Archive for the ‘Random facts and WTFs’ Category

People suggested “Quantum Levitation” as a topic for a blog post. I haven’t been studying Subatomic/Quantum Physics for over 2 years now and my knowledge of this subject hardly exceeds grade 12 Physics class, so, sorry if some of the things you read here seem incorrect or way too oversimplified. You’re always welcome to correct me and/or add some additional info and in-depth explanation.

So, I think that many of you have already seen this video:

The phenomenon demonstrated in this video has been known for almost 100 years now, and it’s been properly explained in mid-1930’s by German physicists.

See, when cooled to a certain temperature, some materials tend to convert into a state of superconductivity, in which all electrical charges can go through this material without delays and energy loses. Why? I’m not sure. Maybe it has something to do with the energy levels within atomic shells (where all their electrons “spin” in a quantum cloud), considering that the energy would be at a very minimum level under such temperatures (the temperature of liquid nitrogen, which they used to cool down this piece of sapphire in the video, is usually below -196 C), so there might be some weird things occurring.

Interestingly, when a material becomes superconductive, it “pushes” all the magnetic fields out of its body. So, when a ferromagnet is introduced to a cold superconductor, its magnetic force gets repelled, causing it to levitate near this superconductor. And it can also be moved across its surface with no friction whatsoever (as there is no physical contact between these two materials, and the magnetic fields don’t produce friction by definition), so it might be a very efficient mode of transportation one day (if you discount the cost of liquid nitrogen in such quantities, as well as the aerodynamic friction).

My explanation is way too oversimplified, and it doesn’t cover some key things observed in this video-demonstration (such as why the hell gravity has no visible effect on the magnet when it’s “fixed” in space and turned upside-down). I would be really thankful to hear a more in-depth explanation of this phenomenon.

Anyway, what’s the practical application of this? I’m not sure. Of course, hypothetically, you can come up with lots of fun stuff, such as quiet frictionless trains, aircrafts that are powered by magnetic fields alone (UFO, anyone?), some weird space rails (temperature is rather close to the absolute zero out there, so it wouldn’t be problem to turn a pile of metal into powerful superconductors, lol). But those are still nothing more than wild sci-fi fantasies (lol, again). We need to figure out lots of things and solve multiple purely engineering problems first….

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When I was in grade 11, I accidentally came up with a model which, if proven true, leads to a conclusion that there is a parallel universe with all of its physical space occupied by an infinite foot. The model now holds a fancy title “Negative Shoe-size theory”.

One day, during a lunch time at school, I was trying to visually imagine the dynamic model of how volume of foot changes with the shoe-size. I don’t remember why I was thinking about that on the day, but those thoughts were rather occupying.

So, when I got to shoe-size 1, I was seeing a tiny-tiny foot, only a few cubic centimeters in volume. Then the shoe-size zero came into my imagination, and the feet disappeared completely.

“Now”, I thought, “what if the shoe size went negative.” That would be hard to imagine, but I gave it a shot.

See, when dealing with shoe-size in terms of volume, there are really just two variables which depend on each other: the volume occupied by foot (which can range depending on a shoe size) and the volume that isn’t occupied by foot (which is, pretty much, infinite, considering that the borders of our Universe are physically unreachable). So, what happens if the shoe size goes negative? That’s right! These two variables invert! The free-from-foot volume in the Universe becomes limited by the shoe-size and the foot-volume becomes infinite. So, if we’re dealing with a negative shoe-size, we would have all the physical space occupied by one giant foot which would have an infinite volume, and we would have only a tiny fraction of space that would be free from foot. The volume of this free space will depend on the negative shoe size. If the shoe size is -6, then the free space will be relatively small, if the shoe size is -15, then the free space will be relatively bigger.

I drew this model on a piece of paper and started showing it to everyone.

Daniel Park was the first person, besides me, who understood it. He thought that it was kind of funny, but, nevertheless, totally pointless and stupid. I agreed.

I was later using this “theory” to troll my Physics, Chemistry and Math B teachers.

Ahhh… I miss the school days.

During World War II, British Airforce was sending hundreds of planes every day to the continent to combat Germans. Not many of them were returning home.

Most of the planes that were returning to the bases were badly damages by bullets and shell splinter. British engineers were carefully analyzing the data, trying to find any patterns. They observed that, statistically, planes were most likely to receive damage in the wings and tail areas. They also observed that damages to the fuel tank and the pilot cabin were quite rare.

Based on this data, they decided to add more armor to the wings and the tail section.

It didn’t help.

Their logic was right, but they failed to consider one vital thing: they were analyzing the successes, and not the failures. The most useful information was on the planes that didn’t return. It was actually the damage to the fuel tank and the pilot cabin that was fatal. And those planes that received bullets in all the other sections were just lucky.

Always try to analyze your failures! It’s important to know not only what works, but what doesn’t work as well. Avoiding mistakes is crucial during any project!

If you did bad on an essay, take it apart and see what went wrong in order to avoid the same mistakes in the future.

