I ran across an archaeological discovery where cheese-making was confirmed 7,000 years ago.
I'm sure most people know that cheese is an old-fashioned, pre-refrigeration way of preserving milk. It's a pretty interesting preservation method, because it involves a specific kind of bacterial growth—and bacterial growth is usually what's involved in things going bad. I started to wonder: how did people figure out that if you let milk rot in just the right conditions, it doesn't actually rot but turns into cheese?
Which bacteria grow depends a lot on the conditions. With specific nutrients and temperatures, certain bacteria will come to dominate. Sort of like with my home bioreactor, I kept the conditions right for the bacteria I wanted to dominate.
To my surprise, this one turned out to be quite easy, and not as much of a stretch the way chocolate was.
You know how last week I said I'd post something short and easy? Well this is it.
Two places to get general continuing education, which I have been enjoying for some time now:
The Khan Academy, free bite-size videos, usually in the 10-minute range, and exercises to practice what you learn, all free. It's heavily weighted toward math as that's how the whole thing started, but with quite a few other subjects as well. The site also has badges you can win if you like that sort of thing, and you can track your progress through the videos and exercises. You don't have to start at the beginning; I jumped into calculus and linear algebra because I wanted to refresh both of those. (The majority of the math I do at work doesn't use either of those, so I was way out of practice.)
The Teaching Company, multi-lecture courses on a wide variety of subjects. The courses look very expensive, but if you find one you want, just wait for it to go on sale. Everything goes on massive discounted sale at some point during the year, and a lot of the stuff I've looked at goes on sale in the under $40 range for audio-only download. (They also do video download, and CD/DVD shipping for audio/video respectively, as an option for the majority of courses. Those tend to be more expensive.) For 12 hours of audio lectures given by a noted expert in the field, I think it's a pretty good price. (But if you want math, go to Khan Academy. You can't beat both free and fantastically clear explanations.)
I hope some of you find those resources useful.
Well, that ten-post greenwashing series was a bit more work than I had anticipated, but interesting. I learned a lot, so I think that makes it worthwhile. After all, that is the point of this site!
I noticed some common threads running through nearly every item on the Marketplace list, which I've also seen and heard elsewhere. The main one is a fundamental misunderstanding of chemistry. I've lost count of how many times I've heard people in other context using "chemicals" as a blanket term for something bad. It's as if they don't realize that water is a chemical, vitamin C is a chemical, every micro- and macro-nutrient in food are chemicals, everything made of matter—beneficial, harmful, or neutral—is made of chemicals.
And they probably truly don't realize it.
Being a chemical engineer I've been so immersed in chemistry I sometimes forget that after about grade ten general science class, chemistry of any kind becomes optional. A lot of people, probably most people, don't take chemistry and don't have anything more to do with chemistry after that—sometimes to the point of not knowing the difference between an atom and a molecule.
Unfortunately, this seems to lead to a fundamental misunderstanding of what is natural and what is healthy—and what is environmentally friendly. In turn, that makes it really challenging to make informed decisions on those subjects.
At this point, I should probably reiterate my disclaimer from the first post, lest somebody claim a conflict of interest in my interest here. I have no connection with any of the companies or products listed in this series. I don't work in household products at all, in fact. I spend my days doing industrial scale environmental cleanup type work—mostly prevention lately, but I have done remediation as well. I'll also add that if some new, quality research comes to light that contradicts any of my conclusions in the previous ten posts, I'll update the relevant post accordingly as soon as I learn about it.
I'm actually more disappointed in Marketplace than I am in most people who don't understand these things, for two reasons. First, Marketplace probably has the budget to find a good expert to help them and their viewers understand this stuff—and if they don't know where to look, then they should go ask their colleague Bob McDonald: that guy has a team that can find experts in fields you didn't even know existed, and he's really good at explaining things. Second and more importantly, Marketplace have a good reputation for exposing actual problems. I had expected a higher level of accuracy from them, as well as a lower level of gullibility.
As I mentioned last week, Marketplace is a 22 minute show and they did a 10-product countdown, giving them approximately 2 minutes per product, so they had to leave a lot of information out. And hey, I don't have the format restrictions, so here's a bunch more information than they could possibly fit in.
