Stories tagged Physical Science

Feb
22
2012

This article describes the results of a study conducted by the Australian Government, which says some Australians “may be raising their risk of skin cancer by avoiding sunscreen due to unfounded fears over nanoparticles.” The article went on to say that one third of the people surveyed had heard or read about the possible risks of nanoparticles, and that 13% of these people would be less likely to use sunscreen. At first, this seemed like a very interesting finding – people would rank nanoparticles higher than skin cancer on their personal risk meters! But as I examined the article a little more, I realized I have a few issues with the way it presented the results. A Discrete Request for Regulation: The Hoff is on board.
A Discrete Request for Regulation: The Hoff is on board.Courtesy Friends of the Earth Australia

First, the article makes it sound as if survey-takers were faced with the question, “would you rather risk getting skin cancer or use a sunscreen with nanoparticles in it?” In actuality, they were simply asked if they would be less likely to use a nanoparticle-based sunscreen, given the risks they’d heard about. I realize it is implied that if you don’t use sunscreen your chances of getting skin cancer increase, but when taking a survey, you’re probably just answering the question at hand: Would you be less likely to use a product that you’ve heard could by risky. These answers are also coming from a survey that repeatedly mentions the “possible risks of using sunscreen with nanoparticles” in various questions. It seems to me that hula hooping could start to sound risky by the end of a survey like that. “Have you heard or read about the possible risks of hula hooping? If you have heard or read about the possible risks of hula hooping, do the stories make you any less likely to hula hoop in general? Agree or Disagree: 1.) Hula hooping is risky to my health. 2.) Hula hooping is more risky to my health than not hula hooping 3.) I am scared to hula-hoop.” Ok, I exaggerate a little, but the way a survey is presented has an effect on the answers people provide.

I get that they’re trying to highlight the fact that some people perceive nanoparticle-based sunscreens as dangerous, and that’s an interesting finding- not because they would stop using sunscreen, but because the current weight of evidence suggests that the nanoparticles in sunscreens don’t penetrate the skin - they’re harmless to humans. Which brings me to my point that perhaps a more telling result of the study is the high number of people who said they didn’t know if nanoparticle-based sunscreens are risky, and needed more information before deciding whether to use them. The fact that some people perceive nanoparticle-based sunscreens as dangerous when the current scientific evidence suggests otherwise, supports the idea that people just don’t know enough about nanoparticle-based products.

Now, I’m not suggesting that all nanoparticle-based products are safe, across the board. I’m also not trying to downplay people’s concerns about this relatively new technology. In fact, I think a healthy dose of caution is a good thing when it comes to new technologies. I just think that fear comes from not knowing, and people’s concerns could be alleviated if they had more information. What is concerning is that the information isn’t exactly available. There are no regulations on nano products (though the FDA appears to be working on it), companies are not required to label their products as containing nanoparticles, and there are no standards in defining what a nano product is. What I am suggesting is that maybe we should be demanding that information from the likes of industries, governments, policy makers, etc, instead of focusing on the few that perceive nanoparticles as risky.

The point of the study was to figure out the public’s perception of sunscreens that contain nanoparticles, and I think it did. It showed that the public doesn’t know enough about it to make any real/informed decisions.

What’s your take? How do you feel about nanoparticles being used in products you rely on every day? What do you think about regulating this technology? Creating standards for it? Do you think these regulations and standards would stifle scientific progress, or protect our health? What do you think about hula hooping?

Sep
09
2011

As a physical science teacher, one of my jobs is to teach my students how to measure like scientists. This includes, but of course is not limited to, distance with a ruler and mass with a balance. That is why I like to do a lab with the density blocks very early in the year. You use the rule to measure the length, width, and height of the blocks (in this case they're cubes, but hopefully sometime the Resource House will get some non-cube blocks) to calculate volume. They get practice using the triple beam balance finding mass. Finally they get to calculate density and put the blocks in order by density. A fun and engaging way to learn about the importance of measurement. Oh yeah, it's totally free too (thanks Resource House).

May
10
2011

Sometimes we here at Nano Headquarters grow weary of reading and attempting to decipher scientific papers in ways that make them easy to understand.

