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November 20, 2009

Make: Projects - Pneumatic trough, part II

image from golden book of chemistry experiments page 28.jpg

Last week I wrote about how to construct a simple sheet metal "bridge," which, in combination with an ice cube bucket and an olive jar, makes an effective pneumatic trough for collecting gas samples over water. This week I'm going to show you how to use this apparatus to generate and collect pure oxygen, and how to use that oxygen to observe the brilliant blue flame of sulfur oxidation.

Tools:

Pneumatic trough apparatus from part I
Small piece of plate glass (I used the mirror from a makeup compact)
Lighter
Twisted wire sample loop
250 mL Erlenmeyer flask (I got mine from The Maker Shed)
#7 two-hole rubber stopper to fit Erlenmeyer (mine came from this assortment)
Two 80 mm lengths of 5 mm glass tubing to fit stopper (such as this)
Approximately 18" length of 5/16" OD x 3/16" ID PVC tubing to fit glass tubing (common hardware store item)

Materials:

Water to fill bucket
Elemental sulfur powder (also called "Flowers of Sulfur," available at some drugstores and here.)
3% hydrogen peroxide (common drugstore item)
Manganese dioxide (can be recovered from an alkaline dry-cell battery or purchased here)
Petroleum jelly (drugstore)

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Posted by Sean Michael Ragan | Nov 20, 2009 12:30 PM
Chemistry, DIY Projects, Education, MAKE Projects, Science | Permalink | Email Entry | Suggest a Site

November 19, 2009

Make: Holiday Gift Guide 2009: Science and Chemistry

Those of you who know me will know I'm slightly biased toward chemistry, the discipline in which I'm trained, so it's hard for me to resist the natural temptation to focus on gifts that I might like for myself. So, if you astronomers, physicists, biologists, geologists, mathematicians, ecologists, computer scientists (and anybody else I may have accidentally left out) have suggestions for those in your own disciplines, please feel free to submit them in the comments! Chemists, too, of course!

Molar beach ball ($7.50 from the American Chemical Society)
A "mole," in case you don't know, is the unit used by chemists to enumerate atoms or molecules. One mole is Avogadro's number (6.02 x 10²³) of individual atoms or molecules. One of the remarkable things a person learns in general chemistry is the huge difference in molar volumes between liquid and gas phases. A mole of liquid water, for instance, takes up 18 mL, whereas the same number of water molecules in the gas phase takes up 22400 mL! Another interesting fact is that, because molecules interact so little with each other in the gas phase, all gases have effectively the same molar volume, which, again, is 22400 mL, or 22.4 L, at average atmospheric temperatures and pressures. The American Chemical Society has designed this cool beach ball to contain 22.4 L, or one mole, of gas. It's a great teaching aid and a nifty idea in general.

Borosilicate coffee cup ($9.99 from ThinkGeek)
Part of the experience of becoming a chemist is learning to appreciate glass. Glass is totally ubiquitous in our world, but only after working with it under the relatively extreme conditions of the lab does one really begin to appreciate how truly amazing its properties are. Worked with relative ease, resistant to almost all chemicals, capable of enduring extremes of temperature and pressure, and to top it all off, transparent so you can see what's going on, borosilicate glass is surely one of the greatest achievements of materials science. Besides these reasons, chemists and other scientists tend to run on coffee (I've even gone so far as to suggest that coffee causes scientific thinking, to some extent), and at ten bucks, you'd be hard pressed to find a more cost-effective gift for one than this borosilicate coffee mug from ThinkGeek.

Water aspirator ($19.90 from Science Kit)
Every hobby chemist wants a vacuum pump, but many of us can't afford one, either in terms of absolute cost or in terms of available space. Fortunately, there's a wonderful low-tech way to generate a low vacuum, suitable for filtration and many distillations, using an ordinary sink and this inexpensive bit of kit called an "aspirator." The aspirator exploits the Venturi effect (Wikipedia) to generate negative air pressure at the sidearm from the flow of water out the bottom. And while it may look like the sort of thing you could build yourself from hardware store bits and pieces, in point of fact the hydrodynamics of a good aspirator are fairly complicated and it makes much more sense to just buy one. You may have to buy an adapter to make it fit your particular sink, but these can almost always be found at the corner hardware store for a couple of extra bucks.