So, product claims. It's a Dawn product, which means it's marketed as a grease-cutting dish soap that's gentle on your skin. This particular Dawn product is the only one on their website which is specifically marketed as antibacterial. It has a picture of ducks and says "Dawn helps save wildlife" on the label, also the only one shown on the website with this labelling. Their Saving Wildlife page lists two US organizations for marine animal rescue, one for marine mammals and one for seabirds, which they donate money to. They also donate dish soap to wash the birds soaked in oil. (Interestingly, the US version of the website doesn't show the ducky label, even though the organizations they support are based in the US.)
Marketplace claims that Proctor & Gamble (owners of the Dawn brand) are making a big deal out of helping wildlife while at the same time putting the ingredient triclosan in their soaps, which Environment Canada has declared toxic to aquatic wildlife, and which (unnamed) environmental groups have called for to be banned. The expert also says that it washes down the drain to the wildlife and builds up in their systems.
As I mention each and every week, Marketplace is a 22 minute show and they did a 10-product countdown, giving them approximately 2 minutes per product, so they had to leave a lot of information out.
So, what does J-Cloth claim? Apart from being a re-usable, machine-washable, lint-free paper towel replacement, which they've established a long time ago, J-Cloth claims that its biodegradable offering is fully biodegradable, because it's made from biodegradable fibers. When called by Marketplace, they said that the fibers were cellulose from wood pulp. Unfortunately, their website doesn't seem to have any further details that I could find—and cellulose can mean a lot of things, from cotton to rayon to paper, all of which are biodegradable.
Marketplace says the biodegradable seal on the package is invented and doesn't represent any certification mark, and is there to "look official". When they asked the company, the company said that J-Cloths could go in a municipal green bin for compostable waste. The critic says J-Cloths are not certified compostable and so the city compost teams will pull it out and divert it to the landfill, and landfills are designed air tight and water tight and basically, nothing ever composts in them.
As I mentioned last week, Marketplace is a 22 minute show and they did a 10-product countdown, giving them approximately 2 minutes per product, so they had to leave a lot of information out.
So, the T-Fal website claims for the Natura line that it's made from 100% recycled aluminium and the non-stick coating is PFOA-free, lead-free, and cadmium-free.
Marketplace says that PFOA is still used in the manufacturing process, and that it always has been not present in the final product, and that it likely causes cancer as well as being widespread in the environment. Also they acknowledge that 100% recycled aluminium is a good, environmentally friendly thing.
For the Fallen by Laurence Binyon
With proud thanksgiving, a mother for her children,
England mourns for her dead across the sea.
Flesh of her flesh they were, spirit of her spirit,
Fallen in the cause of the free.
Solemn the drums thrill; Death august and royal
Sings sorrow up into immortal spheres,
There is music in the midst of desolation
And a glory that shines upon our tears.
They went with songs to the battle, they were young,
Straight of limb, true of eye, steady and aglow.
They were staunch to the end against odds uncounted;
They fell with their faces to the foe.
They shall grow not old, as we that are left grow old:
Age shall not weary them, nor the years condemn.
At the going down of the sun and in the morning
We will remember them.
They mingle not with their laughing comrades again;
They sit no more at familiar tables of home;
They have no lot in our labour of the day-time;
They sleep beyond England's foam.
But where our desires are and our hopes profound,
Felt as a well-spring that is hidden from sight,
To the innermost heart of their own land they are known
As the stars are known to the Night;
As the stars that shall be bright when we are dust,
Moving in marches upon the heavenly plain;
As the stars that are starry in the time of our darkness,
To the end, to the end, they remain.
The last veteran of World War I died since last year's Remembrance day, in February 2012. Joined months before the war ended and never saw combat, but all members of the military are veterans.
The last combat veteran of World War I died the year before, in May 2011.
Now the only people left who remember those years are the children who were too young to serve.
We, who were not there, are all who remain to hold the memory.
Vimy Ridge Memorial, Arras, France. (Veterans Affairs Canada)
As I mention each time, Marketplace is a 22 minute show and they did a 10-product countdown, giving them an average of 2 minutes per product, so there's only so much they can cover. I'm filling in with a bunch of stuff they couldn't have shown even if they wanted to, consisting of whatever I find that I think is relevant. Not having a 2-min time limit is handy that way.