Take, for example, this sentence:

“The as-prepared gold particles showed good catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol by excess NaBH4, and a surface-enhanced Raman scattering (SERS) study suggested that the gold nanoparticles exhibited a high SERS effect on the probe molecule Rhodamine 6G.”

Here’s what we were able to immediately comprehend:

“The as-prepared gold particles showed good BEEEEEEEP for the reduction of BEEEEEEEP to BEEEEEEEP by excess BEEEEEEEP, and a surface-enhanced BEEEEEEEP BEEEEEEEP BEEEEEEEP study suggested that the gold nanoparticles exhibited a high BEEEEEEEP effect on the probe molecule BEEEEEEEP BEEEEEEEP”

On days like this, we like to practice what we call "selective avoidance" and seek out pretty images instead. Pretty nano-related images, mind you – but pretty images nonetheless. They soothe our bleeding brains. And so, for your BEEEEEEEP-free pleasure, we offer you this here compendium of pretty nano images:

Pretty!: Pollen Grains
Pretty!: Pollen GrainsCourtesy Dartmouth Electron Microscope Facility

NOVA - The Art of Nanotech
Remember our friends over at NOVA who made the nanorrific Making Stuff series? This here slideshow was a little buried treasure accompanying it. The images are originally from the Materials Research Society - Science as Art competition. We’re a little partial to the Starry Night knockoff. Van Gogh would be impressed. And if not, then we wouldn’t have wanted to be his friend anyway because apathy gets boring fast and huffy, stuffy artists are tedious.

Sciencescapes Speaking of the Science as Art competition – here are a few more images from competitions in years past. From likenesses of spaghetti and meatballs to a decaying Santa to a creepy Pac-Man to a dotted-dude walking off a cliff to his ultimate doom, there’s a little something here for everyone.
Also Pretty!: Water Droplet on Nasturtium Leaf
Also Pretty!: Water Droplet on Nasturtium LeafCourtesy Stephan Herminghaus

International Science and Engineering Visualization Challenge
A video from the National Science Foundation wherein they invite us to “discover the artistry behind the 2010 International Science & Engineering Visualization Challenge winners as they explain the processes, techniques and thoughts behind their entries.” SPOILER ALERT: The very first fellow we meet tells us right out that there’s “no message” to his work. Awesome.

Silver Saver – nanotech in art preservation Think that the old, old artifacts you see in museums just stay that way because they’re in a fancy, climate-controlled case? Think again!
Equally Pretty!: Silicon Nanomembrane
Equally Pretty!: Silicon NanomembraneCourtesy S. Scott, University of Wisconsin-Madison

NISE Net Viz Lab All the pretty, pretty pictures you’ve seen in this post thus far are from the NISE Net Viz Lab. And guess what? They’re in the public domain! That means you can use them however you like without going through all sorts of crazy legal hoops! Whee! Just remember to give credit where credit it due – ‘cause we’re pretty sure you don’t have a scanning electron microscope at home.

SPECIAL NOT-NECESSARILY-NANO BONUS:
The Periodic Table Printmaking Project We could look at these for DAYS. In fact, we have. Take the Periodic Table of the elements, mix in a few block-print makers, and what do you get? Some seriously killer prints that provide visual intrigue for such favorites as Promethium and Fluorine. We will admit to getting a little googley-eyed over these.

Okay kids, stop swooning. Back to work.

Sep
05
2010

Quest for the best optical display

Better resolution displays
Better resolution displaysCourtesy Yutaka Tsutano

I have been waiting for the new iPod Touch. I want a display screen so sharp, it looks like a photograph. The "retina display" creates an image out of pixels that are only 78 nanometers. How small is that? Well, more than 300 of these pixels are packed in each inch. Supposedly this is the limit for human perception, or as some fanboys might say, "It doesn't get any better than this!"

Plasmonic nanoresonators

University of Michigan researchers can do better, though, Their paper in Nature Communications titled, Plasmonic nanoresonators for high-resolution colour filtering and spectral imaging explains how pixels of only 10 microns can be produced.

Such pixel densities could make the technology useful in projection displays, as well as wearable, bendable or extremely compact displays, according to the researchers.

How does it work?

