Physics - Blog Posts
08.06.20
i made a whiteboard out of a poly pocket and it is, quite frankly, saving my ass with all the derivations i’m learning atm.
27th march 2020
was being all productive rewriting my higher physics notes (seeing as i’ve no set work until after easter -_-), but then i got onto fission and started raging about how undercredited lise meitner is, so now i’m in a state of feminist rage about the severe lack of women in stem and particularly physics. happy friday!
long time no see! last week i found out i’ve been accepted into the summer astrophysics programme i applied to which has made me so, so happy :D here’s to hard work paying off!
15-01-20
making some physics notes on onenote:) however i am becoming increasingly aware of and annoyed by the fact that our entire physics course is about men, there is not a single woman mentioned in the entire thing.
ninth of november, mmxix
some french speaking test prep and electricity revision qs 🇫🇷💡
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[ one hundred days of productivity: 3/100 ]
sun 18 august
powering through some physics revision while listening to ‘come from away’ before i retire for the night and watch some himym :)
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[4/50 days of productivity] 20 april
physics papers in the evening sun on our hideously green table. i absolutely love the warmth the uk’s getting at the moment, i spent most of today sitting in the sun with my friends- a calm before the storm of exams begins in under a week.
some pressure notes (i find it deeply amusing that there’s charles’ law and boyle’s law because of the character charles boyle in b99) (me and my friends often write each other notes on our books and recently our humour mostly involves brexit and theresa may- in retaliation to this i wrote brexit and drew a heart around it on her hand oops)
some voltage divider worked examples because they confused the hell out of me
Good vibrations no longer needed for speakers as research encourages graphene to talk
A pioneering new technique that encourages the wonder material graphene to “talk” could revolutionise the global audio and telecommunications industries.
Researchers from the University of Exeter have devised a ground-breaking method to use graphene to generate complex and controllable sound signals. In essence, it combines speaker, amplifier and graphic equaliser into a chip the size of a thumbnail.
Traditional speakers mechanically vibrate to produce sound, with a moving coil or membrane pushing the air around it back and forth. It is a bulky technology that has hardly changed in more than a century.
This innovative new technique involves no moving parts. A layer of the atomically thin material graphene is rapidly heated and cooled by an alternating electric current, and transfer of this thermal variation to the air causes it to expand and contract, thereby generating sound waves.
Read more.
Black phosphorus holds promise for the future of electronics
Discovered more than 100 years ago, black phosphorus was soon forgotten when there was no apparent use for it. In what may prove to be one of the great comeback stories of electrical engineering, it now stands to play a crucial role in the future of electronic and optoelectronic devices.
With a research team’s recent discovery, the material could possibly replace silicon as the primary material for electronics. The team’s research, led by Fengnian Xia, Yale’s Barton L. Weller Associate Professor in Engineering and Science, is published in the journal Nature Communications April 19.
With silicon as a semiconductor, the quest for ever-smaller electronic devices could soon reach its limit. With a thickness of just a few atomic layers, however, black phosphorus could usher in a new generation of smaller devices, flexible electronics, and faster transistors, say the researchers.
That’s due to two key properties. One is that black phosphorus has a higher mobility than silicon—that is, the speed at which it can carry an electrical charge. The other is that it has a bandgap, which gives a material the ability to act as a switch; it can turn on and off in the presence of an electric field and act as a semiconductor. Graphene, another material that has generated great interest in recent years, has a very high mobility, but it has no bandgap.
Read more.
Inspirational!
A schematic synthesis of physics branches by Dominic Walliman, from his video “The Map of Physics”:
Of course Physics become much more tangled when you move to the right side of the map.
h-t Vox: Physics has a dizzying array of subdisciplines. This short video breaks it down. An 8-minute history of the giant field of physics.
Walking into NASA wearing a ballgown and engineering a rocket
10/10 going to side-hustle as a lifestyle blogger and then when people call lifestyle bloggers ditzy or pull any other misogynistic “women can’t be interested in traditionally feminine things and traditionally smart at the same time” bullshit I’ll pull my physics degree out of a designer handbag and give them the middle finger
Circling the Sun (larger)
Alejandro Guijarro photographs the chalkboards of some of the brightest minds in quantum physics for his continuing series Momentum. He went to research facilities like CERN and many of the top universities in the world to find them.
Mythbusters Physics: Relative Velocity
The Mythbusters tested what would happen if a ball was shot at 60 mph off the back of a truck travelling at 60 mph to see what would happen.
It became a perfect example of the relative nature of physics - showing that velocity can vectorially add together. 60 mph in one direction cancels the 60 mph in the other, meaning a net velocity of zero.
RESONANCES! They affect everything!
Every 11 years, the Sun cycles through from riotous flare and sunspot activity to a quieter period, before ramping up again. It’s almost as regular as clockwork, and for years astronomers have been wondering what causes it. Now, they’ve proposed a new solution.