So, the Organic Melt ice remover product brochure says that it's 100% natural, gentle on concrete and plants when used as directed, and a few other things that speak more to its effectiveness than its eco-friendliness.
Marketplace says (on asking the manufacturer) that despite the label claims, the product is only 3% organic (beets) and the rest is rock salt.
(At this point I'd like to draw your attention to the fact that rock salt is perfectly natural. If there were any above-ground rock salt deposits left (those that haven't dissolved in the rain have already been harvested) you could walk up to one and bash some rock salt loose for yourself. It's just not a plant, which is what a lot of people seem to mean when they say something is "natural".)
The Organic Melt MSDS lists the two ingredients (NaCl, aka rock salt; sugar beet extract) but doesn't display the percentage of each. The "synonyms" and "chemical class" sections, however, do acknowledge that it's mostly salt.
As I mentioned every week, Marketplace is a 22 minute show and they did a 10-product countdown, giving them an average of 2 minutes per product, so they had to leave a lot of information out.
Vim PowerPro is, according to the manufacturer's product page, "made with 98% naturally derived ingredients including fermented citric acid."
Marketplace says that the word "natural" is totally unregulated, and without an ingredients list, they can't know what that 98% natural claim actually means.
As usual, I went looking for the MSDS, but couldn't find one online. Marketplace says they asked for an ingredients list and got "only" an MSDS, which isn't an ingredients list. Funny, that's where I've been getting my ingredients lists for this series. Wish they'd posted it. It is possible that the Vim MSDS contains only the chemicals regulated as hazardous, which is what the law requires. Most companies (whose MSDS's I've seen) put all ingredients in the list, although I have seen some with only the regulated ingredients.
So, no MSDS for me, and no ingredients list either.
But—I did eventually find a candidate for an ingredients list.
As I have mentioned each time, Marketplace is a 22 minute show and they did a 10-product countdown, giving them an average of about 2 minutes per product, so they had to leave a lot of information out. This series is me looking to see what other information is out there.
The Eco Collection bath mitt is, according to the manufacturer's product page, a natural bamboo fiber and natural cotton product. They claim antibacterial properties for the natural bamboo fiber, and that it's made using rayon from bamboo.
Marketplace claims that bamboo can be grown sustainably but requires "funky chemical processing" to make a nice soft fiber, and the product package is unrecyclable vinyl.
This may well be the shortest segment they did of the ten—basically saying the above, then moving on. (I didn't time the segments.)
So, I'm going to look at exactly what's so "funky" about the chemical processing required to turn bamboo fiber into rayon.
Science makes yet another super-interesting discovery that started from a "wait, that's weird" moment. One which was initially misinterpreted, too.
So a while back there was a big splash in the news about some bacteria which had been isolated from a lake that was quite high in arsenic, where said bacteria—and other creatures—were thriving despite the arsenic.
It wasn't just that the bacteria could live in an environment containing arsenic, as there were already known bacteria which "breathe" arsenate; it was that the initial tests seemed to show that the bacteria could grow in the absence of phosphate, by substituting arsenate for phosphate.
This last conclusion turned out to be incorrect. However, the bacteria could still thrive in lab environments where the phosphate to arsenate ratio got completely absurd—as long as there was a trace of phosphate there. That in itself was pretty strange, because arsenate is a deadly poison.
As I mentioned last week, Marketplace is a 22 minute show and they did a 10-product countdown, giving them approximately 2 minutes per product, so they had to leave a lot of information out.
So, first things first: the Simple Green MSDS.
As I mentioned last week, Marketplace is a 22 minute show and they did a 10-product countdown, giving them approximately 2 minutes per product, so they had to leave a lot of information out.
Interestingly, when I went to the ObusForme website to see how they were promoting the EcoLogic pillow, I couldn't find it there. Looking a little closer, Marketplace contacted the manufacturer to see what they had to say about it, and it turns out the EcoLogic line is no longer being marketed in Canada.
Oh, Marketplace. Why would you pick a product that isn't even being made anymore? Surely there are products still being actively marketed that are deserving of your "lousy label" sticker.