The resonators are kind of like a light filter. Two nano thin layers of metal selectively allow light to pass through small sets of slits. The slit spacing determines which wavelength of light makes it through the slits.

Red light emanates from slits set around 360 nanometers apart; green from those about 270 nanometers apart, and blue from those approximately 225 nanometers apart. The differently spaced gratings essentially catch different wavelengths of light and resonantly transmit through the stacks. LinuxForDevices.com

These displays are simpler, use fewer parts, are more efficient, and should be cheaper to make. I am not going to wait, though.

Aug
03
2010

Aurora borealis above Lake Harriet in Minneapolis, MN: The white streak visible in the lower right of the timed exposure is an aircraft taking off from the Minneapolis-St. Paul airport.
Aurora borealis above Lake Harriet in Minneapolis, MN: The white streak visible in the lower right of the timed exposure is an aircraft taking off from the Minneapolis-St. Paul airport.Courtesy Mark Ryan
Old Sol could be stirring up the atmosphere this evening with a display of northern lights (aurora borealis). Scientists have recorded a significant burst of plasma shooting from the Sun’s surface that could mean we earthlings are in for a light show tonight or early Wednesday morning. The solar wind particles are headed right toward us, and when they reach the Earth’s magnetic field they’ll interact with atoms of nitrogen and oxygen in the atmosphere and - hopefully - produce glowing sheets and fingers of green, red, blue, or even yellow in a wonderful display in the northern skies. The southern hemisphere experiences the same phenomenon but down there it’s known as the aurora australis (southern lights).

Lately, here in the Twin Cities, the air has been supersaturated with humidity so I don’t know how crisp a view we’ll get but it could be worth stepping outside tonight to see what’s up.

SOURCE and LINKS
CNN.com report
Univ. of Alaska’s Geophysical Institute Aurora Forecast page
Michigan Tech’s Aurora page
Solar flares

Jun
03
2010

Sophisticated forecast modeling tools developed at the Center for Coastal Margin Observation & Prediction (CMOP) were recently used to assist in the rescue of a disabled underwater glider.

CMOP researchers spent two days using a particle-tracking model to predict where and when their glider, nicknamed “Phoebe,” would drift ashore. This helped researchers understand how much time they had to stage a recovery operation.

Rescue planning: This is an example of the particle tracking model used to predict the direction the glider would drift. Red represents the glider GPS signals. Green represents the particle tracking forecast.
Rescue planning: This is an example of the particle tracking model used to predict the direction the glider would drift. Red represents the glider GPS signals. Green represents the particle tracking forecast.Courtesy CMOP

“Once Phoebe became a drifting glider, we treated her as a major piece of scientific instrumentation at risk and an opportunity to test our computer models in a sea emergency,” says Antonio Baptista, director of CMOP. “The forecasting system used for Phoebe is the same that we are currently transferring to the U.S. Coast Guard and NOAA (National Oceanic and Atmospheric Administration) for inclusion in their respective operational and emergency response systems.”

Phoebe is a bright yellow glider that moves through the water, gathering information, and sending satellite signals back to land each time she surfaces. She was sent out on her first mission of the year on April 16, 2010 to collect data in the waters off the Washington coast as a collaborative research effort with the Quinault Indian Nation.

Five days into her mission, Phoebe stopped communicating.

Katie Rathmell and Michael Wilkin, members of the CMOP field team in Astoria, Oregon, waited and hoped to receive a signal from her. Hours passed and still no signal. Then almost 24 hours later, Phoebe called home. She had surfaced and transmitted a GPS signal of her current location.

“We reviewed the files she sent and determined that she had gotten stuck at 8.4 meters below the surface and was unable to come up to the surface,” says Rathmell.

The team theorized that Phoebe got tangled in a kelp bed. After a pre-programmed period of time, she jettisoned her emergency ballast weight, which gave her enough buoyancy to escape the entanglement and surface. But having dropped the ballast weight meant she could no longer dive or maneuver. Phoebe was adrift in the ocean.

Rathmell and Wilkin started talking about how to stage a rescue. The challenge was the gale force winds offshore were making the seas too rough for ships to get out of the harbor. The team would have to wait until weather conditions improved.