Even though the Solar System’s planets are much smaller than the Sun, the gravity of some of them is able to influence our star’s magnetic field. This, the researchers assert, is what controls the solar cycle.
Venus, Earth, and Jupiter assert a small gravitational tug on the Sun as they orbit it. The result is comparable to the way the Moon’s gravity influences Earth’s tides, producing a regularly timed ebb and flow.
The team has traced back 1,000 years of solar cycles, between the years 1000 and 2009 CE, comparing that data against the movements of the planets in that time. They found an impressively strong link between the two.
“There is an astonishingly high level of concordance: what we see is complete parallelism with the planets over the course of 90 cycles,” said physicist Frank Stefani of the Helmholtz-Zentrum Dresden-Rossendorf in Germany.
“Everything points to a clocked process.”
What the team found is that the tidal forces are strongest when Earth, Venus, and Jupiter align, and that this alignment occurs every 11.07 years - falling at the same time as the solar minimum.
Continue Reading.
In a recent video, Practical Engineering tackles an important and often-overlooked challenge in civil engineering: dam failure. At its simplest, a levee or dam is a wall built to hold back water, and the higher that water is, the greater the pressure at its base. That pressure can drive water to seep between the grains of soil beneath the dam. As you can see in the demo below, seeping water can take a curving path through the soil beneath a dam in order to get to the other side. When too much water makes it into the soil, it pushes grains apart and makes them slip easily; this is known as liquefaction. As the name suggests, the sediment begins behaving like a fluid, quickly leading to a complete failure of the dam as its foundation flows away. With older infrastructure and increased flooding from extreme weather events, this is a serious problem facing many communities. (Video and image credit: Practical Engineering)
Black Holes are not so Black (Part 3) - Gravitational Waves
The existence of Gravitational Waves have been confirmed. But you probably have heard that. In this post, we will break down this profound discovery into comprehend-able chunks.
This is going to be a amazing journey. Ready ?
Redefining Gravity
When we usually talk of Gravitation we are bound to think like Newton, where objects are assumed to exerting a force upon each other.
Like imaginary arrows of force in space. But this picture, although good for high school crumbled, with the advent of Einstein’s theory of Relativity.
What is the Space-Time Fabric?
Think of space-time fabric as an actual cloth of fabric. ( An analogy )
When you place an object on the fabric, the cloth curves. This is exactly what happens in the solar system as well.
The sun with such a huge mass bends the space-time fabric. And the earth and all the planets are kept in orbit by following this curvature that has been made by the sun.
Attributing to the various masses of objects, the way they bend this fabric also varies.
What are Gravitational Waves?
If you drop an object in a medium such as water, they produce ripples that propagate as waves through the medium.
Similarly, Gravitational waves are ripples in space-time fabric produced when you drag heavy objects through space time.
And the nature of these waves is that they don’t require a medium to propagate.
How do you make one?
Everything with mass/energy can create these waves.
Source
Two persons dancing around each other in space too can create gravitational waves. But the waves would be extremely faint.
You need something big and massive accelerating through space-time in order to even detect them.
And orbiting binary stars/black holes are valuable in this retrospect.
How can you detect them?
Let’s turn to the problem to detecting them assuming you do find binary stars/black-holes in the wondrous space to suite your needs.
Well, for starters you cannot use rocks/ rulers to measure them because as the space expands and contracts, so do the rocks. ( the distances will remain same in both the cases )
Here’s where the high school fact that the speed of Light is a constant no matter what plays an important and pivotal role.
If the space expands, the time taken for light to reach from A to B would be longer. And if it contracts, the time taken for it to reach from A to B would be smaller.
PC: PHDComics
By allowing the light waves from the contraction and expansion to interfere with each other, such as done in any interferometry experiment we can detect the expansion or contraction. Voila!
And this is exactly what they did! ( on a macroscopic level ) at LIGO (Laser Interferometer Gravitational-Wave Observatory)
14 September 2015
Two Black Holes with masses of 29 and 36 solar masses merged together some 1.3 Billion light years away.
Two Black Holes colliding is the header animation of the ‘Black Holes are not so Black Series’, in case if you haven’t noticed.
The merger of these two black holes results in the emission of energy equivalent to 3 solar masses as Gravitational Waves.
This signal was seen by both LIGO detectors, in Livingston and Hanford, with a time difference of 7 milliseconds.
And with the measurement of this time difference, physicists have pronounced the existence of Gravitational Waves.
Source
All this is most certainly easily said than done and requires meticulous and extensive research, not to mention highly sensitive instruments.
Had they not have measured this time difference, we might have had to wait for the merger for more massive black holes to collide and maybe even build more sensitive instruments to detect these waves.
