Physics - Blog Posts
i said 'explain physics to me like youre in love with me' and after a while of quiet he went 'everything sings'. so i get it now
"Decrease the increase" is actually a completely reasonable thing to say, but it feels like it shouldn't be.
Getting stuff from DR to CR (Interesting interview)
Yes, it is possible. I saw an interview with a shifter who has been shifting for tens of thousands of years on Amino. In his interview, he said that he tried to bring objects from other realities into this reality. He would concentrate and think that he had the object he remembered in this reality, and the object he had in mind would appear in his hand.
However, there were some limitations, such as not being able to bring objects back exactly the same. For example, objects created in worlds with incompatible physics would have a similar appearance, but the function or behavior of the object would change to fit this reality.
I have also seen several shifters experiment with bringing objects back, some with failure, some with success.
You can find an interview on this interesting topic here:
Quantum physics has proven that the universe is not locally real and without consciousness the 3D doesn't exist. So how can 3D be considered a reality?
Anyone can help me with Physics topic 'Earth's Magnetic Field' please 😭😭
I'm stucked with my assignment. Please help me.
Physics light academia moodboard for @chazza-studies-alevels enjoy! ☺️💫
Send me a request for a moodboard or playlist
Day 44/100 days of productivity
Achievements:
Finished writing the first draft of my language project
Annotated some of my research sources
Set up a new morning routine
Read 4 chapters of my book
Started reading “the miracle morning”
Had an alright day today, feeling a lot better recently ☺️
it’s all I ever wanted to be
Working The Night Shift
People think I'm lazy
But I'm awake for the same amount of time they are
I am just awake and asleep at a different time
They see me sleeping all day
But that’s because I'm awake all night
They say the early bird gets the worm
But what if I happen to consider myself the worm?
Not only that but…
The second mouse gets the cheese
I'm nocturnal
Either that or I was meant for the other side of the planet
But I do like seeing the stars
Street lights and few cars
It’s nice to be unbothered
By anyone really
Daytime people
Won’t understand the mood
Of Ziggy Stardust or the Dark Side of the Moon
Only Spacetime Oddities
Know about the secret societies
That only meet in the night,
Only to mess with the forces
Of the good, the bad, and the gravity
Along with pronking springboks
Physics Dynamics Assignment
November 25-30, 2022
Gr12 physics video I had to make. I carried so hard for this bro.
Just a bunch of yapping.
There's smth we calculated wrong but idc enough to check
#TodayinSTEM: Albert Einstein was awarded the Benjamin Franklin Medal for his contributions to theoretical #physics in 1935.
This makes me sound stupid but what does a feynman diagram mean?
You don’t sound stupid! They can be pretty confusing at first, and I’m sure you’re not they only one that doesn’t fully understand them (myself included) so let’s learn how to draw Feynman diagrams!
You do not need to know any fancy-schmancy math or physics to do this!
I know a lot of people are intimidated by physics: don’t be! Today there will be no equations, just non-threatening squiggly lines. Even school children can learn how to draw Feynman diagrams. Particle physics: fun for the whole family.
For now, think of this as a game. You’ll need a piece of paper and a pen/pencil. The rules are as follows (read these carefully):
1. You can draw two kinds of lines, a straight line with an arrow or a wiggly line:
You can draw these pointing in any direction.
2. You may only connect these lines if you have two lines with arrows meeting a single wiggly line.
Note that the orientation of the arrows is important! You must have exactly one arrow going into the vertex and exactly one arrow coming out.
3. Your diagram should only contain connected pieces. That is every line must connect to at least one vertex. There shouldn’t be any disconnected part of the diagram.
In the image above, the diagram on the left is allowed while the one on the right is not since the top and bottom parts don’t connect.
4. What’s really important are the endpoints of each line, so we can get rid of excess curves. You should treat each line as a shoelace and pull each line taut to make them nice and neat. They should be as straight as possible. (But the wiggly line stays wiggly!)
That’s it! Those are the rules of the game. Any diagram you can draw that passes these rules is a valid Feynman diagram. We will call this game QED. Take some time now to draw a few diagrams. Beware of a few common pitfalls of diagrams that do not work (can you see why?):
After a while, you might notice a few patterns emerging. For example, you could count the number of external lines (one free end) versus the number of internal lines (both ends attached to a vertex).
