It's winter break here at Princeton High School (in Cincinnati, where you friendly, neighborhood blogger teaches), and that means a whole bunch of students hanging around at home in need of chemistry learning opportunities.
I'd particularly recommend making your own gel window clings (easy, kid-friendly) and the copper-plated Christmas ornaments (higher degree of difficulty).
I've made the ornamnets before, and they're a blast.
She's pretty lucky there that she didn't get a serious injury, admittedly.
But...
There's a significant mis-statement in the title of the video. The Coke bottle doesn't explode at all, not even a little.
What happens is that the liquid nitrogen poured into the bottle changes from liquid into gas. That's happening all the time at room temp. You have to store liquid nitrogen in what's called a dewar flask (the metal thermos that the 'scientist' is pouring from) because it insulates the liquid nitrogen from the heat of the surroundings, slowing down that process.
When the liquid nitrogen is poured out of the flask, it boils very quickly. When it boils, it changes from liquid to gas and expands drastically.
If there's nothing in its way, that expansion is no big deal. It pushes against the air; the air moves; all is well.
If you pour it on top of Coke, the liquid nitrogen (being less dense than Coke) floats and is open to the air. Again, no big deal.
If you invert the bottle so the liquid nitrogen floats upward to the sealed end of the bottle and has Coke below it, suddenly the liquid nitrogen is trapped. The expansion now has a problem because it has to push its way outward. In this case, the expanding gas pushes the Coke out of the now-upside-down bottle. According to Newton, every action (Coke pushing downward) has an equal and opposite reaction (pushing the bottle upward). Check out conservation of momentum if you have issues with that.
Because the Coke being pushed downward has mass and is moving, it produces force. Again, Newton F=MA. The plastic bottle has very little mass, so if an equal force is pushing the bottle upward, (equal F, smaller M) we get a much greater acceleration (A), so the bottle shoots upward very quickly.
As long as the bottle is flipped definitively and quickly...and it's pointed directly upward with nobody's face above it...it should be safeish.
The host didn't flip quickly. She paused because she was rightfully afraid.
The host didn't point the bottle directly upward. She rightfully wanted to move away, so she tipped the bottle and moved away at the same time.
Don't mess around with liquid nitrogen in sealed containers, folks.
See, it's funny because the phrase 'splitting the atom' often refers to nuclear fission, the literal splitting of the atomic nucleus, creating two daughter atoms from a single atom, typically converting a small amount of mass into a large amount of energy.
See, its funny because as the wavelength of light gets longer (from ultraviolet to violet on through the rainbow to red and infrared beyond that), the amount of energy transmitted per photon decreases.
Hence, an energy drink choosing to call itself RED Bull seems counter intuitive, I will admit.
I'm loathe to publicize something that was sent to me via spam email, but this one looks to be pretty good.
Verizon is hosting The Beacon, "Your source for technology & entertainment news and guides" (about as generic a description as can be corporate-spoken.) In one of The Beacon's nooks is this periodic table of technology with information on how most elements (90-or-so of them, up through californium) are used in producing the technology of our modern world.
It looks good, doesn't include any advertising or links back to Verizon or The Beacon, and each element's few sentences includes links to reliable, outside sources.
Gerry Dee is a Canadian comedian with a CBC show called Mr. D on which he works at Xavier Academy teaching...something.
Honestly, I've never seen the full show, just a whole bunch of clips on YouTube. From what I can tell he either teaches kindergarten or high school, gym or English or math. He also subs in other classes like shop.
Check out the clips, but don't necessarily rely on them for solid science knowledge.
My wife and I are trying to eat less meat. We're not going veggie or vegan or anything, but we know that our Western habits of eating big servings of meat every day and at multiple meals a day is horrible for our environment.
And if it takes eating 'meat' hamburgers like the Impossible Burger to eat a little less meat, I'll consider taking that hit.
No jokes here...this could just be a big deal.
Now, if I could just get it to be served somewhere closer to here than Texas and New York City.
The University of Nottingham chemistry department has a YouTube channel called PeriodicVideos. On the channel they have videos about every element on the periodic table and quite a few about other chemistry topics as well.
One series they have is slow motion photography of chemical reactions.
I've put my favorite up high, but the others are after the jump.
I love that these two (probably more, we see another guy filming things at one point) guys boiled water at all these elevations to see what the temperature of the boiling water would be.
Whenever in class we talk about the boiling point of water dropping in temperature as the outside air pressure dropped, I make up a number and say that water on top of Mount Everest boils at that temperature. In fact, I've never looked up the exact theoretical temperature. As far as I know, though, nobody has ever been to the top of Mount Everest and taken the time to do the actual experiment. That's mostly, though, because by the time you get to Mount Everest's peak, you're pretty much on your way to dying and every thought has to be focused on just trying to survive.
For explanation on why the boiling point of a liquid drops as the external pressure on the liquid drops, check out the follow-up video.
I've made and served Mock Apple Pie before, though mine didn't have the crumble topping like that shown up above. That's a nice touch and would likely make the whole thing a little more believable.
Admittedly, the texture is that of over-cooked apples rather than the ideally still-crisp apples in the best pies, but it's generally a decent 'apple' pie to serve. Proves that much of what we taste is based on a lot more than purely what we're really tasting. If the smell and consistency and look are all about right, we'll go for it.
6 - Maillard Reaction(s) - There are actually a whole bunch of reactions that fall under the umbrella of Maillard Reaction(s) so, the name should really be plural...There's also some idea that the Maillard Reactions produce some carcinogenic by products.
5 - Bronze - By all the definitions I've ever heard, alloying metals doesn't qualify as a chemical reaction. It's an important process, yes, but not necessarily a chemical reaction...Did he really say, "pokey sticks"?...sheesh...
4 - Fermentation - Again, lots of different chemical reactions coming under one big umbrella there...and there's no mention of the actual chemical reaction that takes place within the yeast and other microorganisms that actually do the fermenting.
3 - Saponification - This one gets the best explanation of the actual chemical reaction happening between the triglyceride and the base. Thanks...
2 - Silicon - Again, melting and recrystallizing anything isn't a chemical reaction...it's impressive and well worth studying, but it's misleadingly placed in this video.
1 - Haber-Bosch process - This one's massively important, agreed. Easily the best choice in the video. I'd put one other reaction above this one, but it's certainly not a modern one.
And the narrator's a little annoying...but that's sort of me being catty.
I am, admittedly, a big fan of Alton Brown's Good Eats. Nearly ever episode is an outstanding balance between science education and useful cooking knowledge.
In the episode above (illegally posted but available for $1.99 on YouTube (if you want to be honest and good), Brown goes through three varieties of chocolate chip cookies with just one change each.
Check out images of the many ways that cookies can be varied with just one little switch each at this link (without the science explanation)...
There are extremes of concentration and density that result in a far, far from homogeneous ocean bottom.
Above we see a brine pool, an area of ultra-high salt concentration that leads to a pool that is far more dense than the surrounding water and often contains high concentrations of methane, also, making the pool deadly for any animals that are unlucky enough to happen into the pool.
There are a bunch more brine pool videos from the Nautilus Live YouTube channel. I'll put a couple more after the jump, but they're certainly worth a hunt down.