Theo Gray's Mad Science ($24.95 from The Maker Shed)
I reviewed Theo Gray's newest book for MAKE, Volume 19, and had this to say about it:

If you've ever thrilled to a chemistry demonstration, Mad Science will bring you great joy. If, like me, you've ever wiled away an evening (or eight) figuring out just how hard it would really be to construct your own 3 MeV linear accelerator for making Lichtenberg figures, you may be unable to put it down. My review copy is dog-eared at nearly half of the fifty chemical wonders included: Investigate this. Build that. Would it be possible to...?. In the week since I got it, I've already been to the shop more than once to fan some spark that struck while leafing through its pages.

The book has beautiful photos of those experiments that are too dangerous for most of us to try on our own, and plenty of safer fare for those who want to play along at home.

illustrated guide to home chemistry experiments.jpg

Robert Bruce Thompson's Illustrated Guide to Home Chemistry Experiments ($29.99 from The Maker Shed)
Illustrated Guide to Home Chemistry Experiments is absolutely the best guide to hobby chemistry that I have ever encountered. In 22 chapters across 413 pages, Bob takes his readers through the basics of keeping a notebook and safely storing chemicals to the subtleties of organic synthesis and forensic analysis, and all with a ferociously independent, hands on, less-is-more DIY style. I really love this book.

1000 mL separatory funnel ($39.95 from The Science Company)
The dedicated amateur or hobby chemist can achieve amazing things using old jelly jars and coffee pots, but there are several pieces of "professional" laboratory glass that are difficult to improvise from common materials, and the most useful of these is probably the separatory funnel. A good sep funnel, with a teflon stopcock and a ground-glass joint and stopper, is essential to perform the liquid-liquid extractions that are a routine part of even the most basic isolations and syntheses. And you can almost never have too many. This 1000 mL version from The Science Company is large enough for nearly any purpose. A ring stand and 4" support ring to hold it in place makes a nice afterthought.

Distilling apparatus ($49.95 from The Maker Shed)
The Maker Shed offers this really beautiful borosilicate glass distillation kit, including a 1000 mL sidearm flask with stopper and a 200 mm spiral "Graham" condenser, all at the truly astounding price of $49.95. All the joints are easily demountable gas/liquid-tight ground glass, so there's no monkeying around with rubber stoppers or bits of glass or rubber tubing to make the connections. Distillation is used for separating mixtures of liquids having different boiling points, and the most common use, of course, is in making liquors like whiskey or brandy from beer, wine, or mash. Again, you might want to throw in a couple of ring stands and utility clamps.

Electronic tabletop balance ($117.00 from The Maker Shed)
A good balance is a totally indispensable tool for quantitative chemistry of almost any type. The important figures of merit for a balance, in rough order from most to least vital, are resolution (the number of zeroes after the decimal point), capacity (the maximum upper mass limit), precision (the consistency of repeated measurements of the same mass), accuracy (how close it reads to the "true" value, which is easily corrected by calibration), and linearity (how well precision and accuracy are maintained across the balance's mass capacity). The better each of these figures, the more the balance will cost. Professional "analytical" balances, capable of weighing to a milligram (0.001 g) or less, cost thousands of dollars and include an enclosed glass cabinet over the weighing pan to prevent interference from air currents, which they are sensitive enough to detect. Hobby chemists generally have to compromise, but good centigram (0.01 g) balances are quite accessible and are adequate for most purposes. This My-Weigh iBalance 201 digital balance from The Maker Shed has centigram resolution and a capacity of 200 g, and was recommended to us by Robert Bruce Thompson, author of our Illustrated Guide to Home Chemistry Experiments.

