Anyone can put out a candle by blowing on it. According to [Physics Girl], that method is old hat. She made an educational video that shows five different ways to put out a candle using–what else–physics.
You might not need alternate ways to put out a candle, but if you are looking to engage students in STEM (Science, Technology, Engineering, and Math), this video along with others from [Physics Girl] might spark interest.
Suspension bridges are far and away the target of choice in America’s action blockbusters. In just the past three years, the Golden Gate Bridge has been destroyed by a Kaiju, Godzilla, a Skynet-initiated nuclear blast, and a tsunami. Americans don’t build real bridges anymore, or maintain the ones that we have, but we sure love to blow them up in movies.
There is logic here: A disaster scene involving a famous bridge serves both to root the film in the real world and to demonstrate the enormity and the immediacy of the threat. The unmaking of these huge structures shocks us because many bridges have gained an aura of permanence in our collective consciousness. Although we know when the Brooklyn Bridge was built and who built it, we feel like it has always been there and always will be. The destruction of our familiar human topography is even more disturbing than the deaths of the CGI victims, and I’m not just saying that as a misanthrope who loves bridges.
However, in all of the planning, storyboarding, rendering, and compositing of these special effects shots, nobody pauses to consider how suspension bridges actually behave. I can accept messianic alien orphan superheroes and skyscraper-sized battle robots, but I will not stand for inaccurate portrayals of structural mechanics. It’s fine to bend the laws of physics if the plot warrants it, but most suspension bridge mistakes are so needless and stupid that their only function seems to be irritating engineers.
The Greek philosopher [Zeno of Elea] proposed that an arrow in flight was in fact not in motion and its visible movement is only an illusion. A simple example of this is to glance at an arrow in flight, doing this causes our mind to store a snapshot of a motionless arrow. [Zeno] further defended this argument by stating that if an object has to travel a finite distance to reach a destination then the finite distance can be divided in half and the object must first reach this halfway point before arriving at the destination. This process can be repeated an infinite number of times, creating an infinite number of points that the object must occupy before reaching the destination thus it can never arrive at the destination.
Whoa, that’s a bit heavy. Let’s take a second here to think about this and never arrive at the conclusion, shall we?
So what does a fancy mathematics parlor trick have to do with the fact that we have all seen an arrow arrive at its destination? Recent experiments conducted at Cornell University have in fact verified the Zeno Effect. Researchers were able to achieve this by having atoms suspended between lasers in temperatures ~1 nano degree above absolute zero so that the atoms arrange themselves in a lattice formation. As per usual in quantum mechanics when observed, the atoms had an equal possibility of being anywhere within the space of the lattice. However, when they were observed at high enough frequencies the atoms remain motionless, bringing the quantum evolution to a halt.
What if there was a job where you built, serviced, and prepared science demonstrations? This means showing off everything from principles of physics, to electronic theory, to chemistry and biology. Would you grab onto that job with both hands and never let go? That was my reaction when I met [Dan Rosenberg] who is a Science Lecture Demonstrator at Harvard University. He gave me a tour of the Science Center, as well as a behind the scenes look at some of the apparatus he works with and has built.
Continue reading “Demonstrating Science At Harvard University”
What hacker doesn’t want a plasma cutter? Even if you aren’t MacGyver, you can probably build this one in a few minutes using things you have on hand. The catch? You probably can’t cut anything more than tin foil with it, and it is probably more a carbon-air arc gouger (which uses plasma) than a true plasma cutter. Still, as [Little Shop of Physics] shows on the video, it does a fine job of slicing right through foil.
If you are like us, you are back now after getting four 9V batteries, some tin foil, a pencil lead, and some clip leads and trying it. If you have more self-restraint than we do, you might want to think about what you are going to put the tin foil over. In the video, they used a laundry basket and a rubber band, but anything that keeps the foil suspended would do the trick.
Although it isn’t really a practical plasma cutter, we were thinking about strapping something like this to a 3D printer and cutting foil stencils. The jagged edges on the video are, hopefully, more from being operated by hand and less from the jagged mini-lightning bolt vaporizing the foil.
Monday | 24 October 1927 | Brussels
While the official title of the 5th Solvay conference was “on Electrons and Photons”, it was abundantly clear amongst the guests that the presentations would center on the new theory of quantum mechanics. [Planck], [Einstein], [Bohr], [de Broglie], [Schrodinger], [Heisenberg] and many other giants of the time would be in attendance. Just a month earlier, [Niels Bohr] had revealed his idea of complementarity to fellow physicists at the Instituto Carducci, which lay just off the shores of Lake Como in Italy.
The theory suggested that subatomic particles and waves are actually two sides of a single ‘quantum’ coin. Whichever properties it would take on, be it wave or particle, would be dependent upon what the curious scientist was looking for. And asking what that “wave/particle” object is while not looking for it is meaningless. Not surprisingly, the theory was greeted with mixed reception by those who were there, but most were distracted by the bigwig who was not there – [Albert Einstein]. He couldn’t make it due to illness, but all were eager to hear his thoughts on [Bohr’s] somewhat radical theory. After all, it was he who introduced the particle nature of light in his 1905 paper on the photoelectric effect, revealing light could be thought of as particles called photons. [Bohr’s] theory reconciled [Einstein’s] photoelectric effect theory with the classical understanding of the wave nature of light. One would think he would be thrilled with it. [Einstein], however, would have no part of [Bohr’s] theory, and would spend the rest of his life trying to disprove it.
E = hv
Where E is the energy of the light quanta, h is Planck’s constant and v is the frequency of the light. The most important item to consider here is this light quanta, later to be called a photon. It is treated as a particle. Now, if you’re not scratching your head in confusion right about now, you haven’t been paying attention. How can light be a wave and a particle? Join me after the jump and we’ll travel further down this physics rabbit hole.
Continue reading “Quantum Mechanics In Your Processor: Complementarity”
In the high-voltage world, a Jacob’s ladder is truly a sight to behold. They are often associated with mad scientist labs, due to both the awesome visual display and the sound that they make. A Jacob’s ladder is typically very simple. You need a high voltage electricity source and two bare wires. The wires are placed next to each other, almost in parallel. They form a slight “V” shape and are placed vertically. The system acts essentially as a short-circuit. The voltage is high enough to break through the air at the point where the wires are nearest to each other. The air rises as it heats up, moving the current path along with it. The result is the arc slowly raising upwards, extending in length. The sound also lowers in frequency as the arc gets longer, and once [Gristc] tuned his system just right the sound reminds us of the Holy Trilogy.
We’ve seen these made in the past with other types of transformers that typically put out around 15,000 Volts at 30mA. In this case, [Gristc] supersized the design using a much beefier transformer that puts out 11,000 Volts at 300mA. He runs the output from the transformer through eight microwave oven capacitors as a ballast. He says that without this, the system will immediately trip the circuit breakers in his house.
In the demo video below, you can see just how large the arc is. It appears to get about 10 inches long before breaking with a sound different from any Jacob’s ladders we’ve seen in the past as well. Continue reading “11,000 Volt Jacob’s Ladder Sounds Like A Lightsaber”
