Week of 24 May 2010
Update: Friday, 28 May 2010 08:26 -0400
- I got in a little lab time over the weekend. I was able to shoot another video for my YouTube channel, this one on making thin-layer chromatography (TLC) plates.
first used TLC back in the 60's. Commercial TLC plates were just
becoming available then, but they were much too expensive for my
budget. So I did what just about everyone else did at the time: I made
my own. That seems to be almost a lost art nowadays, at least among
home scientists. That's a real shame, because the cost of TLC plates--a
buck or two each for plates the size of a microscope slide, and you
have to buy them 50 or 100 at a time--means that very few home
scientists use TLC.
The small plates I show in the video are
useful for analysis. You spot the analyte on the plate and then allow
the mobile phase (solvent) to crawl up the plate, dragging the various
components of the analyte with it. Because the different compounds have
different affinity for the mobile phase versus the stationary phase,
they gradually separate as the mobile phase makes it way up the plate,
producing lines at various distances from the original spot. By
measuring the relative distances that each of the components moves, you
can identify the components. Colored compounds can be visualized
directly. Colorless compounds can be visualized by various techniques,
including UV light and various agents that react with analyte
components to produce colored compounds.
Larger plates with
thicker coatings are used for preparative chromatography. Once the
plate is developed, the portion of the plate coating that contains a
particular component can be scraped off the plate and the compound
extracted from the inert alumina powder. This is an extremely powerful
tool, and one that more home scientists should familiarize themselves
Well, perhaps my video will do some good. I've already
gotten a nice comment on it from a public high-school teacher in Ohio,
who said, "I'm working on my supply orders for school next year and you
just saved me a lot of money. Thanks for the great information."
Speaking of home science, Craig Venter and his team opened Pandora's Box last Thursday when they announced they'd created a synthetic life form.
Just to be clear, they did not create a living organism from scratch.
What they did do--and it will rightly earn them the Nobel Prize--was
create an entirely synthetic genome from the small building blocks that
make up the DNA of all living things. They then implanted that genome
in an existing cell to create a new type of life form. That cell
remained viable and capable of reproducing itself.
now, every living cell that exists on this planet had descended in
an unbroken chain from the earliest and most primitive single-cell
organisms that arose unimaginably long ago. Dr. Venter and his team
broke that chain. They are the only parents of this new life form.
what does this have to do with home science? After all, Venter and his
team spent 15 years and millions upon millions of dollars accomplishing
this feat. But one lesson we've learned is that what is cutting edge
science today will be within the realm of home science in a decade. By
2020, if not earlier, home science hobbyists will be creating their own
new life forms. Count on it. Some people will object, thinking that the
necessary tools will remain out of reach of home scientists. Dream on.
Ten years ago, the computer system I'm using to write this post would
have been a literal supercomputer. Ten years from now, you'll be able
to pick up the equivalent of one of today's supercomputers at Best Buy
for $500. And all the other stuff someone needs to create his own life
form will be equally available and cheap. There's no going back.
Pandora's Box is open.
That scares a lot of people. No doubt
most of them are now trying to figure out how to slam the lid on the
Box. That's not going to happen. The obvious fear is that hobbyists
will accidentally create and release a dangerous life form, or that
terrorists will do so intentionally. My gut reaction is that neither is
likely, but both are possible.
If it happens, a virus is the
likely culprit, mainly because viruses have small genomes that will be
easier to manipulate than those of higher organisms. And the thought is
certainly frightening. For example, the reasons that ebola virus is
largely contained are that it has a short latency and an extremely high
burn rate. In other words, people infected with ebola quickly become
obviously ill and die before they have a chance to infect many other
people. But what about a new artificial virus based on ebola, but with
a long latency? One carrier could spread that virus widely, with an
exponential and worldwide growth in infections before any symptoms
But virulent, lethal microorganisms are only a
tiny, tiny fraction of all microorganisms, and the likelihood of any
hobbyist accidentally creating a super-bug based on one of this is
vanishingly small. Terrorists might try, of course, but if we've
learned one thing about terrorists it's that they're stupifyingly
inept. Their brains are filled with radical religious nonsense, which
doesn't leave much room for scientific thought. If they attempt such a
feat, they're much more likely to do themselves in than harm any of us.
to slam the lid on Pandora's Box is not just futile, but
counterproductive. Instead, we should be making sure that lid is wide
open. We should be encouraging the proliferation of the science. Ten
years from now, we want to have lots and lots of people who are trained
and skilled in the technologies involved. The best defense is a good
And the other benefits will be extraordinary. For
example, just imagine a synthetic bacterium that eats sawdust, grass
clippings, and other cellulose waste and excretes a mixture of butanol,
ethanol, and acetone. (Of course, it would have to be engineered to die
quickly in the wild; otherwise, it'd eat the 2X4s in our homes...) As
the science advances, creating such special-purpose bacteria will
become trivially easy, and we can tell the Islamics to screw off and
drink their petroleum.