Laboratory hotplate / stirrer ($149.95 from The Maker Shed)
After using a stirring hotplate for awhile, you'll start to get annoyed that your kitchen stove doesn't include a magnetic stirrer. And for $150 new, you'd be hard-pressed to beat this combination unit from The Maker Shed, which includes a built-in ring stand support, rod, and thermometer clamp. Don't forget a couple of teflon stir bars to actually do the stirring.

For many more chemistry and science-related gift ideas, check out the Science Room in the Maker Shed.

The Maker Shed has all sorts of other great holiday gift ideas, Arduino & Arduino accessories, electronic kits, science kits, smart stuff for kids, back issues of MAKE & CRAFT, box sets, books, robots, kits from Japan and more.

Holiday Shipping Deadlines in December:

04 (Fri) - Deadline for microscope shipping
11 (Fri) - postal shipping deadline
14 (Mon) - ground shipping deadline
18 (Fri) - FedEx 3-day shipping deadline
21 (Mon) - FedEx 2-day shipping deadline
22 (Tue) - FedEx overnight shipping deadline

*Customers experiences on orders with these ship methods placed after these dates may vary, the dates listed are what we call "safe dates"

USPS (Any Method):
Due to the high volume of mail that the postal service deals with around the holidays, order by Dec. 10th, however, many packages are lost or delayed in transit and we do not replace or refund any orders lost using this ship method, we strongly encourage you to not use this method in December.

Visualizing sound with fire

Wow, rad physics experiment in which FIRE is used to visualize sound. Don't try it at home, unless you're a physics teacher, in which case please show this to your students. [Thanks, Tyler!]

Sundial cannon fires at noon

The glass is aligned to concentrate the sun's rays, lighting the cannon's fuse at high noon. More pics here, and a very detailed .pdf from the British Sundial Society on so-called "noon cannons" here. [via Neatorama]

November 18, 2009

"Bomb-proof" kevlar wallpaper

Very clever idea commercialized as the X-flex Blast Protection System, in which a high-tensile-strength composite film is applied to the inside of a masonry wall to reinforce it against lateral impact. The video embedded above was produced by Popular Science, who included the X-flex system in their Best of What's New 2009.

November 17, 2009

Make an LVDT with soda straws

It's the McLVDT, a linear variable differential transfomer, made from McDonald's straws. The creator writes:

I made a primary coil on a normal sized straw, and made two secondary coils on the outside of the larger McDonald's straw. Since the McStraw is large-bore (perfect for those thick high calorie shakes), the smaller straw with the primary winding fits nicely inside. The position of the inner straw can be determined by examining the amplitude and phase of the combined signals of the secondary coils, which is shown in raw form on the oscilloscope.

"Mc"LVDT

November 16, 2009

The Bloop of Cthulhu?

This may be one of those situations where my love of a good story gets me in trouble with the more hard-minded scientific types among you, so please understand first that this is all intended in fun. Nonetheless, there are some intriguing facts here.

During the summer of 1997, the U.S. National Oceanic and Atmospheric Administration (NOAA) repeatedly detected an extremely powerful underwater sound on an array of Cold War era hydrophones originally installed to listen for soviet submarines. "While it bears the varying frequency hallmark of marine animals, it is far more powerful than the calls made by any creature known on Earth." Phil Lobel, a marine biologist at Boston University, purportedly "agrees that the sound is most likely to be biological in origin," although his opinion appears to be in the minority. (Both quotes from this article at CNN.com.) The approximate origin of the sound has been identified as 50 S x 100 W, which is almost exactly the same latitude as Lovecraft's fictitious sunken city of R'lyeh, at 48 S x 123 W, although it is 1000 miles distant in terms of longitude. [Thanks, Maredith!]

You can listen to a sped-up version of "The Bloop" on the NOAA website here.

