“It should remain airborne until until gravity overtakes it” is an awkward way of explaining. Gravity is always there, so the acceleration is always toward the earth. That’s why it slows down and eventually changes direction.
There is a world championship for anvil launching?
If this were Wile E. Coyote, no matter where he ran, the anvil would land on him.
A while back, gg explained Earnhsaw’s theorem and the application to magnetic levitation; you can’t trap a dipole with static fields. But that’s OK, because you want a time-varying field so that you can transfer the energy via induction. The bulb is modified to do this.
another h/t to Buzz’s owner
Some laser porn at Built on Facts. Seeing Laser Beams
This is used to pump an infrared ultrashort-pulse laser with a repetition rate of 1 kHz. This can itself be focused to a point in the air, which becomes visible as a little stationary spark as the intense beam ionizes the air. This produces a 1 kHz buzz which can easily be heard by the unassisted ear.
That’s the atomic physics version of geek seduction.
Following the drops dancing on a water surface, I was sent a link to drops jumping around on a super-hydrophobic surface:
A sphere is the minimum energy configuration, and this energy scales with surface/volume ratio; small spheres combining will represent a change in energy, and this energy shows up as a vibrational mode of the droplet, so it can launch itself off of the hydrophobic material. Bigger drops don’t display the behavior because the energy released is smaller in proportion to the mass that’s present.
Like so many things in science, it is probably obvious in hindsight that it has to be this way, but the real trick is thinking of looking for it ahead of time.
In an earlier post we saw other drop dynamics in microgravity that shows the vibrations when drops combine.
h/t to Tea With Buzz
Making light rays in the classroom
Laser level as the source, and lenses using gelatin as the medium, to demonstrate Snell’s law.
The sand skink, Plestiodon reynoldsi, is famous for its ability to swim through sand at depths of up to 10 centimetres. That’s strange because although sand sometimes act like a fluid, it also acts as a solid supporting large loads such as human footfall. So how do sand skinks do it?
Today, Takashi Shimada at the University of Tokyo in Japan and a few buddies reveal the secret. They say that the sand skinks’ swimming action exploits sand’s fluid-like nature AND its ability to act like a solid. And they’ve built a computer model to simulate how this works.
Why doesn’t the sand skink sink?
I just ran across The 10 weirdest physics facts, from relativity to quantum physics, and as I just finished up an antiscience piece, I thought I’d just turn this into a little Friday rant-o-thon.
Zapperz also ran across this, and rightly notes that nitpicking the details probably won’t matter to non-physicists, because they aren’t likely to pick up on such subtleties. But hey, this is the blogohedron. When nitpicking is out, ranting is in.
The thing you lose with stories like these is that there so much more you could get from them, but the author is admittedly a nonscientist and is missing out on a lot of the neat stuff that live in the details. He’s content to point out some things that are odd, especially when viewed through the prism of the limited everyday-classical-physics experience. The real problem in this is perpetuating misunderstandings of physics. Zz points out a big one — sustaining the concept of relativistic mass. There’s also the insistence that observing can change the past, and one of the new standards, entanglement. Thank goodness teleportation wasn’t mentioned.
Energy Secretary Steve Chu visits the Googleplex to talk about how the U.S. can build a prosperous economy powered by clean energy.