Latest Posts by optimisticcloudgarden - Page 2
Good wood - um, I’m currently trying to work out if this is the coolest bit of tech that’s ever been on here…. I think it might just be. Beautiful, classy, classic but contemporary, it makes you feel like you’re from the 1940s, 1970s and 2020 all in one go. Yes please!
Beautiful proofs (#4) - When Gauss was a young child...
The legend goes something like this:
Gauss’s teacher wanted to occupy his students by making them add large sets of numbers and told everyone in class to find the sum of 1+2+3+ …. + 100.
And Gauss, who was a young child (age ~ 10) quickly found the sum by just pairing up numbers:
Using this ingenious method used by Gauss allows us to write a generic formula for the sum of first n positive integers as follows:
Name them all? 😍 @guntrends 📷 @buffalodiller
“I respect orders but I respect myself too and I do not obey to foolish rules made especially to humiliate me.”
— Jean-Paul Sartre
“Most people do not listen with the intent to understand; they listen with the intent to reply.”
— Stephen R. Covey
Hoplia Coerulea
I never change, I simply become more myself.
The world will ask you who you are, and if you don’t know, the world will tell you.
Carl Jung (via quotemadness)
Learn from me, if not my precepts, at least by my example, how dangerous is the acquirement of knowledge, and how much happier that man is who believes his native town to be the world, than he who aspires to become greater than his nature will allow.
Mary Shelly , Frankenstein (1818)
Good wood - more irregular angles, this time on the outskirts of the garden city of Damavand, Iran. Damavand Villa by resident architects Shirazian Studio.
Be wise, always!
You wear a mask for so long, you forget who you were beneath it.
Alan Moore (via quotemadness)
Set Fire To The Lithium
Physicist Create a Fluid With Negative Mass
Physicists from Washington State university have created a liquid with negative mass meaning that when you push it, instead of accelerating in that direction, it accelerates backwards.
Matter can have a negative mass much the same way that particles can be negatively charged. Newton’s second law of motion (F=ma) tells us that mass will accelerate in the direction of the force so we can deduce that matter with a negative mass would do the opposite and accelerate against the force.
To create the conditions for negative mass, Peter Engels and his team started by cooling rubidium atoms to a Bose-Einstein condensate meaning they reached very near absolute 0. The researchers used lasers to trap the atoms in an area less than 100 microns across and allow high energy particles to escape cooling them further. Then to create negative mass, the physicists applied a second set of lasers to change the way atoms spin back and forth. They then removed the first set of lasers causing the rubidium to rush out and appear to hit some sort of invisible wall; behaving as if it had a negative mass.
What’s great about this is the control we have over the negative mass without any other complications. This gives us a new tool we can use to engineer experiments in astrophysics looking at neutron stars, black holes, dark energy and a lot more.
“Solitude is dangerous. It’s very addictive. It becomes a habit after you realize how peaceful and calm it is. It’s like you don’t want to deal with people anymore because they drain your energy. “
Jim Carrey
Before you change the world, change yourself
Yesterday I as clever, so i wanted to change the world. Today I am wise, so I am changing myself.
Work hard in silence; let success make the noise.
Your heart is the size of a fist because you need it to fight.
Lora Mathis (via quotemadness)
Dear me, silence is not a song you should know all the words to.
Shane Koyczan (via quotemadness)
She’s like smoke: you think you’re seeing her clearly enough, but when you reach for her there’s nothing there.
Ryū Murakami (via quotemadness)
In their newest video, the Slow Mo Guys recreated one of my favorite effects: vibration-driven droplet ejection. For this, they use a Chinese spouting bowl, which has handles that the player rubs after partially filling the bowl with water. By rubbing, a user excites a vibrational mode in the bowl. Watch the GIFs above and you can actually see the bowl deforming steadily back and forth. This is the fundamental mode, and it’s the same kind of vibration you’d get from, say, ringing a bell.
Without a high-speed camera, the bowl’s vibration is pretty hard to see, but it’s readily apparent from the water’s behavior in the bowl. In the video, Gav and Dan comment that the ripples (actually Faraday waves) on the water always start from the same four spots. That’s a direct result of the bowl’s movement; we see the waves starting from the points where the bowl is moving the most, the antinodes. In theory, at least, you could see different generation points if you manage to excite one of the bowl’s higher harmonics. The best part, of course, is that, once the vibration has reached a high enough amplitude, the droplets spontaneously start jumping from the water surface! (Video and image credits: The Slow Mo Guys; submitted by effyeah-artandfilm)
“If there is energy within the substance it can only come from without. This truth was so manifest to me that I expressed it in the following axiom: ‘There is no energy in matter except that absorbed from the medium…’ If all energy is supplied to matter from without then this all important function must be performed by the medium.”