November 15, 2009

History of curved origami

Interesting article from MacArthur fellow Erik Demaine covering the history of origami-style models that include curved folds. Shown above is "Concentric Circular Tower" by late UCSC Professor and noted computer scientist David A. Huffman (Wikipedia), whose curved-origami work was covered posthumously by the New York Times in 2004. The Flickr curved fold pool is chock-a-block with fascinating models of this type. [Thanks, Jon!]

More: Curved tetrahedron origami

November 13, 2009

Make: Projects - Pneumatic trough, part I

Although it sounds like some kind of euphemism from Brave New World, a "pneumatic trough" is actually a very handy piece of classic chemistry lab kit. Besides providing a convenient means to collect samples of pure gases for various experiments, a pneumatic trough with a graduated container allows the easy volumetric measurement of reaction yields for gas-producing reactions.

If that all sounds too complicated, don't sweat. What I'm going to show in this tutorial is simply how to build a simple piece of apparatus that allows you to collect pure gas samples over water. You can collect carbon dioxide, oxygen, hydrogen--almost any gas you can generate and direct down a hose.

It seems like a simple enough bit of equipment: all you need is an upside down container suspended in a bucket of water. Finding a convenient way to set that up, however, is tougher than it sounds. The pneumatic trough presented here, which uses a sheet metal "bridge" to secure the glass column, is by far the most painless and economical way to make it work that I have found. The basic idea is derived from illustrations in Robert Brent's 1960 Golden Book of Chemistry Experiments (from which the title diagram is taken), but the addition of an aperture shaped to accept the threads of a glass jar is of my own devising.

Read full story

November 12, 2009

Sensing chemicals? There's an app for that.

If you don't have any bomb-sniffing bees around to look for trance quantities of explosive gas, why not use your iPhone instead? That's exactly what Jing Li and a team of researchers from NASA have done with their cell phone chemical sensor. By interfacing a postage stamp-sized sensor to a popular smart phone, they were able to create a device that can sense airborne ammonia, chlorine gas and methane, and report its findings over the cellular network or WiFi. Admittedly, it took a bit more than just a bit of software to add an electronic nose to the iPhone, but it's still pretty neat use of a consumer device. [via inhabitat]

Be a counselor at Space Camp

In high school and college, I was a camp counselor almost every summer, and I highly recommend it! It's such a rewarding experience and you make so many lifelong friends. So when I found out (from CRAFT's Rachel Hobson) that they're looking for counselors for Space Camp, I had to share. So many makers would make fantastic counselors!

The Space Camp mission is to use the excitement of the U.S. space program to stimulate young people's interests in the study of math, science, technology, and aviation. These immersive programs place students in a real world context allowing them to view math and science as something more than just an academic exercise- allowing them to recognize these subjects as tools to develop future careers as scientists, engineers, teachers, astronauts, and pilots. By combining cutting edge technology with hands on learning our counselors inspire young men and women to dream big and to work hard to make those dreams a reality.

Temperature regulating coffee mug

Klaus Sedlbauer and Herbert Sinnesbichler, of Germany's Fraunhofer Institute for Building Physics (IBP), think coffee is perfect at 58 degrees C. So they built a coffee mug that automatically maintains that temperature, tending to cool its contents above 58 degrees, and releasing heat below 58 degrees to warm them back up. It works by use of an interstitial phase change material (PCM, Wikipedia) between the aluminum fins, which has a solid-liquid phase change temperature of 58 degrees. Above 58 degrees, the PCM melts and absorbs heat, and below 58 degrees it freezes and releases heat. Supposedly it can keep a cup of coffee at ideal temperature for 20 to 30 minutes.

November 11, 2009

Company offering free SEM samples

Wondering what something you own would look like under a scanning electron microscope, but don't happen to have one in your garage? Well, then you might be interested in this intriguing offer from ASPEX: a complimentary SEM scan of your favorite object!

This looks like a really awesome service, however I am a bit suspicious- their sample photos are all high quality stock images, and there doesn't seem to be a way to specify the orientation of the scan. Anyone want to try it out? Be sure to let us know your results!

