What Are Those Spikes on Your Ice Cubes?
I drink a lot of Coke. And along with the Coke, I drink a lot of ice. Some days, it seems like the Coke is just a delivery mechanism for the ice (as my sister once said about hotdogs and condiments).
I notice, from time to time, little spikes or finger of ice growing on top of my ice cube tray. What the heck are these upside-down icicles, these tiny ice phalli, and how did they get there? Well, the The Experimental Nonlinear Physics Group at the University of Toronto knows:
The short explanation is this: as the ice freezes fast under supercooled conditions, the surface can get covered except for a small hole. Water expands when it freezes. As freezing continues, the expanding ice under the surface forces the remaining water up through the hole and it freezes around the edge forming a hollow spike. Eventually, the whole thing freezes and the spike is left.
Hallelujah! Another of life’s tiny mysteries solved. That ice cube spikes page is pretty cool–they’ve even got a couple of videos showing the cubes forming.
