Archives for: "February 2020"

Hoar Frost on Plastic

February 17th, 2020
The pattern of hoar frost depends on not just the current and prior conditions, but also on the surface. If the surface is less attractive to water, that is, more hydrophobic, then the hoar crystals tend to be more further spaced apart. Or even more… more »

Raindrop Hillocks and Ground Ice

February 16th, 2020
Ever see these small centimeter-scale hillocks in dirt or sand, usually topped by a small pebble or twig? To me, they look like a miniature mountain landscape. A brief reflection on their appearance suggests erosion by raindrops: The drops fall down on… more »

The Curious World of Ice and Snow: Part 3 of 3

February 8th, 2020
These 14 slides are the final (third) section of my Science Cafe talk. (Plus two slides added as an introduction.) As in the previous section (previous post), this section mostly has ice forms that come from the melt, but the ice shapes here are a… more »

The Curious World of Ice and Snow: Part 2 of 3

February 8th, 2020
As I mention in Part 1, these are slides I gave for a Science Cafe discussion session in 2012. This section focuses on ice that forms directly from the melt, that is, the liquid phase. Contrast these cases with those in part 1 in which the ice grew from… more »

The Curious World of Ice and Snow: Part 1 of 3

February 4th, 2020
In 2012, I gave a "science cafe" talk with a local series sponsored by the Pacific Science Center, KCTS public television, and Science on Tap. The title was "The curious world of ice and snow". The location was a bar in Kirkland, but open to all ages.… more »