Posts Tagged ‘Physics’

Ferrofluid patterns and dancing art, fun with magnets

// April 29th, 2011 // 1 Comment » // How Things Work, Just for Fun, Science Art

Behold ferrofluid, nanoparticles of iron coated in a surfactant and suspended in a solution of oil or water.

The surfactant can be citric acid or soy lecithin, among other things, and is used to stop them sticking together

It’s like magnetic dust.

Put a magnet under some ferrofluid and the particles align themselves in patterns to show the field.

The magnetic attraction is so strong, the ferrofluid will stick to a magnet and then you’ll never get all the iron particles off it. They’re stuck for good.

To prevent that happening, people usually play with ferrofluid inside a sealed container.

And play it is, this stuff is fun.

Usually.

A friend of mine put a magnet above some ferrofluid with the lid off, and was abruptly COVERED in black gunk which stuck to him despite three showers. He wasn’t too happy, I think it smelled pretty bad. Hardcore.

Like most hardcore stuff, it’s been turned into kickass art. This video pretty well blew my mind.

Sachiko Kodama and Yasushi Miyajima created the piece, two ferrofluid sculptures which move synthetically to music. The two towers are iron cores of electromagnets sitting in a pool of ferrofluid. Etched with a helix pattern, the ferrofluid can move up the tower if the magnetic field is strong enough, stretching out in spikes as it goes.

The strength of the electromagnet is linked to metadata in the music controlling the voltage and AC pattern. To correct for the time delay, the electromagnet controls starts early so the maximum size of spikes coincides with beats of the music.

The result is a choreographed pattern that dances and winds like a living thing.

You can buy ferrofluid from Emovendo.

Hat tip to @DrSkySkull, who bought some ferrofluid as a classroom demo and supplied the picture at the top of the article.

What is a light cone?

// November 28th, 2010 // 1 Comment » // How Things Work

Simultaneous is not simultaneous. Space and time do not exist. These, and other strange and wonderful things, are the hallmarks of Einsteins Theory of Relativity and what we’re talking about today.

A few days ago I got Request a Post which read:
ahoy there, cap’tun! a prawn from beneath your deck speakin’. could you do a post on Light Cones? yeh know, the stuff Stephen Hawking talks about in the second chapter of his ‘Brief History of Time’? i’d love to read a simplified version. i simply can’t wrap the wiki article around my head! danke!

Ahoy there Prawn! Danke for requesting and here be yer post.

Something can’t move through space without moving through time as well. The Theory of Relativity dispenses with time and space, and instead describes a new thing called Spacetime.

Imagine a train moving in a straight line to the Eastward. We can map its movement through Space, Time or best of all, Spacetime! Notice how much more epically cool Spacetime looks. This will be important later.

With our Spacetime graph, we map space horizontally and time vertically.

In the realz world, there are three dimensions of space – length, width and height. Thankfully there is only one dimension of time, and this runs from past to future (unless you’re looking backwards.) To graph something using all four dimensions is hard, so instead we just take two dimensions of space and make a horizontal plane, then map time vertically. This will make sense in a second.

Now imagine a flash of light. Say you were standing on a hill on a moonless night and turned on a torch for a second. The light would spread out in every direction, lighting first the bushes near by, then later the trees in the distance. If we think about it in just 2 dimensions we can draw it like this, kind of like ripples in a pond.

If we map time vertically, and stack these pictures up above each other, we get a cone. So a Spacetime graph looks like this. Notice again that it is epically cool.

So a light cone is a flash of light moving through Spacetime. Usually people draw it as two cones. The bottom one is light collapsing into a single event, and the top one is it exploding out again.

Image by Deibid

You might be thinking – why bother?

Because this is a more accurate way to imagine the world. It shows how the past can influence the present and the future. When light cones overlap, it means two objects or events interact with each other. Every event in the Universe has an associated light cone. It’s a mathematical way to represent the Universe, and the basis for lots of complex physics (such as curved Spacetime, and why simultaneous events are relative to the observer.)

The theory of relativity replaced the absoluteness of space and time with the absoluteness speed of light.

I hope this answers ye question Prawn. Find out more about awesome light cones here.

CERN trap 38 atoms of antimatter

// November 18th, 2010 // Comments Off on CERN trap 38 atoms of antimatter // Recent Research

Facility at CERN

For the first time ever, antimatter has been trapped by a magnetic field allowing it to be studied in detail.

The 38 atoms were antihydrogen, theoretically the same as hydrogen but having the opposite charge. Where hydrogen is made of one proton, one electron, antihydrogen is made with an antiproton and a positron.

Antihydrogen was first made at CERN in 1995, and in 2002 they could make large enough quantities for study. The problem is that matter and antimatter annihilate each other when they meet, so the antihydrogen is short lived. The ALPHA project has changed that. Using strong and complex magnetic fields stops the antimatter from coming in contact with any matter.

This technique allowed the antihydrogen to last for a tenth of a second, plenty of time to study the properties of antimatter.

Antimatter has always been a bit of a mystery. During the Big Bang, equal amounts of antimatter and matter should have been made. But for some reason, everything around us is made of matter and the antimatter seems to have disappeared.

The research was published yesterday in Nature online.

ResearchBlogging.orgAndresen, G., & et al (2010). Trapped antihydrogen Nature DOI: 10.1038/nature09610

Here’s the press release from CERN, and here’s a neat video all about it.

Day Two Nobel Prize Week – Physics goes to graphene

// October 5th, 2010 // Comments Off on Day Two Nobel Prize Week – Physics goes to graphene // Science Communication

Image by AlexanderAIUS

The Nobel Prize in Physics 2010 has just been awarded jointly to Andre Geim and Konstantin Novoselov “for groundbreaking experiments regarding the two-dimensional material graphene”

Graphene, aka “atomic level chicken wire” are carbon atoms packed into a 2D lattice. It’s not used to keep molecular chickens in their rightful place, but if it was it would be hardcore. The stuff is one of the strongest materials ever tested, 200 times the strength of steel.

It also has great potential in creating new kinds of chips and transistors, possibly faster than silicon. It’s also a great sensor, either for single molecule gas detection or for disease markers.

Sheets of graphene could help sequence DNA ridiculously fast, and they prevent the growth of bacteria. They could be used as hygienic covers for food. Plenty more potential applications can be found on Wikipedia. It’s exciting stuff.

Andre Geim is also known for his work on gecko tape – a super strong adhesive that mimics gecko’s feet and could one day let humans climb walls like a gecko.

The Particle Zoo – Gift Idea for a Physicist

// December 10th, 2009 // 1 Comment » // Just for Fun, Science Art

I came across this cool gift for a physicist, or anyone, because they are totally geeky and super cute.

charm_quark
Squee!

The Particle Zoo have soft quarks, leptons, nucleons, and theoreticals like the Higgs Boson and the Tachyon (which in the X-Files made time-travel possible!). PLUS they have the same range in antiparticles, which are kept on a seperate page to prevent mutual annihilation. They also have a pack for beta decay with a neutron that turns inside out to reveal a proton, and releases an electron, an electron anti-neutrino and a W-Boson.

It’s the attention to detail that really gets me, they are all weighted according to the particle weight, they all have neat stuff, like the W-boson is two sided, one positive (W+) and one negative (W-). For Christmas you can get mini-versions on ribbon as Christmas Decorations – nothing says I’m a massive physics geek than a Christmas tree spotted with quarks.

I think I’ve learned more about particle physics by searching this site than I did after year 12 physics. That wouldn’t be hard though.






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