Oh well. Might as well look at it anyway. I don't know much about memory foam, and why pass up a chance to learn something new?
As I mentioned last week, Marketplace is a 22 minute show and they did a 10-product countdown, giving them approximately 2 minutes per product, so they had to leave a lot of information out. I am the CC so I am filling the (chemistry side) gaps, to satisfy my own curiosity.
As always, I start with the MSDS to get an ingredients list.
Just this past weekend, CBC Marketplace did another one of their consumer product reviews, digging into the reality behind the marketing claims. This one is of special interest to me, because I'm both a chemical engineer and and an environmentally conscious person, and it demonstrates pretty clearly why a lot of people believe that combination isn't possible.
This episode was titled Lousy Labels: Home Edition (video, 22 minutes; text summary of their findings) and tackled "greenwashing", or overblown claims of being environmentally friendly, specifically on household products.
Since it's a 22 minute show and they covered ten products, that leaves about 2 minutes per product. There's a lot they had to leave out to fit inside that time limit.
So, because I am interested in learning, interested in being environmentally friendly, chemically inclined, and perpetually looking for something interesting to write about, I decided to take a closer look at these products.
Oh, and since I'm a chemical engineer and some people will be suspicious of me because of that, I will state up front that I have no relationship with any of the chemical products or companies talked about in this show. I don't do consumer goods, I do industrial scale environmental cleanup type stuff.
I'll do them in the same order that Marketplace did, which means I will start with #10: Raid EarthBlends Multi-bug Killer.
The last step in production from my home bioreactor is to heat the mixture to a specified internal temperature, about 95-98C. The first few times I tried, I followed the instructions exactly and it worked great.
Then I decided that the final shape of the product when following the instructions was not as convenient to me as I would like. Using a different shaped container was in order. However, this different container was not only a different shape, it was not conducive to pre-heating and had nowhere near the capacity for storing heat and holding its temperature as the original, inconveniently-shaped container did.
I tested it out anyway, and while it did produce a final product of about the shape I wanted, the characteristics of the material in the centre had changed. It was usable, but not as easily so. I eventually figured out that it hadn't heated up right through as it should have. I tried heating it for a slightly longer period, but that didn't seem to make much of a difference.
Trial and error will take far too long. Clearly, this calls for some math.
A day to acknowledge labourers, in which people with office type jobs get a day off work and sleep in, but labourers in industrial or service type jobs don't.
Yeah, no post today. See you next week. I promise math next week :-)
Looks like computers are opening up even more areas of chemistry!
Earlier this year I posted about some software that can predict crystal growth conditions.
Organic chemistry isn't my field, so unlike the crystal software I probably won't be able to justify a purchase to my boss, but I can still think that this is pretty amazing. The researchers spent a good solid ten years putting the sum total of all organic chemistry knowledge from the past 250 years into a database.
Not only can the computer search possible reaction pathways to make whatever compound you want, you can also filter those results. For example, pathways that use only non-toxic ingredients, or pathways with fewer reaction steps.
In one excellent example, the software came up with what they're calling a "one-pot" reaction for an asthma drug, which is normally produced with four separate reaction and separation steps. The suggested one-pot reaction said that they could put all the ingredients in the same flask in a specific order with specific timing—but with no separation steps, which are often complicated and expensive—and get the asthma drug they wanted—so they tried it.
This software sounds like it can lead to the truly ideal case that chemical engineers wish for: faster, cheaper, and safer all at the same time. There are a lot of reactions that use dangerous chemicals, because we don't know of alternate reactions to produce the same thing. Sometimes, research eventually reveals an alternate; for an inorganic example, the production of sodium hydroxide used to involve mercury, which is very toxic even in very small amounts. Now, the mercury process is rarely if ever used, because better and safer processes have been found.
One thing I've complained about many times in the past with respect to internet searches is the way blogs will link to the blog where they found a link to something interesting, not to the something interesting itself.