How are the number of external lines related to the number of internal lines and vertices?
If I tell you the number of external lines with arrows point inward, can you tell me the number of external lines with arrows pointing outward? Does a similar relation hole for the number of external wiggly lines?
If you keep following the arrowed lines, is it possible to end on some internal vertex?
Did you consider diagrams that contain closed loops? If not, do your answers to the above two questions change?
I won’t answer these questions for you, at least not in this post. Take some time to really play with these diagrams. There’s a lot of intuition you can develop with this “QED” game. After a while, you’ll have a pleasantly silly-looking piece of paper and you’ll be ready to move on to the next discussion:
What does it all mean?
Now we get to some physics. Each line in rule (1) is called a particle. (Aha!) The vertex in rule (2) is called an interaction. The rules above are an outline for a theory of particles and their interactions. We called it QED, which is short for quantum electrodynamics. The lines with arrows are matter particles (“fermions”). The wiggly line is a force particle (“boson”) which, in this case, mediates electromagnetic interactions: it is the photon.
The diagrams tell a story about how a set of particles interact. We read the diagrams from left to right, so if you have up-and-down lines you should shift them a little so they slant in either direction. This left-to-right reading is important since it determines our interpretation of the diagrams. Matter particles with arrows pointing from left to right are electrons. Matter particles with arrows pointing in the other direction are positrons (antimatter!). In fact, you can think about the arrow as pointing in the direction of the flow of electric charge. As a summary, we our particle content is:
(e+ is a positron, e- is an electron, and the gamma is a photon… think of a gamma ray.)
From this we can make a few important remarks:
The interaction with a photon shown above secretly includes information about the conservation of electric charge: for every arrow coming in, there must be an arrow coming out.
But wait: we can also rotate the interaction so that it tells a different story. Here are a few examples of the different ways one can interpret the single interaction (reading from left to right):
These are to be interpreted as: (1) an electron emits a photon and keeps going, (2) a positron absorbs a photon and keeps going, (3) an electron and positron annihilate into a photon, (4) a photon spontaneously “pair produces” an electron and positron.
On the left side of a diagram we have “incoming particles,” these are the particles that are about to crash into each other to do something interesting. For example, at the LHC these ‘incoming particles’ are the quarks and gluons that live inside the accelerated protons. On the right side of a diagram we have “outgoing particles,” these are the things which are detected after an interesting interaction.
For the theory above, we can imagine an electron/positron collider like the the old LEP and SLAC facilities. In these experiments an electron and positron collide and the resulting outgoing particles are detected. In our simple QED theory, what kinds of “experimental signatures” (outgoing particle configurations) could they measure? (e.g. is it possible to have a signature of a single electron with two positrons? Are there constraints on how many photons come out?)
So we see that the external lines correspond to incoming or outgoing particles. What about the internal lines? These represent virtual particles that are never directly observed. They are created quantum mechanically and disappear quantum mechanically, serving only the purpose of allowing a given set of interactions to occur to allow the incoming particles to turn into the outgoing particles. We’ll have a lot to say about these guys in future posts. Here’s an example where we have a virtual photon mediating the interaction between an electron and a positron.
In the first diagram the electron and positron annihilate into a photon which then produces another electron-positron pair. In the second diagram an electron tosses a photon to a nearby positron (without ever touching the positron). This all meshes with the idea that force particles are just weird quantum objects which mediate forces. However, our theory treats force and matter particles on equal footing. We could draw diagrams where there are photons in the external state and electrons are virtual:
This is a process where light (the photon) and an electron bounce off each other and is called Compton scattering. Note, by the way, that I didn’t bother to slant the vertical virtual particle in the second diagram. This is because it doesn’t matter whether we interpret it as a virtual electron or a virtual positron: we can either say (1) that the electron emits a photon and then scatters off of the incoming photon, or (2) we can say that the incoming photon pair produced with the resulting positron annihilating with the electron to form an outgoing photon:
Anyway, this is the basic idea of Feynman diagrams. They allow us to write down what interactions are possible. However, you will eventually discover that there is a much more mathematical interpretation of these diagrams that produces the mathematical expressions that predict the probability of these interactions to occur, and so there is actually some rather complicated mathematics “under the hood.” But just like a work of art, it’s perfectly acceptable to appreciate these diagrams at face value as diagrams of particle interactions. Let me close with a quick “frequently asked questions”:
What is the significance of the x and y axes?These are really spacetime diagrams that outline the “trajectory” of particles. By reading these diagrams from left to right, we interpret the x axis as time. You can think of each vertical slice as a moment in time. The y axis is roughly the space direction.
