True Facts Water Walkers: Educational Edition

If you've watched any of the True Facts videos before, you might be a little leery of my posting of the videos. They have historically used some adult jokes to keep viewers interested along the way.

The newer TrueFactsEducational channel, however, keeps the jokes no worse than PG meaning that they're okay to watch - at least in a middle- or high-school setting - which is awesome because the information presented about how water striders - and spring tails - walk and move on a surface of water is excellent and entertainingly presented. 

How Plastic Made With Algae Can Clean Waterways | World Wide Waste

The World Wide Waste series from Business Insider is rich with material science content. You'll be seeing most of their videos on the blog eventually, but I certainly recommend watching them before that.

This video explores a project to jointly clean waterways prone to algal blooms and produce plastics which can then be used to produce whatever plastic products would normally be made from many plastics.

Anything that replaces some of our oil-based polymers - even if it's not replacing 100% of the polymer - is a good thing. I appreciate that the latter half o the video explores some of the more complex aspects of this issue - trapping carbon dioxide in plastics isn't the final answer because it still creates more plastics, the causes of the algal blooms, the environmental costs of shipping the algae and products across the oceans. 

It sounds like this is a better option than plastics but that it's not perfect. 

Small steps add up, I guess.

CERAMIC COATING - How It Works | SCIENCE GARAGE

First off, thanks to Eric Moorman who sent me this video. Mad love for Eric.

Let's go through the material science awesomeness in this video about how to get the most durable, prettiest finish on your car.

• The first four minutes or so are all about the causes of the tiny scratches on car surfaces and how to clean the car before applying a finish coating of either wax or ceramic.
• At 4:10 we get a discussion of wax, and the host even uses the word hydrophobic, explaining how the water beads up because of the hydrophobic nature of the wax.
• At 5:10, we finally get to the ceramics, "a non-metallic solid material making up an inorganic compound of metal and nonmetal (or metalloid) atoms primarily held in ionic and covalent (?) bonds." The host explains that those atoms can be crystalline (in various ways) or even vitrified.
• There's an explanation of the Moh's hardness scale, and a mention that there are other ways to measure hardness like via measuring scratch resistance.
• Heck, he even shows a very simplified version of covalent bonding with shared pairs of electrons.
• We get into using nanotextures to increase the hydrophobic character of a surface, increasing the contact angle between a drop and the surface - with a nice diagram, too - explaining super hydrophobic coatings.

Admittedly, I had no idea such coatings existed for cars.

This improbable membrane can trap flies in a jar - and odor in a toilet

Well that's just cool.

The membrane described above can block small particles but allow larger particles through, a thoroughly non-intuitive method of filtering.

Then again, water is weird. It holds together, 'healing' itself via intermolecular forces. In this case, the addition of sodium dodecyl sulfate - something I've heard called sodium lauryl sulfate - allows the water membrane to be penetrated and then come back together.

In order to break through the membrane, particles need enough momentum (mass times velocity, natch) to break through the membrane, so larger particles have an easier time to get through. Smaller particles, then, have to be moving far faster if they're going to break through.

And automatically, people go straight to the possibility of keeping the poop smell in a toilet.

Because everyone poops.

You Can Hear The Difference Between Hot and Cold Water

The title of the video, "You Can Hear The Difference Between Hot and Cold Water," is clearly wrong and stupid.

There's no way that you can hear the difference between hot and cold water at all.

Except that the video makes clear that you can...because of viscosity.

Modified sponge mops up oil but not water

"Due to the nature of the industry, cost-effective high absorbents are needed...Any advancement to have high spill sorbent is of use." ~ Seshadri Ramkumar

See, what he's saying is that the oil industry (and the shipping industry and pretty much everybody else) spills oil in the ocean...and lakes...and rivers...and fields...so we need to be ready to soak up the oil.

The environmental impact and morals of our modern dependence on fossil fuels aside, the chemistry here is pretty cool.

Though the name of 'compound 1' seems a little odd to me because I can't imagine that the first compound they tried was their successful attempt. There's a reason why we have Formula 409.

Molten Aluminum vs 'Spitballs' - SO COOL!! (water balz)

I'm starting to recognize that the danger in molten metal coming into contact with water is when there's a small amount of water.

That small amount of water can gain enough energy to boil which spits the molten metal into the air.

Dump the same molten metal into enough water that the water can't all boil, however, and some cool stuff can happen.

chemed 2013 diy chemistry

Alfredo Mateus is apparently pretty cool - or at least has some pretty cool ideas.

Through the Prezi above first, largely without words...