I understand the desire to acknowledge the source of your information, and kudos to them for doing so. But from the point of view of somebody searching for information, what this means is that a google search will find a lot of blogs talking about this cool thing, all linking to each other in a long chain of clicks which is sometimes broken in the middle by a blog being long abandoned and taken down. This happens often enough that it has its own term (linkrot) and it makes it very hard to follow the clicks to the "something interesting" you're looking for. (This has been improving in the last few years, fortunately; either people are getting better at linking to both the original and their source, or google is getting better at filtering out the link chains in their search results.)
But, like everything on the internet, this is just a computerized, digitized version of something that is not new at all, as I have been discovering since starting this blog a bit over a year ago. I saw a perfect example of it while doing the reading for an earlier post, in fact, though fortunately (this time) not the linkrot aspect of it.
One paper I read made a claim, and had a citation for it. I searched Google Scholar for the paper cited, found it, and looked for the information to back up the claim. Instead, I found the exact same claim, using almost the exact same phrasing, with a citation listed. So, after shaking my head in mild disbelief and wondering if the author was just copying without verifying, I searched for this other citation. Fortunately I did eventually find the original paper, and it did say more or less what the cite-upon-cite said.
I've run across the term "double-blind studies" in reference to medical research. In the operations and research that I've done myself, I've made use of "blind testing" as needed. It is widely considered both in medicine and in my own field of chemistry to be the most accurate way to get results uncontaminated by our own wishful thinking.
I wrote earlier about the placebo effect, and blinding the studies is probably the best way to counter it.
In chemistry, we really only need single blinding: the person running the lab tests doesn't know what the sample is supposed to be: a sample, a duplicate, a standard, or a blank. To do this, I hand over a set of sample bottles with nothing but code numbers written on them and tell them to test the lot for a particular set of compounds. A chemical reaction is a chemical reaction; if the same sample doesn't react the same way to the same test, it means somebody did something wrong somewhere along the way. In medicine, it's not so easy because there are patients involved, and their reactions (chemical, biological, and psychological) are all slightly different, and some of them will get better on their own no matter what is given to them.
Once again, there are two rovers alive and well on the surface of Mars.
Just over eight hours ago, Curiosity landed on Mars. It was an odd mixture of tension and knowing that no matter what we saw, it was all 14 minutes in the past and there was absolutely nothing anybody could do.
Two rovers? You haven't forgotten Opportunity, have you? Eight and a half earth years old (five martian winters) and still going strong.
Not too long ago, a picture from the world's most sensitive atomic force microscope was published, which showed the internal structure of a fairly small organic molecule: a 5-ring snippet of graphene, which is currently a hot and sexy topic in carbon chemistry.
The AFM in question has a sensor "needle" made of a single carbon monoxide molecule, and it's small enough to measure the gap in the middle of a six-carbon hexagonal ring structure, of which olympicene has five.
Will olympicene be a useful compound? I don't know. It's one of a class of potentially useful compounds. Even if it turns out not to be useful itself, learning how to control the reactions to create it is useful in learning how to create other molecules, and learning how to get a clear image of it is useful in learning how to get clear images of other molecules, so we can directly see what shape they are.
And here's an interview with the people who made it:
While looking up information on how ammonia takes the sting out of stings, I ran across two studies, both double-blinded, placebo-controlled trials of a sting relief formulation. The one that mentioned ammonia was the one I read first, because that's what I was looking for. The other one named a product brand name I'd never heard of before; I read it by accident, clicking on the wrong link in the search results. These two trials came up as the top two results when I searched google scholar for ammonia mosquito bite relief.
The two studies are: Effectiveness of Ammonium Solution in Relieving Type I Mosquito Bite Symptoms: A Double-blind, Placebo-controlled Study and The efficacy of Prrrikweg® gel in the treatment of insect bites: a double-blind, placebo-controlled clinical trial.
Go ahead and read only the abstract; those are all I'm going to talk about, not the rest of the papers. The abstracts say it all.
The chemical I want to talk about today is a widely used and very useful chemical called N,N-diethyl-3-methylbenzamide. Most people know it by its acronym, DEET.
I was recently wondering just how DEET does its thing of making mosquitoes not bite people. (Why yes, the recent gap in my posts means I was on vacation. There may have been mosquitoes involved.) Obviously, I started by searching Google Scholar.