But we need to start now. We need our
best and brightest pursuing careers in science. We need lots more
biologists and biochemists and physicists, because it's that
intellectual capital that'll keep us on top. And, believe me, on top is
where we want to be in this new world.
Today is a regular day in the sense that Barbara is going to work,
followed by the gym, and then coming home at the usual time.
Unfortunately, we won't have many regular days this week. Barbara
cousin is in town for a visit, so she was away Sunday and yesterday
until late evening. Sadly, one of her few remaining uncles has just
died, so she'll be away for the funeral tomorrow. And for Thursday
evening she'd already made arrangements to have dinner with two of her
friends, before all of this other stuff happened. So it's Malcolm
and me mostly on our own this week.
From Malcolm's point of
view, I'm a very poor substitute for Barbara being here. Yesterday, I
ran a few errands. When I returned and Malcolm heard the garage door go
up, he started his usual insane barking to greet Barbara's return. When
I opened the door into the house, he was sitting there awaiting
Barbara. When he saw who it was, he said, "Oh, it's just you", and
turned around and went up the stairs and back to our bedroom to stretch
out on the bed and wait for Barbara. I understand that Border Collies
are one-person dogs, but I do wish he wouldn't be quite as clear about
One of the valuable lessons of science is that intuition is unreliable.
Mary Chervenak touched on this in the video about making copper ore,
and I've just encountered the same example over the last few days.
Sunday, I started making up 500 mL of a 1.0 molar copper(II)
sulfate solution. The molar mass of copper(II) sulfate pentahydrate is
249.68 g/mol, which means I needed 124.84 g for my 500 mL of solution.
But the copper(II) sulfate I'm using is only 99% pure, so I actually
weighed out (124.84/0.99) = 126.10 g. I transferred that to a labeled
storage bottle and added water to bring it up to about 475 mL. (I'll
make it up to 500.0 mL in a volumetric flask once the salt dissolves
So, here it is Wednesday morning, and I'm still
not finished making up that solution. Copper(II) sulfate is very
soluble in water, about 320 g/L at room temperature. But "very soluble"
doesn't translate to "quickly soluble" by any means. I allowed the
solution to sit overnight. When I checked it Monday morning, at least
half the copper(II) sulfate was still in crystal form at the bottom of
the bottle. So I brought it up to my office to baby-sit it. Every hour
or so, I'd invert the bottle several times. As of this morning,
probably 10 or 15 grams of the salt remains undissolved. This after
Here's where the unreliability of intuition comes in.
Most people would assume that a compound that is very soluble in water
would dissolve quickly, and the converse. Neither assumption is true.
Many heavy-metal salts, for example, are only slightly soluble in
water, but dissolve very quickly. So, two things that intuitively
appear to be closely related, solubility and dissolution rate, are in
fact unrelated. Solubility, the amount of a compound that will dissolve in a specific volume of solvent, is a thermodynamic property. Dissolution rate, the speed at which a compound dissolves, is a kinetic property.
Still waiting. When I inverted my copper(II) sulfate solution this
morning, there were still a few crystals present, maybe 5 grams or so.
On the other hand, I made up 500 mL of 0.1 M potassium iodide
yesterday. Potassium iodide is both extremely soluble--at room
temperature, about 1.4 grams of KI dissolves in 1 gram of water--and
has a high dissolution rate. When I weighed out the crystals and
transferred them to a bottle with a couple hundred milliliters of water
in it, the crystals actually dissolved before they reached the bottom
of the bottle.
Incidentally, the copper(II) sulfate solution is
an interesting example of purification by solution. The copper(II)
sulfate I'm using is sold in hardware stores as Root Kill, and lists an
assay on the bottle of 99% copper(II) sulfate. Nearly all of that 1% in
impurities is in the form of insoluble copper(II) oxide, which will
settle out on the bottom of the bottle as a fine black sludge. I'll
weigh a piece of filter paper, use it to filter the solution, dry
the paper, and weigh it. My guess is that the mass gain of the filter
paper will be very close to the extra 1.26 gram, leaving me with
essentially 100% pure copper(II) sulfate in solution.
cranking away on the extreme system chapter. We'll be starting builds
soon. The only missing components are the cases and power supplies,
which should be on their way to us shortly.
has announced its preemptive attempt to avoid government regulation by
implementing improved privacy controls. The problem is, none of the
changes actually do much to improve privacy. That was expected, because
the interests of Facebook and its users are diametrically opposed.
Users want their privacy maintained. Facebook wants its users to have
no privacy, because that's how it makes money. If Facebook were serious
about improving user privacy, it would make privacy the default.
Instead, it still makes sharing the default.
still the old opt-in versus opt-out problem. If Facebook really wanted
to do what was in its users' interests, it would make privacy settings
very tight by default, and allow those who wanted to share to opt-in.
Instead, it does the converse. I consider Facebook to be in the same
sleaziness class as spammers, and I sincerely hope it's headed for a
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