• The bottle tops - hacksawed off just below the screw top collar - become flexible in hot water and can be turned into keychains. The distorted bottle tops then can show the thermoplasticity when returned to hot water.
• The inflation of the preforms is a bit trickier, and the method hinted at in the Prezi is far tougher to pull off. Check out my other post about a way to successfully inflate the preforms.
• Carving a can with chemistry is a variation on the aluminum can demo using a solution of either sodium hydroxide or copper (II) sulfate to react away the aluminum can. Here Mateus has used this to produce some nice lights.
• The hydrophobic toys need a whole lot more explanation. The carbon compounds in soot are apparently hydrophobic and can make for a very cool 'maze' by letting the droplets roll around rather freely.
• The PET molecules, though, are pretty spectacular, and they're the ones I desperately want to recreate for my classroom. I just need to figure out how to throw around a few pop rivets. And sadly, they're the only ones that are NOT covered in the related pdf of instructions.

Any chance anybody can find better instructions for the 2L bottle molecules?

Material Uses Insect Technology to Stay Dry Under Water

Let's start with the basics, shall we?

In general water is bad for the long-term durability of most surfaces - especially metal surfaces.

Water molecules hold together pretty well. I've even seen (and highly endorse) magnets that show this.

Water molecules have some volume, especially when they hold to other water molecules.

(Now, the tougher step...)

If you can make bumps...pores...posts...something on the surface of a material that leaves spaces too small for water drops (clumps of water molecules) to go into, the surface of the material will stay dry.

Seriously...like forever dry...not from a coating that will eventually wear off...permanently dry (or at least for four months as the early research shows)...

Left column: (top) Polymer/HFS (NC1) composite coating on aluminum substrate, (bottom) silicon square microposts. Middle column: (top) zinc oxide nanorods on silicon substrate, (bottom) silicon nanowire forest. Right column: (top) silicon microgrooves, (bottom) silicon nanograss.

See those scanning electron micrographs (SEM) above? They're from an article on Nature's website. Each surface was tested to see how long it would resist being wetted when immersed in water (then in water that had been thoroughly degassed - to make sure it wasn't gas bubbles being trapped that resulted in the lack of wetting).

Left: Wetted surface with 25 μm pillar spacing. Middle: Wetted surface with 5 μm pillar spacing. Right: Dry surface with sub-micron pillar spacing. Abbreviations: Frozen water (H₂O), Silicon substrate (Si)

And there you can see their results. Make the pillars wide enough to leave 25 microns of space, get a wet surface...5 microns, still wet...less than one micron, dry...forever dry...perfectly dry.

There's a nice summary of the article on IFLScience's website, but you do, as always, run into the issue of that F in the web address...

Rocket Under Ice

In general, I wouldn't post anything this stupid (there are exceptions, natch), but the shattering of the ice from the underwater bottle rocket explosion is just so darn hexagonal, breaking as it does, I assume, because of ice's hexagonal crystal structure.

The SECOND Official Ultra-Ever Dry Video - Superhydrophobic coating - Repels almost any liquid!

The look on the face of the Ultra-Ever Dry shirt-wearing guy is priceless (at about 3:20 and onward).

And, honestly, if you have to wear a shirt and tie while running the risk of being mud-bombed, you might want to spray the heck out of your clothes before heading into the fields.

This video gives us some entertaining and impressive demonstrations of ultra-ever dry on notebook paper, ceramic tile, a digital stopwatch, tissue paper, tissue paper (with a thoroughly gross ketchup demo), bread (no, don't eat the bread afterwards), cotton ball, and finally an explosion of mud.

Rain works

How cool is that? It rains, and 'magically' a design appears on the cement. Maybe it's a hopscotch board (is that the right term, is it a board, Google suggests that it's a board, anyway), maybe it's a reminder to save water, maybe it's a chucklesome commentary on the weather.

In the Tacoma, Washington-area (check out the specific locations on their website), a group of guys from Peregrine Church are using Nanex's Always Dry to spray on superhydrophobic coatings in fun designs. They're calling their program rain.works. Check 'em out.

Heck, make one yourself in your town. Apparently it's legal, "as it’s temporary, which it is since the messages come and go, and isn’t commercial."

Staying dry in a world covered in water

The opening gif of the water droplets bouncing cleanly off of the surface of the laser-etched metal is mesmerizing. (check the linked article to see what I'm talking about, Blogger doesn't allow for easy embedding of animated gifs, sadly).

We talk in chemistry class about materials being hydrophobic or hydrophillic because of the molecule's polarity. Polar things, see, will dissolve (or at least attract to) equally polar things. Non-polar things the same, as well.

But then you get to the weirdness that is nano-texturing, and all that polar or nonpolar stuff goes right out the window. It's such an odd thought to understand that macroscopic properties have little to no effect on the nano- scale.

But it's really cool to read about.

Molasses in January is no longer slow with LiquiGlide

That is a really slick demonstration.

Get it? Slick?

Admittedly, the molasses is dark and might have shown up better against a light-colored coat.

I tagged this post with superhydrophobic, but the article from iflscience (I wish they would change their name to something most school-appropriate) says very specifically...

