Whenever I get out of my house and it looks like this, I am slightly disappointed because it means that the wave watching that morning will not be ideal. I mean, I like colorful sunrises as much as the next person, buuuut…
Today, at least, the fog was kinda interesting, also because there was a large cruise ship driving through.
There was a low layer of fog, but look at what happens as the ship passes through: It lifts up! Visualizing the stream lines around the obstacle. Pretty cool! (And thank you, little police boat, for making at least some waves for me today!)
Even better visible below, but check out the smoke coming from the ship’s chimneys. Do you see how it is propagating forward? Or does it just look like that to me? At least below the fog layer there was pretty much no wind. So what’s going on up there? Anyone care to explain?
One of the most exciting things about work travel? Staying in tons of different hotels, which all have different opportunities to play with water.
For example at a recent team event, there was this tap with a really efficient aerator, that made the hydraulic jump look even more exciting than usual:
And then at a conference last week, this happened:
Can you see what happened? Obviously, I turned the water on, and the right side of the armature fogged up because of all the cold water going through! (Even though I can assure you: My shower was nice and warm!)
And I am not even going to apologise for how excited I get by observing these kinds of things. Remember the kind of tap I have at home?
So let’s start with fog in a bottle. I’m doing fog in a jar, because it is easier to balance a sieve with ice cubes on a wide-mouthed jar than on a bottle… There is about 2 cm of hot water in the jar and the sieve with ice cubes is put on top to cool the moist air enough for fog to form.
And now the cloud in a bottle. This one is fun! And a lot more impressive in the flesh than in the movie, so try it out yourself! Suck some smoke into a bottle that contains a little water. Close the cap, press and release the bottle and see a cloud forming when you release it. The smoke acts as condensation nuclei here. And pressure changes, temperature changes, yada yada… Anyway, try it yourself!
P.S.: Kristin – erkennst Du die Flasche? Die, die Deine Freundin Dir mitgegeben hatte, damit Du was zu trinken hast, die dann mit in Göteborg war und die ich dem Recycling zuführen sollte? Hat offensichtlich nicht geklappt, aber viele Grüße an Deine Freundin! :-)
When warm, moist air is advected and brought in contact with colder surfaces.
Recently I’ve been starting to think about a course I’ll be teaching later this year, and how it would be cool to have household examples for most, if not all, of the topics I’ll be talking about.
Fogged up bathroom window
So this is one example for advection fog: Warm, moist air moves against a cold window and condenses.
Of course you can also observe this over other cold surfaces, for example over the ocean:
In the movie below you can witness how the iceberg slowly vanishes as the fog closes in on the ship.
It can actually get pretty spooky.
On this picture you can clearly see that the fog is confined to a shallow layer directly above the ocean’s surface. We were standing on the deck above the bridge, and there we were up high enough to see that it is indeed a thin layer and that the skies above are blue. From the working deck it felt like fog had swallowed us up and the Black Pearl was about to appear…