I ran across yet another news item about processed food the other day, and decided to find out a bit more about what was behind it.
For those who didn't click the link above: I'm not talking about twinkies, I'm talking about orange juice. Because make no mistake about it, unless you cut and juice oranges yourself, the orange juice you drink is chemically processed. It has to be—fresh squeezed orange juice goes bad on a time scale of a couple of days even with refrigeration. (Apparently you can buy unpasteurized OJ, but it has a "use by" date about 2-3 days after the oranges are juiced at the processing plant. I don't recall seeing it for sale in Canada, which is about a 24-hr drive nonstop from the orange groves... Doesn't mean it isn't here, only that I haven't seen it.)
You may have seen a few articles lately about a nuisance of a chemical called carbon dioxide, namely, that it's the waste product of a number of very common chemical reactions and doesn't itself react with much (other than plants, but that reaction isn't fast or extensive enough to keep up with our current production rate) meaning it accumulates in the environment.
So, we're trying to make sure less of it gets into the environment. One class of methods which you may have heard of is carbon capture and sequestration, where after production it's captured, compressed, and often pumped deep underground—sometimes into retired oil wells, sometimes into the deep ocean, or many other places.
Before it can be stored, however, it has to be captured. Scrubbing can be highly effective at removing CO2 from smokestacks and other concentrated sources, traditionally with amine solutions. Then there was a new discovery about the CO2 absorption of polyethylenimine, which was what caused me to start researching this post.
One of the issues with a reaction that is very effective at grabbing a chemical out of the air is making it let go again. Most of the chemicals that are good at grabbing CO2 are too expensive to use only once. Polyethylenimine is of great interest because it releases the CO2 easily by heating it up, which can let the CO2 be collected in concentrated form for use elsewhere.
After discussing the options with one of my co-workers, I installed SciPy and all its associated dependencies, because it was free and had more than enough computational power to do what I wanted to play with. I don't know enough about any of the computer-math programs to make a case for work buying me one of the very expensive programs, and I couldn't rationalize buying such a program for myself at home to play with, so open source it is.
My first "project", such as it was, was both somewhat practical and relevant to my work, while still being easy enough for a first project: calculating how long it takes for the flow to reach steady state in a series of tanks with a pump at one end (step change input) and gravity flow all the way through.
For the ever-shrinking world of micro-electronics, I hear the size of the wires themselves are a tricky problem to handle. For one thing, how do you place and solder a wire that's only a dozen atoms across? I don't work in micro-electronics (or any kind of electronics) so that's all I'll say about that.
However, a new nanowire has recently been connected between two tiny electrodes. It's so tiny it can only be seen under an atomic force microscope, and this is what it (well, a whole series of them) looks like:
They conduct nearly as well as copper, and made extremely low-resistance contact with the electrode surfaces they're connecting. Even better? They're self-assembling with an easy to control "on" switch, and charging the electrodes before triggering the self-assembly means the wires build themselves between the charged electrodes and nowhere else.
My home bioreactor took 48 hours to get going where the instructions said 24-36 hours was typical, but it got going. About two weeks after startup the active cell culture had matured and I decided to put it into production. The instructions indicated that 1.5 hours at room temperature would be an adequate first stage reaction period. Four hours into it the first reaction stage wasn't finished, so I put the lot into the fridge and went to bed; clearly the time estimates were not representative.
I knew putting it in the fridge would slow the reaction down to the point where I could pick it up again the next day, because it's a bioreactor and they're sensitive to temperature - specifically, the reproduction rate of the cell culture slows down dramatically when cooled.
That's when I realized that my bioreactor had been reacting more slowly than the instructions suggested was normal every step of the way.
Generally speaking, a sudden drastic change in the chemistry of your environment is catastrophic. From bacteria to humans, there is a range of chemistry we can tolerate, and outside that range we tend to die.
I mentioned one major geochemical event last year, when free atmospheric oxygen first became common. That was a pretty catastrophic change for the living creatures (bacteria) who were adapted to the pre-oxygen conditions of the early earth.
Some time after that, another major geochemical event happened. Some researchers now think that this led directly to the cambrian explosion and to more complex life on earth. Even so, it was a catastrophic change—from the point of view of the creatures who didn't survive it.