And Einstein predicted this a 100 years back!
Mind Blown!
Note: Hope you are able to understand and appreciate the profundity of the discovery done by mankind.
** All animations used here are merely for Educational purposes. If you have any issues, please write to us at : 153armstrong@gmail.com
Top 10 Most Uncomfortable Physics Facts
While physics can show us amazing things about our universe, it doesn’t always agree with how we think things should work. Sometimes, physics can be very counter-intuitive, and often unsettling. So, here’s my list of physics facts that can be a bit unnerving.
10: Weight doesn’t matter
If it wasn’t for air resistance, everything would fall at exactly the same speed. If you let go of a hammer and a feather from the same height at the same time on the Moon, they would hit the ground simultaneously.
9: Gyroscopic precession
It doesn’t matter how much you know about physics; gyroscopes are weird. The way they seem to defy gravity makes you rethink everything you know about physics, despite being fairly simple toys. Still, it’s all just Newton’s laws of motion.
8: Neutrinos and dark matter
We like to think that we can interact with most of the world around us, but this couldn’t be further from the truth. Neutrinos and dark matter are passing through your body right now, as if you weren’t even there. The fact that 65 billion neutrinos pass through each square centimeter of your body every second is weird enough, who knows what we’ll learn about dark matter.
7: Photons are particles
Light travels like a wave, but can only interact like a particle. It can interfere and have a frequency, but it can only take and give energy in discrete quantities. It behaves like nothing else in our macroscopic world, and can be very difficult to imagine.
6: Electrons are waves
We’ve established how photons act like waves and particles, but surely massive particles act normally. Nope! Even electrons have wave-like properties. In fact, everything acts like a wave! Except these waves come in discrete quantities, which we’ll call particles. This won’t get confusing.
5: E=mc^2
Einstein’s most famous contribution to physics states that matter is simply another form of energy, which has very profound consequences. A wound-up Jack-in-a-box would weigh ever so slightly more than a released Jack-in-a-box, due to the potential energy stored within.
4: Time is relative
The core of special relativity states that time passes differently for different observers. If you took a trip to Alpha Centauri at 99% the speed of light, everyone on Earth would see the trip take 4.4 years, while you would only experience 7.5 months. Time travel is real!
3: The (not so empty) vacuum
Something can be created from nothing, as long as it goes right back to being nothing quickly. In seemingly empty space, particles pop in and out of existence all the time as a result of the uncertainty principle. Not to mention, space is inflating at an accelerated rate due to “dark energy”. To the vacuum, the law of conservation of energy is more of a suggestion.
2: c is the fastest speed
Another important point in special relativity is that nothing could ever go faster than light. This doesn’t sit well with a lot of people, but the math doesn’t lie. To even get something with mass to travel at the speed of light would require infinite energy. Even if you somehow get around this, there are just too many mathematical problems with superluminal travel. Like it or not, the universe has a speed limit.
1: The cat is dead and alive
How could it not be this? The nature of quantum mechanics allows for objects to take on two seemingly contradictory states in a ‘superposition’. An electron can be in two places at once, or in a more extreme example, a cat can be both dead and alive. Of course, this weird property goes away once someone makes an observation. It’s as if there are tiny physics trolls messing with nature whenever we’re not looking.
Of course, there’s plenty more unsettling physics facts, like the space-bending nature of general relativity, or the “spooky action at a distance” that is quantum entanglement, but these are my top 10. I’d like to hear any unsettling physics facts you think I’ve missed, though!
It’s easy: Form a triangle, then a hexagon, then a bicycle wheel
This is the general mechanism on how a spider spins its web (talk about engineering, right?). When an insect gets caught in its web, the vibrations caused by the insect is felt by the spider which then rushes to engulf its prey.
Now here is the trippy part ; This is the effect of drugs on the pattern of the web.
Hope you are having a great week. Have a good one!
* Spider spinning a web (video) (if you find a better full video let us know)
** Spiders on drugs - NASA article ; Video
Superfluid Helium
It was previously thought that superfluid Helium would flow continuously without losing kinetic energy. Mathematicians at Newcastle University demonstrated that this is only the case on a surface completely smooth down to the scale of nanometers; and no surface is that smooth.
When a regular fluid like water is passing over a surface, friction creates a boundary layer that ‘sticks’ to surfaces. Just like a regular fluid, when superfluid Helium passes over a rough surface there is a boundary layer created. However the cause is very different. As superfluid Helium flows past a rough surface, mini tornados are created which tangle up and stick together creating a slow-moving boundary layer between the free-moving fluid and the surface. This lack of viscosity is one of the key features that define what a superfluid is and now we know why it still loses kinetic energy when passing over a rough surface.
