ve shown you how to make your pennies glow with some heat and some acetone, but pennies can also glow when exposed to a certain preparation of luminol. You may now be experiencing the urge to throw away your pennies. Relax. Luminol got famous on TV for uncovering both crimes and poorly sanitized hotel rooms, but it can be made to glow for more innocent reactions.

To set up the experiment, grab about 10 milligrams of powdered luminol and add 10 milliliters of a 10% ammonia solution. Add about one milliliter of 3% hydrogen peroxide. Mix it up and put it in 100 milliliters of distilled water. Now you’re ready to go!

Pour a little of the mixture out into a dish and add a penny. Not only will the penny glow, but it will leave trails of ghostly light as you tip the dish to move it around. It might look like your supposedly innocent penny has lived a life of vice and sin, but it’s actually just trying to be helpful.

Crime scene investigators mix their luminol powder with hydrogen peroxide and something called hydroxide salts; these salts form a negatively charged team of oxygen and hydrogen. These hydroxides react with the luminol to form a large, negatively charged molecule, but if the solution doesn’t hit anything suspicious, nothing happens. If the solution hits something with iron — such as the hemoglobin in blood — or hits certain enzymes, the hydrogen peroxide in the solution comes into play. Two oxygen atoms get wrenched off , and skip over to the luminol hydroxide combination. They create a very unstable molecule, and its creation requires two electrons from the luminol to sink to their ground state, and give off light. The unstable molecule also breaks down and gives off more light. The result is a glow.

But blood isn’t the only thing that can make the solution glow. As shown in the past glowing penny post, the copper in pennies is able to grab oxygen atoms and transfer them to whatever molecule needs them. The iron in blood catalyzes the reaction by wrenching oxygen off the hydrogen peroxide, and the copper in pennies does the same. As soon as the coin hits the solution, the copper will react and the solution will glow.

But if you want to bleed on your pennies, that would probably work too.

Top Image: Jack Spades

Via Nurd Rage and OMSI.