I’m a high school student who wants to pursue a PhD in physics in the future. But right now, when I face reality, I realize that I just cram all the high school physics material. In about 6–7 months, I’ll be starting college. At the same time, I’m also trying to convince my parents to give me the freedom to choose my own undergraduate path. They want me to study engineering or medicine, but I am planning for a PhD, which I know is very difficult and one of the hardest paths for an average person.

My real concern is: do I have to memorize every single line of the physics textbook? After exams, I tend to forget everything within a few days. Then I revise the concepts again, but the cycle goes on forever. I’m worried that I might not be able to make it in college.

After all this, my heart still sticks with physics. Is there any solution? Or will I have to learn all the high school material again before starting college?

This is probably a really dumb question, but I was thinking about it while at work. If you existed in a 2D space, you would only need a bipod, however in 3D it needs 3 legs to actually be stable. Is this proportional - e.g. 4D = 4 legs etc.?

I’m taking physics 1 this fall and have read online that knowing calculus makes it easier.

I took calculus 1 about 5 years ago but I barely remember anything now. Now I’m debating whether I should give myself a crash course on calculus 1 to myself by binge watching courses on YouTube.

Any advice would be appreciated!

How thick is the disc?

Cars like the Porsche gt3rs, Honda NSX (1st gen), z06 & z07 Corvette which have mid engine layouts effortlessly go around corners at high speeds without needing to brake much at all.

Hi, i am doing a project of stress testing materials. I made two molds, one with ECOFLEX having a 10 x 10 mm area and 3 mm thickness, and one with same dimensions but with the addition of iron fillings. I then applied a gradual compressive force from 0 - 20 N on both and at 20 N the ECOFLEX was compresses to about 1.5 mm while the one with iron fillings was compresses to about 2 mm. In my mind the one with the iron filling one should be not be compressed as much. I couldn't get any supporting document as why is that. my question is it compressing more that a literal silicon? i did multiple tests and got the same results.

I’m curious to hear fun, weird, or surprising physics facts.

This might be an unconventional question, but I am finishing my PhD in atomic physics this fall. I plan to get a physics inspired tattoo, and this got me to wonder if there's a nice concise list of "drawings" or diagrams that people have made of atomic theory through the ages?

There's the classic diagrams of models, like that of Rutherford, Bohr, etc. But are there any diagrams that Democritus drew?

Edit: for sake of crossing my i's and dotting my t's I should say, I fully understand that the theory of atomomism in Greek philosophy was a far way from any recent understanding.

from what ive been told (and ofc this could be wrong) if you double the energy you put into something, it wont double its velocity, but rather it will increase by a factor of ~1.41. but...

imagine a rocket and masses y, and z.

rocket, y and z are all stationary relative to each other. we then burn, say 1 liter of some arbitrary fuel in the rocket. now its going 1 MPS relative to y and z. from what i understand, if we burn another liter, assuming no drag perfect efficiency etc, itl just be going 1.41 MPS. but...

imagine we speed up y to 1 MPS in the same direction. so now rocket is moving at 0MPS relative to y, and 1 relative to z. we then burn another liter of fuel. since burning a liter of fuel took the rocket from 0 to 1 mps when it was relative to y and y, should it not do the same to it relative to Z, and thus 2 MPS relative to y?

the only explanation i can think of is that the fuel itself has more energy, as it too is moving relative to the y

sorry if this is hard to follow i feel i couldve worded it better but im tired lol

In order to maintain the rotational motion at constant angular velocity, an additional co-planar force Fy is suggested to be applied onto the rod. Determine:

What that mean by applied onto the road

are susskind books good enough to self learn physics or is there anything else youd recommand me getting?

He didn’t make contact with the ball. To my knowledge this has never happened before. Is it just about the change in velocity of him stopping the swing? Was there likely something wrong with the bat?

Why can’t we perceive a 4th dimension, or a 5th dimension? Is it just because we only live in a 3rd dimensional space?

Hi I want to learn more about physics. My understanding currently is probably quite basic compared to what I think it is . So I thought watching some YouTube channels might help ? Are there any that might have a more “lively” voice because a lot of them have quite monotone voices.(not to be rude just I learn a lot more from channels with more “lively” voices.

I apologize if the answer to this question is obvious, but this was a shower thought so it’s real physics initially and then gibberish.

My understanding is that one of the reasons we observe spatial translation invariance (if I even understand that correctly) throughout the universe is because it is flat. Please correct any of this so I have a more precise understanding.

Gibberish:

The rest of this may be irrelevant if the answer is no.

If the universe is infinite, can it be curved? If so, would it ever curve back in on itself?

Also, if conditions somehow did change somewhere else unimaginably vast distances away from us, would we ever be able to observe that, even with wormhole tech? Would it even be possible for us to ever detect curvature of an infinite universe, or would it even have real measurable curvature at all?

Thanks in advance if you choose to entertain the last part!

Hey! So I was wondering if y'all could help clear up my confusion. Basically, I asked deepseek (chinese chatgpt, uses way less energy though) what I should do to keep my room cool and it suggested cheap DIY window covers.