Now we can use this information to help our efforts on applications of superfluids in precision measurement devices such as gyroscopes (I think this was on the Big Bang theory where they make a gyroscope using superfluid Helium that can maintain angular momentum indefinitely because it would flow across a smooth surface without losing kinetic energy) and as coolants.
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!
Harmonograph, H. Irwine Whitty, 1893
“The facts that musical notes are due to regular air-pulses, and that the pitch of the note depends on the frequency with which these pulses succeed each other, are too well known to require any extended notice. But although these phenomena and their laws have been known for a very long time, Chladni, late in the last century, was the first who discovered that there was a connection between sound and form.”
source here
Once Upon a Time t
Once upon the time t(0) there was a young buck named Butterbean who wanted nothing more than to know his ontological value. Being familiar with the concepts of quantum mechanics he was sadly aware that this was theoretically impossible, but remained unsatisfied with the notion.
In an undying effort to discover the nature of his own existence he set out on a journey to seek the answer from all those most wise and perceiving.
Clearly the first stop was at the front door of Glad the hippopotamus.
Glad was of the notion that all things are ultimately mundane and that it is simply a matter of time and “progress” before esoteric conundrums become simple everyday knowledge. Surely this most assured creature could derive an unknown variable to discover the true nature of Butterbean himself. They were both of the mind at this time t(realist) that all the probabilistic nonsense was clearly just a cop out for those ninnies who fancied themselves finished with discovering the universe.
Alas after decades, or maybe days (no one can be sure given that time itself is a construct commonly defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom, and who can really say cesium 133 even exists… really), Glad was forced to admit that he could not tell Butterbean of his ontological state prior to Butterbean’s arrival on his doorstep, nor could he possibly without any reference to his own experience as a literalist hippo, and was forced to admit that this coveted obscure variable was beyond his abilities of perception.
With a sense of hopelessness Butterbean sought out the comfort and guidance of Ol’ Trusty, the Wire Stripper. They adventured together for t(hedonist) to t(fundamentalist) without ever committing to any defined notion as after all, how can you find the answer to a paradox, oxymoron much?
However comfort in ignorance becomes unsettling after you’ve had your fun and Butterbean became restless. There was one more known avenue he had not yet travelled…
With a renewed sense of wonder and determination Butterbean approached the Oak, which shook its branches excitedly upon Butterbean’s arrival to see such a valiant seeker of answers. “Oak, what can you tell me about my ontological value?” asked Butterbean humbly. The Oak remained silent, but a slight breeze rustled loose a few leaves from its massive head which fluttered to the ground and landed lightly at Butterbean’s feet, Butterbean faltered and then turned and retreated thoughtfully sensing that the conversation was over.
Upon further consideration over Δt(orthodox) Butterbean understood Oak’s lesson— the leaves could change position through many methods all resulting in different outcomes, however before any leaf falls, it has not fallen. Butterbean had discovered that no matter who or what observes him, there would be an outcome, but it could not be these interactions which defined the whole of himself, surely he must be something inherently like the leaves of Oak’s mane.
One day, a little time later at approximately t(decision), Butterbean decided to venture forth in search of a method of measurement that excluded observation. Knowing that the existence of alligators had long been debated among those with a higher understanding of the nature of things, he knew he should seek within the mind of that which may or may not exist; namely an alligator (though a unicorn or manticore could have sufficed, they are not quite as easy to find nowadays).
Unfortunately all alligators are actually just dead trees and Butterbean had to once again rethink his strategy.
It occurred to Butterbean, after his most recent experiences, that perhaps his disbelief in alligators had caused their value to be null, distracted in hoping that his mind was not quite that powerful Butterbean mistakenly stomped on a daisy which let out a loud squeal, “watch out dummy!” “OH!” replied Butterbean, “Sorry I didn’t see you there, though come to think of it I’m surprised you even exist as I hadn’t yet observed you my friend.” The daisy straightened herself and smoothing out her petals scoffed and said jeeringly, “you think that you are the only one who exists, eh?” “Well,” began Butterbean thoughtfully, “no, but I don’t understand how anything or anyone has any sort of defined nature without something else purposefully interacting with it, after all, how do you know that you exist?” “Oh for goodness sake,” exclaimed young Daisy, “Of course you’ll remain limited as long as you keep collapsing your wave function with all that introspection!” And she turned her face to the sun clearly dismissing Butterbean and all his angsty questions.
Butterbean, with all known theories exhausted, was still unsatisfied and longed to know the mystery of his own nature of being and the recent dismissal of the daisy weighed heavy on his soul. “Why can she be so satisfied just being,” he wondered, “when I spend all of my time dedicated to the mystery and nature of life but still feel so empty and unfulfilled?” And suddenly it struck him! It had been so obvious all along and basically verbatim the retorts he had only just received from the annoyed flower he had trod on, Butterbean ceased to observe himself and existed infinitely in all possible states of being.