Even though Phoebe was disabled, she was capable of transmitting a GPS signal every 30 minutes. This allowed the team to track her location. She was drifting south and getting closer to the Columbia River plume. They were concerned she might get caught in the incoming tide. This would pull her into the river and possibly crash her into the jetty. Currents and winds could also push her onto the beach and the surf could break up the glider. The problem was the team was unsure which direction she would drift.

That is when they made the decision to use CMOP’s modeling tools to help narrow down Phoebe’s potential drifting trajectories, possible threats, and windows of time for a recovery operation.

“The team hoped the weather would break in time for a successful recovery. The models helped predict how much time they had to recover Phoebe,” says Paul Turner, senior research programmer.

The data for the particle tracking comes from the forecast models that CMOP runs on a continuous basis. Turner ran simulations for two days using the winds, currents and tides to predict where Phoebe might end up. He generated graphs that predicted drifting directions in one, two, three and four hour intervals.

“Paul Turner did a very good job of getting the modeling and drifter prediction tools working in a fashion that allowed the data to be useful for us,” says Wilkin.

The forecast model showed that time was running out for Phoebe. The prevailing winds and currents were pushing her closer to shore. It was imperative to rescue her soon.

For several days, the conditions were too dangerous to cross the Columbia Bar and get the glider safely aboard a ship. Then around 10:30 on Sunday morning, the research team received word there was a break in the weather and Captain Dan Schenk from Sea Breeze Charters in Ilwaco, Washington would take them out.

Rathmell and Wilkin boarded the “Nauti-Lady” and took a rough ride over the Columbia Bar en route to Phoebe’s last known location.

Finding Phoebe was a challenge. This time of year there are crab traps set out in the ocean and many of their floats are the same color as Phoebe. The team would spot something on the surface of the water that might be Phoebe but it turned out to be something else.

Then they spotted her tangled up in crab lines and floats. “She was surrounded by kelp, plastic, beer bottles, and all sorts of trash,” says Rathmell. They were successful in getting hold of her, removing the crab lines, and pulling her aboard the ship. The team safely returned Phoebe to shore.

Found!: "Phoebe" was found tangled in kelp and crab lines off the Washington coast.
Found!: "Phoebe" was found tangled in kelp and crab lines off the Washington coast.Courtesy CMOP

“The successful rescue of Phoebe, under difficult sea conditions, is a credit to the team work among the Astoria field team, boat operators, modelers and programmers,” says Baptista. “CMOP’s oceanographic knowledge, field observations, computer models, and cyber infrastructure all came together to allow people to make the right decisions at the right time.”

CMOP will use the lessons learned from Phoebe’s rescue operation to further improve their scientific and engineering infrastructure.

Jun
03
2010

Back when BP was still trying the "top kill" method of slowing the flow of oil into the Gulf of Mexico, the news was full of references to "drilling mud."

Make some oobleck: It won't stop the oil flowing into the Gulf of Mexico, but it's fun, and you'll learn something about non-Newtonian fluids while you're at it.
Make some oobleck: It won't stop the oil flowing into the Gulf of Mexico, but it's fun, and you'll learn something about non-Newtonian fluids while you're at it.Courtesy JoshSchulz

This stuff is no ordinary mud. It helps a rig drill faster and keeps the equipment cool and lubricated, but it's got some wacky other properties. It's a non-Newtonian fluid. That means its viscosity changes as you apply stress. If you punch or hit a shear thickening non-Newtonian fluid, the atoms in the fluid rearrange themselves in such a way that the liquid acts like a solid. A shear thinning non-Newtonian fluid (like ketchup or toothpaste) behaves the opposite way, getting thinner and drippier under stress.

Still don't quite get it? Check this video:

When they're running--applying a stress whenever their feet strike the surface--the fluid acts like a solid and they can walk on top of it. But when he stands still....

The Mythbusters have played with this phenomenon, too:

So. Drilling mud behaves kind of the same way. Here's Bill Nye explaining it all on CNN. When the drilling mud passes through a narrow opening, under pressure, it locks up and acts more like a solid. The idea was that if BP could pump a water-based drilling mud into the ruined well head and get it to solidify, then they could slow the flow of oil enough that engineers could encase the whole thing in cement. It didn't work. That's because the oil and gas spewing out of the pipe are under tremendous pressure. BP engineers just couldn't pump enough mud in there to stop the oil.