Don’t hesitate asking people for feedback. And try to give feedback to others as well. A rational critique is always helpful (though I often can’t get it from people… Australians seem to be excessively polite and tell people only the things they want to hear, avoiding giving unpleasant (though necessary) feedback and judgment)…

Remember how in Hollywood movies they always show submarines, which use red light to illuminate their control rooms?

Well, that’s not far from the truth, actually. Military submarines always use red light during night time, when it’s dark outside. But why red?

The answer lies in the physiology of the human eye.

There are two major types of color receptors on human retina: rods and cones.

Rods work only in dim light, allowing people to see in the dark (scotopic vision), while cones require bright light to function and are used for colour vision (photopic vision). In most cases, they can’t function at the same rate simultaneously (simply because colour-capturing cones need bright light to perform, while rods get screwed by excessive amount of light (the process known as bleaching)). It might take up to 30 minutes for a person to switch from photopic vision to scotopic vision.

Submarine crew has to keep both photopic vision (in order to be able to read all the control panels) and scotopic vision (in case if they have to look into a periscope during night time).

Now, lets look at the electromagnetic wave frequencies, which activate certain photorseptors on the human retina:

As you can see, 3 types of cones cover the entire visible spectrum (400-700 nm), while rods are only capable of getting turned on by the light waves, which are not longer than 640 nm. That leaves L-cones with approximately 60 nm long piece of visible spectrum, which can be handled without any overlapping with other photoreceptors.

640-700 nm electromagnetic waves appear red to us.

Night-vision rods are insensitive to red light, therefore they can not be bleached by it. So, using red light in dark conditions allows people to keep both photopic and scotopic visions without any overlaps and conflicts between these two systems. Pretty cool, eh?

Red light is also used during nighttime by pilots, tank crew members, old-school astronomers and some lab-workers, who experiment with photosensitive materials.

Cats (as well as many other nocturnal animals) have a very cool eye structure called tapetum lucidum, which is located behind photosensitive retina.

In humans, when the light hits retina, a very large portion of this light just goes through retina and gets “lost” (absorbed) by choroid.

In cats, however, this light gets reflected back by tapetum lucidum and hits retina for a second time, allowing a more efficient photoreception.

Such retinal illuminance gives cats night-vision abilities 5-8 times better than those of humans (and it also gives cats this spooky glowing-eyes effect).

By the way, it’s sort of similar to a human red-eye effect, which can be observed on some photos (it’s caused by pigments in the human choroid, which absorb everything but low-frequency light waves (red), which get reflected back to the camera and, thus, cause eyes to appear red).

Cats’ night vision is awesome, indeed. But nothing is perfect.

We, humans, have an extremely good colour vision (in comparison to nocturnal animals, who are mostly dichromats, meaning that they able to perceive only two primary colours). Our visual acuity is also supreme (cats are not capable of focusing on things in the same way we do because of their tapetum lucidum…. even if they had an intelligence close to ours, their vision would be too blurry to allow them to read anything :) ).

I think many of you have already seen this wonderful video:

***

I’ll definitively try to do this to my cat.

I mean, I’ve done this before (I always grab Mars this way and throw him outside when I catch him stealing food in the kitchen), but I never realized that it’s actually a deactivating reflex!

Hmmm.. This method might be useful in washing cats. Though, I don’t think it is even necessary to wash cats. I only washed mine once, when he caught some skin parasites.

He was a kitten back then.

Giving him a bath was a hard thing to do. It’s not a big secret that domestic cats hate water (because it screws with their protective layer of fat, which is located just under their coat). If only I knew about this way of neutralizing him back then…

Anyway, there is another method you, my dear cat lovers, can try when you want to wash your pet.

Pour some anti-flea shampoo into the toilet, throw your cat in and close the lid cover. Your cat will try to get out, moving and splashing water everywhere within the closed space, getting rid of all the dirt and skin parasites. After 3 minutes, just flush the toiled 2 times to wash all the shampoo away, and let your animal out. The cat is now clean.

Easy and effective.

Here is an interesting question that you can use to troll your high school Science/Physics teacher.

The train is moving with a velocity of 40 km/h. A person on the roof of that train is walking forward (in the direction of travelling) with a velocity of 5 km/h. So, this person’s velocity, in relation to a steady observer, is 45 km/h (because velocity of that train (40 km/h) + velocity of that person (5 km/h) would give a sum of 45km/h).  That’s pretty straightforward.

Now, imagine that a steady observer is shooting a beam of light that travels with the velocity of 299 792 458 m/s (approximately 3.904×10^8 km/h). A second person, who happens to be on the train, which moves at 40 km/h, is doing the same thing. Will the second beam of light travel 40 km/h faster than the beam of light shot by a steady observer? Will it actually exceed the speed of light itself? :)

Give this problem to someone to think about. The LOLs are guaranteed :)

Warning: This troll will fail if a person, whom you decided to troll, is familiar with the theory of general relativity.