Yup, it’s time for those “top 10” lists for 2008.  I don’t generally post other peoples’ lists here, but heck, this is one area where I know that I haven’t been paying close enough attention to know what’s important.  So here is an edited version of the Physics Findings for 2008 from Physics News.  Phil Schewe does such a great job with these, they’re a delight to read.  You can read the whole thing at Physics News Update (and subscribe to their e-newsletter).

TOP TEN PHYSICS STORIES OF THE YEAR

The following list was chosen by editors and science
writers at the American Institute of Physics and the American Physical
Society.  It winnows a wealth of discoveries into the following ten
topic areas, which are listed in no particular order.

SUPERCONDUCTORS

What’s new-discovery of an unusual class of materials made from iron
and arsenic.   Superconductors don’t lose any energy when electricity
runs through them, providing they’re chilled to very low temperatures.
Superconductors are used in specialty applications where high
electrical currents are needed, such as in MRI scanners at hospitals or
in the magnets used to steer particles at atom smashers.  …

The new iron-arsenic materials are the first relatively
high-temperature materials that remain superconducting above a
temperature of 50 K that don’t contain copper; the copper materials are
brittle.  Researchers hope that the iron-arsenic version might lead to
the more practical manufacture of superconducting wire.   Furthermore,
having a new class of materials to study should help theorists
understand how high-temperature superconductors work in the first
place.
Background: A summary of work in this area can be found at Physics
Today, May 2008
; APS survey of topic.

LARGE HADRON COLLIDER

large_hadron_collider1

What’s new—the LHC, the world’s largest scientific instrument,
started operations in September.  At this huge particle accelerator,
located underground near Geneva, Switzerland, two beams of protons, each
traveling at unprecedented speeds will be smashed together.  The goal is
to create exotic new particles that can’t be observed in any other way
except in the tiny fireball created by such violent collisions.  ….

Problems with some of the apparatus forced a premature shutdown
…  General operations should resume in summer 2009.
Background: a summary of the magnet malfunction which brought testing to
a halt in September and a timetable for operations are available here.

PLANETS

What’s new-planets orbiting distant stars have been imaged directly, and a host of interesting results have come back from spacecraft hovering near the planets in our own solar system.  Extrasolar planets, planets orbiting far-away stars, had been detected indirectly by watching what happens to the light coming from the star.  But now the glare of the star has been blocked sufficiently that the extrasolar planet itself could be imaged.  The Gemini, Keck, and Hubble telescopes provided pictures. Background summary here.

In our own solar system, at Mercury, the Messenger spacecraft  made  first-ever maps of large portions of the surface. At Saturn, the Cassini  craft found geysers near the south end of the moon Enceladus.    At Mars, measurements made by several craft strengthened evidence in favor of sub-surface glaciers outside the polar regions. Meanwhile, the Venus Express craft recorded pictures at several wavelengths, facilitating, among other things, a better knowledge of clouds on Venus.

QUARKS

What’s new-unusual combinations of quarks were observed for the first time.  Physicists believe that an atom consists of one or more electrons orbiting a central nucleus.  The nucleus, in turn, is made of protons and neutrons, and these particles are made of something still more elementary-quarks held together by gluons.  … One discovery consists of the sighting of nuclear particles containing rare “bottom” quarks.  Background here.

[See the full article at Physics News Update for more on these experiments   -geekgirl]

FARTHEST SEEABLE THING

What’s new-seeing a flash of light from 7 billion light years away.
One of the brightest of all celestial objects is gamma-ray bursters,
objects that emit immense amounts of gamma radiation, the highest-energy
form of light.  The brightest-ever gamma ray burster was observed by the
Swift satellite.   Since looking out into space is equivalent
to looking back in time, this flash would have been coming from a moment
when the universe was only half its present age.  Publication in Nature.

ULTRACOLD MOLECULES

What’s new-first ever accumulation of molecules in large numbers and
at a temperature near absolute zero.  Using lasers to slow a gas of
particles down to near stillness is by now a standard method for
measuring the subtle properties of atoms.  Steven Chu, nominated to be
the Secretary of Energy, won a Nobel Prize for pioneering this subject.
Cooling molecules in this same way is difficult since molecules, made of
two or more atoms, have complicated internal motions.  But this year
several labs succeeded in first cooling atoms and then, at a temperature
close to absolute zero, getting them to combine into molecules. …
Background at http://www.aip.org/pnu/2008/split/875-1.html; figure
http://www.aip.org/png/2008/306.htm; PRL text and overview at
http://physics.aps.org/articles/v1/24

DIAMOND DETECTORSdiamond

What’s new-getting little imperfections in diamond to tell us about
how atoms behave like tiny magnets.  Diamond is made of a cross-linking of carbon atoms.  If one
carbon atom is missing from this network, the empty hole, in combination
with a stray nitrogen atom, acts as a sort of strange molecule in the
middle of all those carbon atoms.  This “molecule” can light up like a
little LED when you shine laser light in.  This in turn, can be used to
measure extremely weak magnetism.  Possible applications include data
storage for computers or high-sensitivity detectors. … See news summary at
http://www.aip.org/pnu/2008/split/858-1.html.

