Unless otherwise noted, all visuals are used with permission of Royal Society Publishing, from Watson et al 2015, “Removal mechanisms of dew via self-propulsion off the gecko skin”, J R Soc Interface (2015) 12 (105): 20141396; permission conveyed through Copyright Clearance Center, Inc.

Further reading:
www.smithsonianmag.com/science-natu...
www.brighton-science.com/blog/what-is...

References:
royalsocietypublishing.org/rsif/article...
journals.aps.org/prl/abstract...
pubs.aip.org/aip/apl/arti...
pubs.acs.org/doi/10.1021/...
www.pnas.org/doi/full/10....

And so that energy makes the combined droplet spring off the gecko’s skin! This has the added benefit of taking dirt and microbes along with the water, keeping the gecko clean, and some insects even use this strategy to stay clean too. If only I could put micro-hairs on my kitchen windows…

8/8

If these two droplets combine (often because the droplets grow because of humidity in the air), the whole system suddenly has way more energy than it ought to—the two-droplet configuration had more energy than the mega-droplet configuration should, and that extra energy has to go somewhere…

7/8

But what if there are two water droplets? The energy of this system is defined by the area of the interface between the water and the gecko skin—the more area, the higher the energy. Two separate droplets have more energy than one big droplet:

6/8

That’s a bit of an overstatement—the geckos don’t exactly “make” the water do anything, since this is a passive process. When water forms a perfect sphere on the gecko’s skin, it’s stable: there’s no excess energy or force in the system that makes the water droplet want to move around.

5/8

Okay, but surely if enough water gathered on the gecko it would start to get wet, right?

Geckos prevent this eventuality by making water literally jump right off of them.

4/8

Geckos achieve these large contact angles, or beading, with specialized hairs on their skin. Air gets trapped between these tiny hairs, which makes it difficult for water to spread out and penetrate down to the lower surface of the gecko’s skin.

3/8

First—what does it mean to be wet?

Turns out physicists defined this long before the is-water-wet-wars started: a wet surface has a small “contact angle” with water, meaning the water doesn’t bead up.

Take a look at the water on a gecko’s skin—looks more like the “non-wetting” case, right?

2/8

buddy I am a physicist I am not supposed to know what PCR is

References
www.nature.com/articles/178...
www.nature.com/articles/s41...

Special thanks to @zztony.bsky.social for bringing these guys and their weird drifting dynamics to my attention!

The individuals with different sail-handedness move in opposite directions! This is thought to help prevent mass beaching events; since the Man o’ War doesn’t swim under its own power, if they all drifted in the same direction and unluckily hit land it’d be the end of all of their brethren.

5/5

Not all individuals’ sails curve the same way, and that’s the magic of their body plans.

If you cup each of your hands in front of a powerful fan, each of your hands will be pushed out in a different direction. The same thing happens to the Man o’ War when a strong wind blows.

4/5

At the top of the Portuguese Man o’ War, there’s a sack full of air and carbon monoxide, which helps the Man o’ War float. And on top of this sack, there’s a crest, which can catch the wind and move the Man o’ War about as it hunts for prey. But if you look closely, the sail is a bit curved.

3/5

Like many animals that look like jellyfish, the Man o’ War is not a jellyfish. Instead it’s a member of an obscure order of organisms called siphonophores. In addition to their weird looks, siphonophores are colonial organisms, meaning they’re composed of specialized clones called zooids.

2/5

Further reading:
www.pbs.org/newshour/sci...

When the water transitions to steam, it displaces the oil above it, exploding dramatically.

While it makes for a sick science demo, that's probably not the kind of excitement you want at Thanksgiving, so maybe leave the explosions for the 4th of July and find another way to cook your turkey.

4/4

And that's where the magic happens, because water is more dense than oil. So the meltwater makes its way to the bottom of the pot, and then wants to evaporate into steam, which is more than 1,000 times less dense than liquid water and oil.

3/4