So are you telling me that the particles travel in straight lines?No, but it’s easy to mistakenly believe this if you take the diagrams too seriously. The path that particles take through actual space is determined not only by the interactions (which are captured by Feynman diagrams), but the kinematics (which is not). For example, one would still have to impose things like momentum and energy conservation. The point of the Feynman diagram is to understand the interactions along a particle’s path, not the actual trajectory of the particle in space.
Does this mean that positrons are just electrons moving backwards in time?In the early days of quantum electrodynamics this seemed to be an idea that people liked to say once in a while because it sounds neat. Diagrammatically (and in some sense mathematically) one can take this interpretation, but it doesn’t really buy you anything. Among other more technical reasons, this viewpoint is rather counterproductive because the mathematical framework of quantum field theory is built upon the idea of causality.
What does it mean that a set of incoming particles and outgoing particles can have multiple diagrams?In the examples above of two-to-two scattering I showed two different diagrams that take the in-state and produce the required out-state. In fact, there are an infinite set of such diagrams. (Can you draw a few more?) Quantum mechanically, one has to sum over all the different ways to get from the in state to the out state. This should sound familiar: it’s just the usual sum over paths in the double slit experiment that we discussed before. We’ll have plenty more to say about this, but the idea is that one has to add the mathematical expressions associated with each diagram just like we had to sum numbers associated with each path in the double slit experiment.
What is the significance of rules 3 and 4?Rule 3 says that we’re only going to care about one particular chain of interactions. We don’t care about additional particles which don’t interact or additional independent chains of interactions. Rule 4 just makes the diagrams easier to read. Occasionally we’ll have to draw curvy lines or even lines that “slide under” other lines.
Where do the rules come from?The rules that we gave above (called Feynman rules) are essentially the definition of a theory of particle physics. More completely, the rules should also include a few numbers associated with the parameters of the theory (e.g. the masses of the particles, how strongly they couple), but we won’t worry about these. Graduate students in particle physics spent much of their first year learning how to carefully extract the diagrammatic rules from mathematical expressions (and then how to use the diagrams to do more math), but the physical content of the theory is most intuitively understood by looking at the diagrams directly and ignoring the math. If you’re really curious, the expression from which one obtains the rules looks something like this (from TD Gutierrez), though that’s a deliberately “scary-looking” formulation.
You’ll develop more intuition about these diagrams and eventually get to some LHC physics, but hopefully this will get the ball rolling for you.
Notes taken during Physics lessons! Exams end in 5 days and I can’t wait!!!!!!
Do you think the “Observer Effect” also works on the electrons in our body
& that’s why we can feel when we’re being watched?
‘If moon was just any place‘
Chain Reaction.
Everyone knows that a line of standing dominos creates a fun chain reaction when you knock the first one over; but did you know you can use increasingly larger dominos and get the same result?
The setup.
Professor Stephen Morris knocks over a 1-meter tall domino that weighs over 100 pounds by starting with a 5mm high by 1mm thick domino.He uses a size ratio of 1.5, meaning each domino is one and a half times larger than the last one. This is the generally accepted maximum ratio that dominos can have to successfully knock each other over.
Hans Van Leeuwen of Leiden University in the Netherlands, published a paper online showing that, theoretically, you could have a size ratio of up to two. But that’s in an ideal (and probably unrealistic) situation.
Fun fact.
There are 13 dominoes in this sequence. If Professor Morris used 29 dominoes in total, with the next one always being 1.5x larger, the last domino would be the height of the Empire State Building.
Source: Physics Buzz.
Major types of Engines
Straight In-line
This is the type of engine that you find in your quotidian car. Nothing fancy, just all pistons arranged parallel along the vertical direction.