COSMIC RAYS

What’s new-experiments settle one mystery and uncover others.  Cosmic
rays are super-high-energy particles whizzing through the cosmos.  When
they smash into our atmosphere the rays turn out mostly to be ordinary
particles, such as protons or electrons, but with energies thousands or
millions of times higher than particles speeded up at accelerators on
Earth. [See full Physics News Update article for new results — there are many!  -geekgirl]

LIGHT PASSES THROUGH OPAQUE MATTER

What’s new—getting light to behave in a new way. When light strikes
an opaque material like milk most of the radiation is scattered; little
of it passes through the sample.  But in an experiment at the University
of Twente in the Netherlands, much more of the light can be made to
traverse the scattering material if beforehand the wavefront of the
incoming light is shaped by special filters. Background summary.

MACROSCOPIC FEEDBACK COOLING

What’s new—Scientists at the AURIGA lab in Padova, Italy have cooled
a one-ton aluminum bar to a temperature below 1 milli-kelvin using
special electrical circuits.  The bar is part of a detector designed to
measure passing gravity waves from space.  Using sensitive magnetic
sensors and feedback coils, the ringing of the bar (which is essentially
a large tuning fork) at one characteristic frequency was cooled from an
equivalent temperature of 4 K (the temperature of the bath of liquid
helium in which the bar sits) to a temperature of about 0.17 mK.  Lower
temperatures than this have been achieved with this feedback cooling
technique but only with much smaller masses.  Background: essay and PRL
article at http://physics.aps.org/articles/v1/3

Phillip F. Schewe

tt_icon_170This week’s episode of my Science Teaching Tips podcast actually features, well, me! Yay. It’s nice to record myself, not always other people, though the folks at the Exploratorium are so darned clever and fun, I feel it’s my mission to document every last scrap of their wisdom and energy. I’m trying…

So, this time I give you a way to adapt a great Exploratorium exhibit to something you can do at home with a friend and a set of keys.  It’s about how we localize sound, which is something very important for people who use sound to navigate (like blind people).  So, find out more about the perception of sound by listening in to this week’s episode.  For those of you who haven’t listened before, these are just 5 minutes long!

Listen to Find that Sound.

Wow, I was just sent this information about a wonderful chance for teachers and students to connect (for FREE) with a really dynamic scientist, Michio Kaku.  You can see my previous post about a talk he gave on the Physics of the Impossible at AAPT last summer — he was an incredibly gifted speaker. Funny, interesting, and really tuned in to what teachers can use.

It’s next Wednesday, December 17, 2008 12:00 pm EST and hosted by Discovery Education.

Register for the event here.

Michio Kaku is a best selling author, host of two national weekly science radio programs, and frequent guest on television shows including Larry King, 60 Minutes, 20/20 and many more. He has hosted numerous programs for the Science Channel and is currently increasing people’s Science IQ every Sunday night in the series “SciQ”. If you’ve ever seen Michio speak before, you know that he has a brilliant ability to break down incredibly complex theories and explain them in ways that anybody can understand. On on December 17th, he’ll be sharing his ideas directly with you and your students! This is your chance to connect your students to one of the most dynamic scientists on the planet, and even have him address their questions directly!

Michio Kaku’s website

scotchYeah, yeah, I know, this is old news, but I finally got around to reading the articles about the fact that Scotch tape emits x-rays. I’ve known for a while that when you stick scotch tape to something and then peel it off, the scotch tape gets charged (negatively for those who care). This is a great way to make a cheap electroscope for your classroom (or just anytime you want to find out the charge on something). Just stick Scotch tape to a table, peel it off, and then hold it near some Charged Object. If the tape is repelled, then the Charged Object is negatively charged (since like charges repel). Try it, it’s cool.

So, anyway, when you peel the tape off the table, it gets negatively charged by ripping electrons off the table. This is, in effect, a current — electrons are flowing from the table to the tape. If you peel tape off a table in a dark room you’ll see light. From what I gather, as the electrons slow down when they hit the tape, they give off radiation (this would be Bremsstrahlung or “Braking” radiation). When you do this in a dark room, you’re seeing that radiation as visible light.

The new research shows that if you do it in a vacuum, instead of these visible photons (which are just a form of electromagnetic radiation with a relatively low energy), you get x-rays (electromagnetic radiation with high energy). The x-rays were strong enough to take a picture of one of the researchers’ finger.