I now have a home bioreactor.
This is what it looks like 48 hours after startup:
Of course, I only realized after the bugs started farting all that CO2 that I didn't actually have a microscope at home to see what they were doing and what was there. I may have to start a second bioreactor after finding myself a microscope capable of seeing who's at home in that jar, to see how the population changes over time.
Hmm, it looks like telescope stores often sell microscopes as well. Magnifying optics are magnifying optics, I guess!
Getting back into chemistry after last week's fun little diversion into mechanics, I feel like doing some more math. I was looking for a recipe not long ago and ran across repeated mentions that one adds salt to water when boiling food in order to raise the temperature at which the water boils, thus cooking the food faster.
Boiling point elevation is a real thing, as is freezing point depression, and it's not hard to calculate.
The boiling point of pure water at sea level is 100oC. In order to calculate the change in temperature, we need the following equation:\[\Delta T = K_b m\]
More fantastic robots! These ones are inspired by one of the creatures I find the most fascinating: snakes.
This little guy from Carnegie Mellon Biorobotics (still tethered to its power source and remote control) can move in all kinds of ways; as the video says, not just slithering. Quite a few of these types of movement are actually very simple repetitive motions, while others are much more complicated, with more steps in the movement.
It wasn't so long ago that photovoltaic solar panels were expensive, hard—and dirty!—to produce, inefficient sources of very expensive power.
In the last little while, however, a flurry of advances have improved on all of those problems. So many announcements have come out lately that I've delayed this post repeatedly due to the sheer quantity of new information. But that's not going to stop, so I'll post what I have now, and I may post again later.
For a super-quick summary of first-generation photovoltaic power, the panels were made of silicon using a process that involves toxic chemicals and high temperatures, were very fragile, expensive, and had a low efficiency and limited lifespan.
But now they're becoming cheap, tough, flexible, easy to make, and remarkably efficient and durable.
I am fascinated by crystals, particularly by their regularity. They basically consist of a unit cell that repeats over and over again, identically, across the whole span of the crystal. And if the crystal is big enough to see with the naked eye, that's a very large number of unit cells.
Very simple crystals, for example table salt (NaCl), have a tiny unit cell consisting of 4 atoms of Na and 4 atoms of Cl, arranged in alternating rows, a structure that is called face-centred cubic, because on each face of the cube, there's an atom in the centre of the same type as the atoms on the corners of the unit cell.
An interesting quirk of the simple 1:1 ratio cubic crystal structure is that you can define either Na or Cl as the corners of your unit cell, and it'll still be face-centred cubic.
Diamond's structure is also simple: every carbon atom has four links to four other carbon atoms, arranged in a tetrahedral shape around it. Because unit cells are defined as cubic or rectangular shapes, however, the diamond unit cell is less simple, even if the structure itself is simple.
I just discovered the "Symphony of Science" series of music videos. Gorgeous visuals in this one, both on the screen and inspired in my head by the lyrics.
I don't really have much to say about it, except that it makes me happy when I watch it. This music video has lyrics made entirely from recordings of things said by Carl Sagan (with a verse by Stephen Hawking), with their tone digitally altered to fit the melody.
Here's a little random bit of fun for today: kitchen games with surface tension.
One of the things that changing surface tension does is determine how stable bubbles are. So, let's change the surface tension of boiling water with some common household items.
If you set a pot of water on the stove to boil, the lid will rattle when it gets going, and that's about the extent of it. The bubbles pop quickly and aren't very stable.
If, on the other hand, you set a pot of water with some white rice in it on the stove to boil (and forget to turn it down to low the instant it starts to boil) it'll foam up and boil over and make a great big mess of your stove. If you're one of the other three people left in the world who both cooks rice and hasn't got a rice cooker, you've probably had this happen to you at least once.
A while ago I noticed something interesting: there are certain additives you can put in a pot of white rice that changes the surface tension yet again, so it goes back to not boiling over. My favourite of these additives is ground coriander seed, stirred in while the water is still cold. Also, it makes for some really tasty rice. Garlic powder also helps: while the water still foams, it doesn't grow as tall and boil over as quickly.
