Frozen bubbles
Last month, photographer Angela Kelly took a solution of soapy water out into the cold in Washington state, to make an amazing series of frozen-bubble photos. They have been widely shared these last few days. The science is pretty simple: the water freezes in the bitter air but the soapy solution allows it to retain it bubble form. As soon as you touch them, though, the heat from your fingers will melt the bubble. The largest of them make for photos like Kelly's, while the smallest ones can roll around on the ground like tiny marbles.
A few years ago, science teacher Nathan Ziegler explained the phenomenon on video as part of a great series called Minnesota Cold:
POLAR VORTEX: These Cold-Weather Experiments Will Help You Pass The Time Till Spring - Business Insider