The NY Times article on this says:

All of the experiments were conducted with Scotch tape, manufactured by 3M. The details of what is occurring on the molecular scale are not known, the scientists said, in part because the Scotch adhesive remains a trade secret.

Other brands of clear adhesive tapes also gave off X-rays, but with a different spectrum of energies. Duct tape did not produce any X-rays, Dr. Putterman said. Masking tape has not been tested.

I’ve got so many different posts that I want to write… scribbled notes on different science myths and beautiful everyday things, but I have been so very busy. I’m sorry. I will get back to writing detailed posts in a few weeks!

In the meantime, I’d like to recycle a good old post on making your own phonograph. If you’ve got some old records, try this one, it’s pretty astounding when it works!

—–

phonographI love this little activity… Have an old record but no record player? Here’s how you can listen to it. Take a record and stick a pencil through the hole in the middle so it’s pretty close to the point of the pencil. That’s your turntable. Now take a piece of paper and roll it up into a loose cone and tape it. Flatten the pointy end a little and stick a pin through it. You may want to tape the pin to the end of the paper cone so it’s more stable. Now have a friend turn the record by slowly rotating the pencil. Place the pin, point down, on the groove of the record, and gently hold the cone so the pin stays in the groove of the record. Try to turn it at 33 1/3 times per minute — good luck! Here is a more detailed description of the activity.

Here is my post on my podcast where you can hear how it sounds and how to teach it.

You should hear the music playing, albeit a bit wobbly. The record has a groove in it — one long spiral. The needle vibrates in response to the shape of the groove. But the needle on its own doesn’t vibrate very much air. When it’s attached to the cone, it vibrates the cone, which can then vibrate more air, making the sound louder. The cone also directs the sound, making it easier to hear.

Today’s students often haven’t seen a record before, and so it can be useful to look at it under a microscope or magnifying glass to see the groove. Note that a CD is also sort of “carved” — it has microscopic pits in it. But instead of mechanical vibrations, the grooves in the CD are so tiny that it interacts with light. That’s why records wear out — the needle wears out the grooves. That’s not a problem with CD’s, since it’s just light touching the surface. Interestingly, it doesn’t matter (as much) if you scratch the side of the CD with the rainbows on it — but if you scratch the metal coating on the other side, the light won’t reflect from it correctly and you’ll spoil the CD.

Wikipedia has more information on phonographs, and so does this site from Arbor Scientific.

If you’re interested in making your own working phonograph (not just the pin and paper method) to actually record your voice using a plastic cup (replacing the old fashioned wax cylinder), check out this kit from Make Magazine. I hear they don’t carry the kit anymore, but someone Googled and found it by a company in Japan.

Here’s a video of it in action and here’s what it sounds like.

A teacher on a teacher listserv I’m on writes:

In my collection of Edison Phonographs I have many that will allow for purely mechanical reproduction of sound. I have an Edison tinfoil phonograph that records on tinfoil (duh) and numerous machines that record on wax cylinders. First the wax cylinder is shaved to a clean surface then a cutter head consisting of a diaphragm with a sapphire cutting stylus is lowered onto the record surface. As the cylinder turns, wax is cut by the stylus where the depth of the cut represents the wave pushing/pulling on the diaphragm. It is called the “hill and dale” or vertical cut type of recording.

The Gakken phonograph made in Japan uses a side by side motion or lateral recording. This is what the common 78 RPM records used from 1896 up through the mid-1950s. The toy phonograph does work but results vary depending on numerous factors. One is the temperature of the plastic cup used for the recording. I have found that a hair dryer warming the cup helps but one must be careful not to melt anything. The Gakken machine appears on eBay regularly under the search Edison Phonograph but shipping is as expensive as the machine is because it is air mailed from Japan. Maker Shed in the US carries it as well with some savings on postage but at a higher price.

tt_icon_170Have you ever really listened to the sound of a bouncing ball? There’s some elegant mathematics to be had in this simple thing. In this episode of my Science Teaching Tips podcast, staff educator and physicist Tom Humphrey takes us to the most perfect bouncing ball I’ve ever seen (or heard) — an exhibit at the Exploratorium. The platform the ball is bouncing on is a huge chunk of heavy marble, bolted to the floor. (What does that have to do with anything? Think about conservation of energy and momentum). You hear some surprising things as a small metal ball bounces on that surface. Even without the exhibit, this is something you can do with your students, and integrate science and math into your curriculum.

Listen to the episode – Follow the bouncing ball

tt_icon_170Despite my better judgment, I invite TI staff educator Eric Muller to do one more set of activities on my Teaching Tips podcast —several things you can do with soda straws.  Listen to the episode – The Last Straw.


Holding Charge activity (PDF)
More of Eric Muller’s activities