“When radio-active rays were discovered their investigators believed them to be due to liberation of atomic energy in the form of waves. This being impossible in the light of the preceding I concluded that they were produced by some external disturbance and composed of electrified particles. My theory was not seriously taken although it appeared simple and plausible. Suppose that bullets are fired against a wall. Where a missile strikes the material is crushed and spatters in all directions radial from the place of impact. In this example it is perfectly clear that the energy of the flying pieces can only be derived from that of the bullets. But in manifestation of radio-activity no such proof could be advanced and it was, therefore, of the first importance to demonstrate experimentally the existence of this miraculous disturbance in the medium. I was rewarded in these efforts with quick success largely because of the efficient method I adopted which consisted in deriving from a great mass of air, ionized by the disturbance, a current, storing its energy in a condenser and discharging the same through an indicating device. This plan did away with the limitations and incertitude of the electroscope first employed and was described by me in articles and patents from 1900 to 1905. It was logical to expect, judging from the behavior of known radiations, that the chief source of the new rays would be the sun, but this supposition was contradicted by observations and theoretical considerations which disclosed some surprising facts in this connection.
“Light and heat rays are absorbed in their passage through a medium in a certain proportion to its density. The ether, although the most tenuous of all substances, is no exception to this rule. Its density has been first estimated by Lord Kelvin and conformably to his finding a column of one square centimeter cross section and of a length such that light, traveling at a rate of three hundred thousands kilometers per second, would require one year to traverse it, should weigh 4.8 grams. This is just about the weight of a prism of ordinary glass of the same cross section and two centimeters length which, therefore, may be assumed as the equivalent of the ether column in absorption. A column of the ether one thousand times longer would thus absorb as much light as twenty meters of glass. However, there are suns at distances of many thousands of light years and it is evident that virtually no light from them can reach the earth. But if these suns emit rays immensely more penetrative than those of light they will be slightly dimmed and so the aggregate amount of radiations pouring upon the earth from all sides will be overwhelmingly greater than that supplied to it by our luminary. If light and heat rays would be as penetrative as the cosmic, so fierce would be the perpetual glare and so scorching the heat that life on this and other planets could not exist.
“Rays in every respect similar to the cosmic are produced by my vacuum tubes when operated at pressures of ten millions of volts or more, but even if it were not confirmed by experiment, the theory I advanced in 1897 would afford the simplest and most probable explanation of the phenomena. Is not the universe with its infinite and impenetrable boundary a perfect vacuum tube of dimensions and power inconceivable? Are not its fiery suns electrodes at temperatures far beyond any we can apply in the puny and crude contrivances of our making? Is it not a fact that the suns and stars are under immense electrical pressures transcending any that man can ever produce and is this not equally true of the vacuum in celestial space? Finally, can there be any doubt that cosmic dust and meteoric matter present an infinitude of targets acting as reflectors and transformers of energy? If under ideal working conditions, and with apparatus on a scale beyond the grasp of the human mind, rays of surpassing intensity and penetrative power would not be generated, then, indeed, nature has made an unique exception to its laws.
"It has been suggested that the cosmic rays are electrons or that they are the result of creation of new matter in the interstellar deserts. These views are too fantastic to be even for a moment seriously considered. They are natural outcroppings of this age of deep but unrational thinking, of impossible theories, the latest of which might, perhaps, deal with the curvature of time. What this world of ours would be if time were curved…“
–Nikola Tesla
“The Eternal Source of Energy of the Universe, Origin and Intensity of Cosmic Rays.” October 13, 1932.
So, our physics teacher has the strange idea of motivating his students by letting each of us present a physical phenomenal we find interesting to our classmates in a 5-minutes-presentation. And now I need something that is interesting for everyone - even people that usually don't care for physics -, but has interesting facts for someone who's interested in it, too (preferably with an easy experiment). You don't happen to have any ideas, do you?
First of all, your professor is awesome for taking the time to do this. Of the top of my mind, the best one I have is Chladni figures.
Basically take a flat metal plate, fix it at the center and spray some fine sand particles on it.
Using a violin bow, gently excite any edge of the plate to magically witness these beautiful normal mode patterns ( known as Chladni patterns/figures ) forming on the plate.
Also notice that by pinching the plate at different points, the pattern obtained changes.
There is a whole lot of physics that goes behind such a simple phenomenon and I dare say we understand it completely. There are lots of questions on these figures that we have no answer for!
Hope this helps with your presentation. Have a good one!
Gif source video: Steve Mould
In slow motion, vortex rings can be truly stunning. This video shows two bubble rings underwater as they interact with one another. Upon approach, the two low-pressure vortex cores link up in what’s known as vortex reconnection. Note how the vortex rings split and reconnect in two places – not one. According to Helmholtz’s second theorem a vortex cannot end in a fluid–it must form a closed path (or end at a boundary); that’s why both sides come apart and together this way. After reconnection, waves ripple back and forth along the distorted vortex ring; these are known as Kelvin waves. Some of those perturbations bring two sides of the enlarged vortex ring too close to one another, causing a second vortex reconnection, which pinches off a smaller vortex ring. (Image source: A. Lawrence; submitted by Kam-Yung Soh)
Note: As with many viral images, locating a true source for this video is difficult. So far the closest to an original source I’ve found is the Instagram post linked above. If you know the original source, please let me know so that I can update the credit accordingly. Thanks!