Basically, I live in a hot inland area and so it said "get a piece of thick corrugated cardboard, paint ONE side white, cover the OTHER side with aluminum foil, glue some BOTTLE CAPS onto the foil side, and finally: DUCT TAPE the bottle caps onto the OUTSIDE of your windows.

Basically, I /understand/ how white paint reflects sunlight.....but it said to use foil and an air gap because supposedly "the gap in between the cardboard will PREVENT heat from transferring.....and the foil will help radiate back OUTWARD".......but is this TRUE? Please help me out, I'm just tired of feeling like I'm in a life-sized air fryer lol.

Hey everybody, I have a practical physics problem that I'm having trouble wrapping my head around.

I love gin and tonics, but I'm constantly running into the problem of my tonic water losing carbonation due to the fact that I buy it in either 1 or 2 liter plastic bottles (yes, I recycle them religiously. Even before you start. ;-) ). Convenient, except for the fact that no matter how much you tighten the cap, it goes flat quickly. So I had the idea of storing the bottle upside down in the fridge. My hypothesis is that even though CO2 doesn't rise, the reason why it releases when you open something carbonated is because of the super-saturation in the water, so storing it upside down *should* keep it from leaking out of the cap because it has a plastic barrier on top and a water barrier below.

Am I wrong here? I feel like I'm missing something. Like maybe the CO2 will release just as quickly from the water regardless of the bottle's positioning because the water is already super-saturated, so it isn't really an effective barrier.

Anyway, thanks for your help in advance.

Hello again physics reddit, I am once again begging for some guidance as I go about writing in the POV of a character who is much smarter than I am :)

I am humbling coming to you all with two lines of questioning today.

1. Are there certain equations or concepts you find yourself applying to different aspects of life, or just thinking about a lot in general because they're interesting? Are there any formulas you personally find beautiful?

My character has shown a great affinity for math from a young age, and became interested in physics as a young teen. He received a great education, and did a lot of self-study, but his life was derailed after just two years in undergrad.

I am trying to find a balance between 'how this character's mind processes the world' without long paragraphs of math-dumping in the narrative.

2. What part does Probability play in the world of physics?

There is a point in the story where probabilities come into play. And I know this character would have studied probability at some point in his education, but whether or not this is a topic he would have spent a lot of time in (and so would have no issue) or just passed through (and would maybe struggle just a tad more), I really have no idea.

Hey y'all, not sure if I'm in the right place, but hoping someone here might be willing to help a dad out.

My son (14, on the spectrum) recently watched the Chernobyl miniseries and now he's obsessed with radiation. I bought him a digital Geiger counter last spring, but we quickly realized we didn't have anything radioactive enough to set it off. Bought some various substances and items (autunite sealed in plastic, uranium glass slag, Fiestaware, Geiger counter test card, etc) but he's dead-set on getting hotter and hotter stuff.

Hottest thing we've got right now is the Fiestaware, which tops out around 5.5K cpm. He's got his eye on a vintage Kodak thoriated lens (thorium-232) from geigercheck.com that (per the website) emits around 22K cpm. My (very rudimentary) understanding is that most of the radiation from thorium should be alpha particles, but that gamma rays will creep into the mix as the nuclei decay.

Currently he's keeping all his (small) samples in a miniature cast iron dutch oven in his dresser drawer, but we're planning to move his collection into the garage due to both exposure concerns and radon buildup.

So I guess my questions are:

1. Is the garage storage strategy reasonably safe? The storage area is at least 10 feet (and one wall) away from the nearest bedroom.

2. How safe will it be for him to handle the lens? Aside from the usual (hand-washing, no eating or drinking while handling, etc), what handling precautions should be taken? Is there a maximum handling time to which he should adhere?

3. Should we be measuring his samples in micro-Sieverts or millirems instead of CPM? If my understanding is correct, those units are more relevant to dose/exposure and harm potential. And if that's the case, where does the danger zone start?

Thanks y'all. I love learning with my kid!

Imagine a spaceship that keeps accelerating at 1g (about 9.8 m/s²) for a very long time.

From Earth’s perspective, the ship can’t go faster than the speed of light, so the velocity must “flatten out” as it approaches c.

But from the ship’s perspective, the crew feels a constant 1g, and it seems like they can keep gaining speed forever.

How do physicists reconcile these two viewpoints? And how exactly do you calculate the distance and time experienced by the ship vs Earth in this scenario?

If an object is freely falling then it's acceleration is g pointing downwards at all times and it's velocity increases. So accordingly Newtonian momentum should increase and decrease the De Broglie's wavelength. But in case of a photon velocity is constant 'c' and it's momentum is constant. So what would be the change in de Broglie's wavelength if a body is in free fall or would there be no change at all

We have two 30 minute basketball games being played.

One game is being played near a black hole while the other game is being played back on earth. Assuming identical games,

All of the participants playing feel the same amount of time locally but WHY do the games finish at different times?

"For the basketball players near the black hole, time feels normal to them locally because everything in their frame of reference (clocks, heartbeats, thoughts) is equally affected. It is only when comparing to an outside observer that the difference becomes apparent"

Why does this happen?? No matter how many times I try to wrap my head around this I can't understand it