[Thanks, Matt!]

November 10, 2009

Layer-additive "welding" 3D fabrication

Electron Beam Free-Form Fabrication (EBF3) is a rapid prototyping technology developed by Karen Taminger of NASA's Langley Research Center. Dr. Taminger is prone to market EBF3 by analogy to Star Trek style "replicator" technology, which is nothing but shameless hype. Still, the basic idea is an interesting twist on extrusion-based 3D printing technologies (although there's not really any "extrusion" going on), and is under development with an eye towards space-based fabrication. Working in outer space would eliminate the system's major ground-based shortcoming, which is the requirement for maintaining a vacuum or inert atmosphere to prevent oxidation of the weld.

"Know It All No 2 Pencil Set"

Il 430Xn.97864336
"Know It All No 2 Pencil Set" on Etsy, lovely.

November 9, 2009

'Teeny Ted' is worlds smallest book?

Reaching for your glasses won't help you read this book. Teeny Ted from Turnip Town, written by Robert Chaplin, is written on tablets only 11x15 microns (1/1000 of a millimeter) wide. That means that you will need an electron microscope to read it. Though it was created back in 2007, this is the first I have heard of it.

To make the book, a focused ion beam machine was used to carve the pages into tablets of single-crystal silicon. It's a pretty impressive feat to print an entire book in less than 7000 square microns, however I wonder how much physical space it would take to store it in digital form on a modern flash drive. Anyone know the calculation? [via international exhibition of calligraphy]

Guess the science photo...

Telegraph Multimedia Archive 01518 Flatulence 1518034I
Here's an interesting image from a science photo stock art site, know what's going on here? Click through to see if you're right...

Compact cellphone microscope

This novel approach to cellphone microscopy from Dr. Aydogan Ozcan from the University of California, Los Angeles, foregoes bulky lenses and magnifies electronically.

For this electronic system of magnification, inexpensive light-emitting diodes added to the basic cellphone shine their light on a sample slide placed over the phone's camera chip. Some of the light waves hit the cells suspended in the sample, scattering off the cells and interfering with the other light waves.

Far From a Lab? Turn a Cellphone Into a Microscope [via picturephoning]

More:
Cameraphone microscope extension revisited
Cell phone camera turned remote microscope

November 6, 2009

Martian landscapes

Universal Site Graphics Blogs Bigpicture Mars 11 06 M04 43790925

Universal Site Graphics Blogs Bigpicture Mars 11 06 M11 02211420

Martian landscapes - The Big Picture @ Boston.com via Waxy.

Since 2006, NASA's Mars Reconnaissance Orbiter (MRO) has been orbiting Mars, currently circling approximately 300 km (187 mi) above the Martian surface. On board the MRO is HiRISE, the High Resolution Imaging Science Experiment camera, which has been photographing the planet for several years now at resolutions as fine as mere inches per pixel. Collected here is a group of images from HiRISE over the past few years, in either false color or grayscale, showing intricate details of landscapes both familiar and alien, from the surface of our neighboring planet, Mars. I invite you to take your time looking through these, imagining the settings - very cold, dry and distant, yet real. (35 photos total)

November 5, 2009

"Large Hadron Collider scuttled by birdy baguette-bomber"

Cern Lhc T2030Shigh
The God machine just can't catch a break...

A bird dropping a piece of bread onto outdoor machinery has been blamed for a technical fault at the Large Hadron Collider (LHC) this week which saw significant overheating in sections of the mighty particle-punisher's subterranean 27-km supercooled magnetic doughnut.

According to scientists at the project, had the LHC been operational - it is scheduled to recommence beaming later this month - the snag would have caused it to fail safe and shut down automatically. This would put the mighty machine out of action for a few days while it was restarted, but there would be no repeat of the catastrophic damage suffered last September. On that occasion, an electrical connection in the circuit itself failed violently, causing a massive liquid-helium leak and knock-on damage along hundreds of metres of magnets.

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