Can chocolate shimmer? Yep!

You know how your parents are always telling you not to play with your food?

Well, for the most part, they're right. (Seriously, your taco is not better as a pirate ship and we don't need it sailing through Lake Refrito...) But every rule is made to be broken sometimes. Just ask California maker Samy Kamkar, or as we like to call him...

THE MAN WHO MADE CHOCOLATE SHIMMER.

I’m finally getting some decent results producing 100%-edible iridescent tempered chocolate. The colors are from the chocolate (not any ingredient or coating) diffracting light after being forcefully molded onto a diffraction grating in vacuum. pic.twitter.com/6wpbsIKh5C

— Samy Kamkar (@samykamkar) May 9, 2020

Amazing, right? How did he do it?

Just physics

You might instantly think that he added something to the candy. We certainly did. Some chemical, maybe an oil since it kind of looks similar to how oil does when pooled on top of water.

But it's really just plain old chocolate. Instead of an additive, the effect comes from physics. Specifically, a principle called diffraction.

Diffraction happens when white light (which is made up of all the colours we see) is split and broken apart into separate colours when it hits a surface. This happens when the surface that white light hits consists of tiny, parallel grooves. Samy made his chocolate shimmer by using diffraction.

After failures attempting lasing gratings, finally designed mold in @adskFusion360, laser cut acrylic plates (variable thickness) w/@glowforge, turned rods w/Grizzly G0765, CNCd diffraction grating w/@Inventables Carvey, tempered+pressure injected chocolate, pulled vacuum @ 4torr pic.twitter.com/pKsS1tuV7e

— Samy Kamkar (@samykamkar) May 11, 2020

Using a 3D-printer, he made a mold that has hundreds of micrometer-sized grooves. Then he poured the chocolate in, and allowed it to cool. The finished candy had the inverse (or opposite) of the parallel groove pattern on its surface, allowing it to diffract light ...

And shimmer!