While the coating appears to be similar to superhydrophobic surfaces that are already in use today, the technology is different. Superhydrophobic surfaces repel water by creating a layer of air between the water and the rough surface. The technique is used for a variety of products, but there are some drawbacks with durability.

However, where superhydrophobic technology uses air, LiquiGlide uses liquid. The founder calls it a “liquid-impregnated surface” because the liquid fills in the gaps between the textured item. The coating can also be adjusted depending on the material, making the range of possibilities immense. Just this week, the company teamed up with Elmer’s Product Inc. to use the technology for their glue bottles.

Wild, man, wild.

And LiquiGlide has a BUNCH of videos showing their coating in bottles with different liquids.

Aluminum Thermal Explosion

And that, my friends, is why you always need to keep your mold totally, absolutely, perfectly dry when you're pouring molten metal. Steam explosions suck.

This is not something to laugh about...unless you're Russian, I guess.

Super Hydrophobic Surface and Magnetic Liquid

The Slow Mo Guys make videos showing actions in - shockingly, I know - slow motion.

Here they're in a GE lab showing 'how water reacts on a superhydrophobic surface,' in their words. Personally, I'd've liked to have seen a single drop on the surface, but the beauty of the two differently-colored streams coming together and showing almost no interaction with the white surface is pretty cool, too.

The last part of the video also shows a ferrofluid attracting to a magnet.

Water and Solutions -- for Dirty Laundry: Crash Course Chemistry #7

Thank you, John Green.

This thirteen-and-a-half-minute-long video covers enough chemistry about water that if my students understood the entire video by the end of my year of chemistry, I would be pretty happy.

Because it's that saturated with knowledge, I don't know that I'd necessarily show it in one sitting in the classroom. It's dense, man, but it does a spectacular job explaining (and showing via animation) a whole lot of ideas about the chemistry of water. I'll list some of them...

• oxidizing (like bleach and hydrogen peroxide do)
• solutions (aqueous ones)
• solute
• solvent
• polar molecules
• polar and nonpolar molecules dissolving each other
• water dissolving ionic compounds
• electrolytes
• strong, weak, and non-
• moles
• concentration
• molarity
• molality 
• diluting

Copper In Our Electrical World

I'm thinking that there is a better way to take those electronic devices (2:30) apart than just bashing at them with various hammers. Maybe I'm wrong, though.

I'd never really thought about the process through which copper deposits are made, and this video covers the chemistry from 3:30-5:00. From there we get to follow the copper from deposit to purified copper - through hydrometalurgical processing (purifying the copper via aqueous solutions - 5:15-8:30) and pyrometalurgical processing (heat, smelting - 8:40-11:30). The level of detail in each process is marvelous as are the animations used to show what happens in each step along the way. We even get a discussion of hydrophobic and hydrophilic effects at 9:30.

I had no idea of the numerous steps along the way from ore to pure metal.

The video moves onward to (11:40- ) to an exploration of why copper is used - relatively low cost, good conductivity, durability - so commonly throughout our industrial world. These properties are explored through the crystal structure (grains, boundaries, etc) of the copper crystals.

From 13:40 onward the uses of copper - wires, electromagnets, antennas and wireless, integrated circuits - are covered.

The video is a little long, but there is a degree's worth of science covered in the eighteen minutes here.

Water is a pretty awful material for building. Yes, it's abundant and cheap. Yes, it can be made opaque or translucent or even pretty transparent. Yes, you can use it to make buildings (like in that totally awesome James Bond movie), but there are a few drawbacks.

It's slightly unstable in the warmer climates. It's vulnerable to destruction from dogs marking the walls. Ice chairs make your hiney all cold.

So this video isn't really about materials, but it is a great background video on the chemistry of water, something that most of our materials run into from time to time.

The chemistry explanations are fairly in-depth (electrolytes, polarity, moles, molarity, anions, and such), so this may not be for all of your students, but it's a great bit if chemistry.

Mark Shaw: One Dry Demo

The above TED talk isn't bad, though it does sort of make Mark Shaw, the co-president of UltraTech (according to this page on their site), look a little nervous throughout. He should relax, though, because he's got a heck of a product: Ultra Ever Dry. The coating creates a superhydrophobic surface (check 1:15 in the above video for a scientific explanation of what superhydrophobic means) that's apparently also oleophobic, meaning that the coating will repel water and oil, a pretty spectacular combination.

The first video below shows the coating in action with the best payoff (for me, anyway) being the green square of liquid on the glass (shown above at 2:50 but in much higher resolution below). Seriously, many of the demonstrations go so far against what I expect water to do that they look almost like bad computer animation, actions that my brain openly repels against.

I have to get some of the coating for myself to test. If only the coating wasn't about $200 for their smallest size can (plus spray bottles to apply).

I do wonder whether the final demonstration - the one with the TED sign - was tested first. It's a a great demo, but the timing is disappointing.