Depressing, huh?

But oobleck isn't. What's oobleck? It's a non-Newtonian fluid you can make and play with at home.
Instructables tells you how.

May
24
2010

The theremin: An apropos sign adorns the instrument at the Bakken Museum of Electricity in Minneapolis, MN, since it can only be played by not touching it.
The theremin: An apropos sign adorns the instrument at the Bakken Museum of Electricity in Minneapolis, MN, since it can only be played by not touching it.Courtesy Mark Ryan
Anyone who has ever watched a 1950s science fiction film has probably heard the eerie emanations of the electronic instrument known as the theremin. It’s that high-pitched wavering tone that usually accompanied radioactive giant insects, or flying saucers and spacemen (e.g. The Day the Earth Stood Still). It can also be heard creating the good vibrations in the Beach Boy’s song of the same name, I remember seeing Simon & Garfunkle in concert a few years back, and noticing that the instrument was used during the performance of their song The Boxer.

I don’t remember when I first became aware of the device. I suppose it was in those aforementioned sci-fi movies. The electronic instrument (the first of its kind) was created by Russian professor Leon Theremin in 1917, when he stumbled upon it while trying to construct a better radio. Theremin was also a musician and obviously saw potential in his accidental invention.

The theremin is an odd-looking thing made up of a box containing circuitry, some knobs, and two metal antennas, one straight, and the other looped. Rather than strumming, bowing or hammering strings, or blowing air into brass tubes or across reeds, the sounds of the theremin are produced by not touching it. Here’s how it works: inside the theremin’s circuitry guts, two radio frequency oscillators produce two distinct signals. It’s the mixing of these two signals in a process called heterodyning that create the theremin’s sounds. The performer stands near the unit and controls the pitch and volume by moving their hands in the vicinity of the two antennas. Generally, the left hand controls the volume over the looped antenna, and the right hand the pitch near the straight antenna, although some performers, such as virtuoso Pamelia Kurstin, reverse the antennas (I’m guessing the instrument can be constructed for both right-handed and left-handed people). Changes in pitch and volume are controlled by the performer moving his or her hands nearer or farther from their respective antenna. In Kurstin’s case, the closer her left hand moves towards the straight antenna, the higher the pitch in tone, while the farther her right hand moves from the looped antenna, the louder the volume. Musical techniques such as vibrato and staccato can be mastered and controlled by rapid hand movement,

In this TED Talk performance (which got me interested in this subject), the above-mentioned Pamelia Kurstin shows that the theremin is not limited to just special effects. She has mastered the instrument to the point of being able to create dreamy and haunting melodies, as well as simulate a walking bass line as she does in the first song, Autumn Leaves. You’ll notice Pamelia appears to be in a trance while playing the instrument, but as she explains she’s keeping as still as possible so as to not corrupt the tone production. Unintentional body movements or even her breathing can affect the tone she’s trying to produce.

The Bakken Museum of Electricity in Minneapolis has a working theremin on display that visitors can play. Making sounds on the instrument is pretty easy but making music is a completely different story. Like the human voice, the violin, or similar instruments, the theremin allows for what’s called portamento, that is the gliding between a range of tones. You’re not limited by frets or keyboards, and have to sense your way from one note to the other. If you ever get a chance to play an actual theremin you’ll realize just how difficult it is.

Thereminvox.com
Official Pamelia Kurstin website
Pamelia Kurstin on MySpace Music
Some guys performing a theremin jam of Gnarls Barkely's Crazy

May
21
2010

Holy cow, Buzzketeers. The oil spill news just keeps coming! I can hardly keep up READING about it, much less BLOGGING.

So I'm going to leave you this weekend with a series of cool links, and you and I can read together.

Start with this mind-boggling plethora of interactive features and graphics from the NYTimes Gulf of Mexico oil spill multimedia collection.

An interactive map tracking the Gulf of Mexico oil spill, plus: video, graphics, and photos."

