Yes. Under the proper circumstances, you can heat a liquid to well above its boiling point without it boiling. Then even the slightest disturbance will cause it to boil in an instant.
One of my chemistry professors claimed he once accidentally did this with a microwave oven. He said he put a mug of water (evidently, very pure water) into a microwave and, unsure of the microwave's power, let it run for several minutes. He then tried to pour some cocoa powder in to make some hot chocolate, but it boiled over as soon as the first flakes of powder hit it, scalding his hand.
As an aside, it would rain and snow a lot less often were it not for dust particles in the atmosphere. Dust particles act as condensation nuclei for water droplets/ice. That's why "seeding" clouds with silver nitrate or other such chemicals will sometimes trigger rain.
Ironically, if the air is too clean, it can't rain or snow.
Cheers,
Michael
[ETA: Oops, too slow! ES beat me to it.]
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“The greatest way to live with honor in this world is to be what we pretend to be.”
In my Zoology class, I've been explaining about reproduction. I mentioned lizards of the genus Cnemidophorus in which no males are known to exist, yet the lizards nonetheless must actually go through the mating process in order to produce eggs. So, two female Cnemidophorus will take turns mating with each other, that each of them can produce eggs -- first one plays the "male," then the other.
Also, in explaining anisogamy, I quipped that "a sperm cell is just genetic material with a motor attached."
I heard later that the students have been enjoying telling "Dr. P" (one of the Chemistry professors) about the "lesbian lizards," "sperm as genetic material with a motor attached," and other such things they're learning in Zoology.
Cheers,
Michael
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“The greatest way to live with honor in this world is to be what we pretend to be.”
Here are a couple of neat videos illustrating supercooling and superheating.
In the first video, a bottle of water has been cooled to below its freezing point. Watch what happens when it's shaken. As soon as the guy shaking it agitates it enough to get an air bubble into the water, it freezes:
Yes. Under the proper circumstances, you can heat a liquid to well above its boiling point without it boiling. Then even the slightest disturbance will cause it to boil in an instant.
I accidentally made a coffee cannon this way. The cup that I was making foldgers crystal coffee (eww, I know) in was to tall to put in the microwave so I boiled a cup of water to poor in it. After forgetting it once I added time to it, took it out and dumped it into the tall slender coffee cup and boom out comes coffee all over the counter and the wall. Luckily it was pointed away from me.
When water freezes slowly -- as tends to happen when it's at or only a little below the freezing point, it tends to form sharp, needle-like crystals. Those will easily pierce cellular membranes and kill any organism that freezes slowly.
By contrast, when supercooled water freezes, it tends to form flat, hexagonal crystals that are much less likely to pierce and rupture cells. That's why you can drop a very small organism (say, an embryo) into liquid nitrogen and "instantly" freeze it without causing formation of the needle-like ice crystals that will rupture cellular membranes and kill the organism.
Some small animals actually take advantage of this phenomenon. Some insects can empty their "blood" (strictly speaking, insects don't have blood) of almost all "impurities" and then allow themselves to supercool. When they eventually freeze, the freezing happens so fast that the needle-like crystals don't form, and so the animal's cellular membranes aren't ruptured. When it thaws in the Spring, it's good to go.
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The way to supercool water is to purify it as much as possible (any impurities can form condensation nuclei), to put it into as smooth a container as possible, and to prevent any sort of disturbance. Sufficiently pure water in a sufficiently smooth container can be cooled to as much as about 40 degrees C below freezing without actually freezing.
You can do it in your freezer, if you're careful.
Cheers,
Michael
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“The greatest way to live with honor in this world is to be what we pretend to be.”
A number of videos I've seen are people that live in evil cold places (like up north in the US) and just leave the bottle out overnight or however long it takes the water to get below freezing.
I've tried it in the freezer but except for a few accidents I normally get a bottle of frozen water and not super cool liquid.
I posted a story in my blog yesterday about a block of beeswax from a 300 year old Spanish shipwreck that washed up on the Oregon shore. The article says that Spain had to import beeswax to the New World because there were no native honeybees.
Is that true, do you know? It boggles my mind because they're such an integral part of the ecosystem now that their recent mysterious decline has a lot of people dismayed.
There are some 20,000 or so species of bees, but the true "Honeybees" comprise just 7 currently-recognized species in the genus Apis. The genus appears to be native to southeastern Asia. The most commonly domesticated species is Apis mellifera, the Western or European Honeybee.
There are about 4,000 species of bees native to the New World, but honeybees aren't one of them. Since none of our native bee species have the favorable traits that honeybees do (living in large colonies that will produce economically-viable amounts of honey and wax, relatively benign temperaments), there's been no real effort to domesticate any of them.
The first honeybees were brought to the Americas in the 1600s. Since then, they've become quite important in North- and South-American ecosystems, though that's not entirely a good thing. Many of our native flower species evolved to be pollinated by native bees, and cannot be pollinated by the non-native honeybees. That wouldn't be a problem, except that our native bee species have been devastated, and many are in serious danger of extinction.
Between losing most of their habitat to agriculture and other human activities, being killed by pesticides, and competition with the non-native honeybees, a great many of our native bee species are in serious trouble. This is a matter of considerable concern not just to entomologists and ecologists, but to lovers of our native wildflowers. There are efforts to try to preserve habitat for native bee species, and one commonly-cited reason some people encourage "natural landscaping" and planting of wildflower gardens is to help preserve native bee populations. The Xerces Society is an example of an organization dedicated to educating people on the value of native invertebrates, and to promoting conservation of native bee species.
Cheers,
Michael
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“The greatest way to live with honor in this world is to be what we pretend to be.”
Fascinating, Michael, thank you. I've been lumping all bee species together, I see. I'd love to have a native flora garden. Not only do the plants provide for local creatures, vertebrate and non, but they require much less maintainance and watering, something that's hugely important right now in my droughty neck of the woods.
thread bump for another episode of, Ask the Lone Ranger.
My friend found this plant at a local farmers market and no one can seem to tell her what it is, combined with many of the growers not speaking much english has left her perplexed. The pods have a raddish like taste,
Looks like Guatemalan Insanity Pepper to me. Or, at least, that's always what I wind up with when I buy vegetables I don't recognize form non-English speaking strangers.
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"Trans Am Jesus" is "what hanged me"
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"God is no longer an explanation of anything, but has instead become something that would itself need an insurmountable amount of explaining."
- Douglas Adams