Water, despite the fact that it's incredibly common, is actually a pretty strange compound. Some of its stranger properties make it particularly useful for life, such as the way it switches from getting denser as it gets colder (normal) to getting less dense as it gets colder (not normal) below 4oC.
A recently discovered and even more recently characterized weirdness of water is that on the nano scale and on hydrophobic surfaces, water spontaneously flows in instead of being expelled the way one would expect based on the usual reaction of water to hydrophobic materials: (blue in the image below)
Some random stuff I've learned from my field work: some of this is really blindingly obvious in retrospect, but which I didn't learn in university and thus didn't think of until I ran into it, sometimes embarrassingly face first and sometimes by trying to use an existing bad design.
> Operations and maintenance don't like crawling on their hands and knees on gravel to get at equipment that needs maintenance.
I told you some of these would be blindingly obvious. I have seen limited access to not only equipment for maintenance, but also to valves that need to be used on a regular basis. I have also personally needed to work a valve several times per day where I had to thread my hand between several tubes just to reach it. Fortunately I have skinny hands, and none of the tubes were hot.
Since it was free, and it was about everyday science everywhere and teaching people about science, I downloaded it. Because, you know, Science!
I was nodding right from the first two paragraphs of the preface. Do you remember going to some museum, or aquarium, or other educational and fun location, get interested, have a fun time, then at the end of it get asked by your teachers or parents, "what did you learn?"
And then drawing a blank.
The funny thing is, the first thing I thought of when I read that was actually back in university, when halfway through any given class the professor would announce the date of the midterm: my first thought was usually to wonder what he could possibly test us on, we hadn't hardly learned anything.
I don't know if the book answers the question of how to help kids answer the question "what did you learn?" (I haven't finished reading it yet) but it certainly tries to answer the question of how to help people learn and absorb and integrate science more effectively.
Personally I think instead of asking what they learned, you should ask your kid what were some of the cool things they saw. They'll probably surprise you with the amount of stuff they learned. (I saw a deer with fangs at a museum once. That was seriously weird.)
What is shown on the right, sticking to the metallic disk being lowered into the liquid, is magnetic soap. (On the left is normal, non-magnetic soap.) The little yellow blob that lifted with the magnet-on-a-stick through the clear liquid and then fell when the magnet was lifted right out of the liquid, is the soap itself.
A solution of ferric chloride by itself also reacts very slightly to magnets, but it finds most of its use as a coagulant, not as a soap.
In keeping with my original plan for this blog, I am now going to teach myself something new.
Here is something I have known about and occasionally seen since I was a kid, and know the name of, but hadn't seen it in operation and didn't actually know how it worked until I decided to write this post and figure it out:
It works exactly the same way as this thing, which I saw for the first time as an adult:
It may be something we don't like to think about, but one of the things the astronauts have to do while in orbit will be coming more and more to Earth. Fresh water is limited, and getting more so with time. Water conservation helps, but it may not be enough in the future.
Whether they are dependent on well water or surface water, many cities have to worry about having enough water to last through the dry season as the water levels drop. Water restrictions are common in some areas; where I grew up, part of the summer routine was that you couldn't water your lawn whenever you wanted, but only on certain days. Sometimes there was an outright ban on watering lawns if the river level was too low.
As wastewater treatment technology improves, the sewage plant's discharge gets cleaner and cleaner, so why not use it as feed for our clean water treatment system?
An airplane made that hole.
Not by just flying through it and swirling the visible cloud out of the way, that makes a different pattern which doesn't last nearly as long.
It turns out that in certain conditions, airplanes can actually induce rain or snow in a localized region of a cloud, and the precipitation is what clears the hole - the water droplets that make up the cloud fall because of the airplane.
Well, I haven't been at this for a full year, but it's been an interesting seven months so far. I've definitely spent a lot more time keeping up with the science news by trying to post something every week. I'm also glad I didn't set out to try to post more than one a week!
I think I'll stick with the Monday post schedule, even if sometimes I have to post something light. I'm also going to try to do more chemistry type stuff; it surprised me how much time I spent outside of chemical engineering and related fields. I also want to do more posts calculating random things, because the ones I've done so far were a lot of fun for me.
Let's see how the next year goes...