V in-line
Now, this is the sort of the engine that you find on sports cars like the Ferrari. When you hear sports enthusiasts go ‘ Whoa, that’s a V-12! ‘ - it just means that the engine has a V-type arrangement with 12 cylinders.
V + Inline = V-inline
Commonly referred to as the VR engine.
The name VR6 comes from a combination of V engine (German: V-Motor), and the German word “Reihenmotor” (meaning “inline engine” or “straight engine”)
Volkswagen’s VR6 engines, and the later VR5 variants, are a family of internal combustion engines, characterized by a narrow-angle (10.5° or 15°) V engine configuration.
a: straight engine, b: V engine, c: VR engine
W engine
A W engine is a type of reciprocating engine ( again created by Volkswagen) arranged with its cylinders in a configuration in which the cylinder banks resemble the letter W, in the same way those of a V engine resemble the letter V.
A W16 engine is used on the Bugatti Veyron. That’s 16 cylinders!
Flat Engine
Flat engines offer several advantages for motorcycles, namely: a low centre of gravity, smoothness, suitability for shaft drive, and (if air-cooled) excellent cooling of the cylinders. You can find them on aircrafts as well
Radial Engine (aka the dancing starfish)
They were used mostly in small aircraft for the propeller
The big advantage of radials was their large frontal area, which meant they could be air cooled, meaning less maintenance, failures, and of course a lower cost of initial purchase and maintenance.
Wankel Engine
This engine has only 3 moving parts and can make a lot of power.However, they are pretty inefficient, the last car to use this was a Mazda RX-8.
Axial Engine
The axial engine is a very interesting design. But they are not widely used because they are just hard to make and running these things at high RPM’s is a challenge.
Duke engines are equipped with this type.
Jet engine
Commonly jet engines refer to the engines that are found on, well Jets!
Air is sucked in through the front and squeezed. A controlled explosion follows and the exhaust is blown out through the back
But, Jet engines also include the engines that are found on rockets, hybrids and water-jets. And their mode of operation is different than the one mentioned above.
Pretty cool eh?
Have a great day!
PC: Howstuffworks, Duke, MichaelFrey, Azure.km
** There is also the Stirling Engine. It’s amazing and a topic for an another post. But if you are interested do check out more about it here.
EDIT : Had forgotten about the VR and the W-engines. My bad! Thanks for pointing it out.:D
What is Brightness?
There has always been this nudge,right. The nudge to know what IS brightness. The subtle divergence between what we perceive as dim and bright. What it really means!
The brilliance of the sun whose light emerges afar blinds us but yet the quotidian florescent light seems to oblivious to us. Why this madness ! It doesn’t make sense to me.
Light as a particle
Two light bulbs 100W and 20W respectively. It is obvious that the 100 W glows brighter than its counterpart.
This is so because each photon ( a particle ) carries with it an amount of energy proportional to its frequency; E=hν. The energy dissipated per unit area is the energy per photon times the photons per unit area per second.
The 100 W bulb emits more photons per second than the 20 W bulb.
In this model, the photoreceptors in your eye undergo chemical reactions as a result of absorbing photons. The more photons absorbed per second, the brighter the light appears.
Light as a wave
In the picture of light as an electromagnetic wave, the energy carried by the light is proportional to the square of the wave’s amplitude.
In this model, the photo-receptors in your eye are oscillators. What is oscillating? Electric charge.
Charges are accelerated in response to the electric field of the light: the greater the electric field (or amplitude), the greater the amplitude of the oscillation, and the greater the electric currents in your eye (and the greater the brightness).
The human eye is truly a marvel. The level of serenity it brings to life is just enthralling.Have a great day!
- Post adapted from this stackexchange.
11/09/20
physics <3
02/09/20
one of those days where my brain feels completely fried by hometime.
25/08/20
adulting is difficult, folks. but also kind of exciting sometimes?
24/08/20
gravitation notes!
07/08/20
coded a rock, paper, scissors game! (=> completed one of my summer goals!)
did some mini exercises and summary post-it’s of rotational motion
read a third of the good immigrant
& tonight i’m going cycling with my dad and will do another violin session!
summer studying challenge, 7th aug: what is your favourite summer ‘beach read’?
red, white & royal blue by casey mcquiston!