Sweeeeeet Aurora Video

I think auroras are one of the coolest things on the planet. Along with bacon and beer.

This video was featured on the Astronomy Picture of the Day website. Two words:

Awe. Some.

Robot Sets Record for iPhone Game

Cool video of a robot programmed to play the iPhone game “1to50” I saw via Popular Science.

The object is to simply press the numbers from 1 to 50 in the correct order as fast as you can.

The robot [the Adept Quattro] managed to do it in 6.67 seconds, which is roughly 7.5 numbers pressed per second.

The game is available for free, so I tried it myself. After 3 attempts my fastest time was 51 seconds. I am ashamed.

 

New World Record: Most Powerful Railgun

As opposed to a traditional gun, which uses a small explosion to propel a projectile at a target, a railgun uses and electromagnetic field.

If you can generate a strong enough magnetic field, the resulting force can hurl a projectile at unprecedented speeds and energies.

What a navy ship can do is pulse a large amount of electricity through two rails. This generates a huge magnetic field. The resulting magnetic force, called the Lorentz Force, is what accelerates the projectile.

This is a video I saw at Scientific American showing the old world record, which was set in 2008 with an energy of 10 megajoules.

A joule is a unit of energy. A megajoule is a million joules. To put that kind of energy in perspective, a typical 9mm bullet weights about 115 g. If you were to give that bullet 10 megajoules of energy, it would travel at a speed of over 13 kilometers per second! Thats about 8 miles per second!

Now, this new railgun can reach energies of 33 megajoules, a three-fold improvement. Here is the video for the new record which was set yesterday.

The railguns will be able to fire a projectile hundreds of miles at an average speed of roughly Mach 5, or 5 times the speed of sound. The advantages of using railguns means carrying dangerous chemical weapons are unneccessary, as well as being able to fire smaller weapons from a large distance.

MRI of Woman Giving Birth

MRI of Baby in the birth canal. Photo Credit: Charité Hospital

Wow. Just…wow.

A couple of days ago, a woman in Germany gave birth at the Berlin’s Charité Hospital while inside an MRI scanner

 so scientists could study the birthing process in more detail.

A hospital spokesperson said the entire procedure went well, and both mother and baby are doing well.

Researchers designed a special “open” MRI machine in order to accommodate the experiment. MRI’s are quite loud though, so the mother still had to wear earmuffs, and the procedure was stopped after the amniotic sac broke, in order to protect the baby’s hearing.

MRIs use large coils of wire to generate a strong magnetic field to image the body. Generally, the bigger the magnet means a better picture, so the opening in which the patients lie is as small as possible. In this case, it was more advantageous to have a more open design. A photo of the actual MRI machine used in this experiment was not given, but it would look something like this.

An "open" MRI machine. Photo Credit: Open MRI of Canada

So what was the point of all this? Scientists want to study the birth process better in order to understand what causes complications, and prevent them.

Experiments like this are going to continue, as 5 more mothers have volunteered for the procedure.

Man, how many times have I said I would write a post about the “Physics of MRI”? Quite a few…its coming I promise, cause I have a couple more cool MRI studies to share… stay tuned.

The Physics of Jumping Rope

63rd Annual Meeting of the APS Division of Fluid Dynamics Volume 55, Number 16 

Abstract: CX.00008 : The aerodynamics of jumping rope

Authors:

  Jeffrey Aristoff
    (Department of Mechanical and Aerospace Engineering, Princeton University)

  Howard Stone
    (Department of Mechanical and Aerospace Engineering, Princeton University)

We present the results of a combined theoretical and experimental investigation of the motion of a rotating string that is held at both ends (i.e. a jump rope). In particular, we determine how the surrounding fluid affects the shape of the string at high Reynolds numbers. We derive a pair of coupled non-linear differential equations that describe the shape, the numerical solution of which compares well with asymptotic approximations and experiments. Implications for successful skipping will be discussed, and a demonstration is possible.

[My comments: The authors built a robot jump rope device and controlled parameters of rope rotation rate, rope density, diameter, length etc. using high speed cameras, they developed equations to describe the motion of the jump rope.

“Our main discovery is how the air-induced drag affects the shape of the rope and the work necessary to rotate it,” says Princeton researcher Jeff Aristoff. “Aerodynamic forces cause the rope to bend in such a way that the total drag is reduced.” (Leaves do this too when they bend out of the wind.) This deflection or twisting is most important in the middle of the rope and the least at the ends. If the rope is too light it might not clear the body of the jumper. (From Physorg.com)

I hope they did a demonstration. My experience is that physics conferences can be a bit stuffy.]