Size of oil spill underestimated, scientists say (5/13/10)

"Two weeks ago, the government put out a round estimate of the size of the oil leak in the Gulf of Mexico: 5,000 barrels a day. Repeated endlessly in news reports, it has become conventional wisdom.

But scientists and environmental groups are raising sharp questions about that estimate, declaring that the leak must be far larger. They also criticize BP for refusing to use well-known scientific techniques that would give a more precise figure."

BP boss admits job on the line over Gulf oil spill (5/14/10)

"Tony Hayward, the beleaguered chief executive of BP, has claimed its oil spill in the Gulf of Mexico is "relatively tiny" compared with the "very big ocean".

In an bullish interview with the Guardian at BP's crisis centre in Houston, Hayward insisted that the leaked oil and the estimated 400,000 gallons of dispersant that BP has pumped into the sea to try to tackle the slick should be put in context.

"The Gulf of Mexico is a very big ocean. The amount of volume of oil and dispersant we are putting into it is tiny in relation to the total water volume," he said."

Giant plumes of oil forming under the Gulf (5/15/10)

"Scientists are finding enormous oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick in spots. The discovery is fresh evidence that the leak from the broken undersea well could be substantially worse than estimates that the government and BP have given."

BP reports some success in capturing leaking oil (5/17/10)

"NEW ORLEANS — After more than three weeks of efforts to stop a gushing oil leak in the Gulf of Mexico, BP engineers achieved some success on Sunday when they used a milelong pipe to capture some of the oil and divert it to a drill ship on the surface some 5,000 feet above the wellhead, company officials said."

Conflict of interest worries raised in spill tests (5/20/10)

"Local environmental officials throughout the Gulf Coast are feverishly collecting water, sediment and marine animal tissue samples that will be used in the coming months to help track pollution levels resulting from the Deepwater Horizon oil spill.

Hundreds of millions of dollars are at stake, since those readings will be used by the federal government and courts to establish liability claims against BP. But the laboratory that officials have chosen to process virtually all of the samples is part of an oil and gas services company in Texas that counts oil firms, including BP, among its biggest clients."

Agency orders use of a less toxic chemical in Gulf (5/20/10)

"GRAND ISLE, La. — Local and state officials here voiced desperation on Thursday as their fears became far more tangible, with oil from the BP spill showing up on shore as tar balls, sheens and gooey slicks.

In Washington, the Environmental Protection Agency said it had told the oil company to immediately select a less toxic dispersant than the one it is now using to break up crude oil gushing from a ruined well in the Gulf of Mexico. Once the agency has signed off on a different product, it said, the company would then have 72 hours to start using it."

Environmental fallout from Gulf oil spill (5/20/10)

"The release of millions of gallons of oil into the Gulf of Mexico could have profound effects for wildlife and aquatic life, and now is threatening to go beyond the Gulf. Midmorning looks at the impact of the spill."

And last, but not least, here's the relevant page on the website of the Select Committee on Energy Independence and Global Warming, which has a nice aggregator of oil spill news, along with video from the ocean floor.

May
13
2010

He's fusing hydrogen isotopes in his brain right now: Such is the power of Kim Jong-Il.
He's fusing hydrogen isotopes in his brain right now: Such is the power of Kim Jong-Il.Courtesy JJ Georges
Check it out: North Korea claims to have produced nuclear fusion. Fusion has been demonstrated in laboratory experiments, and, as I understand it, fusion can be achieved in fission-based nuclear weapons, but scientists have never been able to create it on the right scale to produce lots of cheap, controlled energy (for electrical power generation, which is sort of the ultimate goal.) Except, you know, North Korea now.

(Fusion, by the way, is all about forcing two light atoms to merge together. The atoms have to release some of their components to do this, and when those components go flying off, there's a lot of energy to be had from them. More or less.)

Some folks are pointing out that North Korea is one of the poorest countries in the world, and they can barely get their national act together in a lot of other ways, so it seems very unlikely that they've made any huge advancements towards fusion power (which has eluded scientists around the world for decades). But you never know. After all, they claim that the discovery coincided with the birthday of North Korea's "Dear Leader," Kim Jong-Il, and stranger things have happened on that day—according to official biographies, a new star appeared in the sky on the day Jong-Il was born.

la la la