#Physics

So I've been reading up on basic quantum mechanics, and the chapter on entanglement completely lost me. The book described particles somehow sharing states across distance — it felt like both a breakthrough idea, but also the most confusing one I've ever tried to parse.

I know I'm asking a question people here are already way better at explaining than I can be, so what resources do physics folks recommend when the going gets steep like this? Good physics-focused YouTube creators, authors who write for people new to this, or even just book titles I could track down? Something that explains entangled particles as if by analogy, maybe?

My last attempt at studying this ended in head scratching like, How is measuring one particle a dealbreakership thing at the quantum level. The whole concept smells like I've somehow not yet understood the basics yet, which would be annoying after reading the same textbook for four months. 😊

Anyone experienced the same confusion? If so, what helped your mind make this all stick better than quantum foam in a collapsing waveform?

Everyone cites Newton's cradle as a 'momentum demo' but no one mentions it's a kinetic energy illusion. The math checks out only if you assume perfectly elastic collisions between identical masses. Which no real-world material achieves. Try replacing one steel ball with a rubber one and watch the 'laws of physics' vanish. Car crashes are a better example of kinetic energy transfer. No one cares about momentum there. What other textbook examples are just lab-idealized parlor tricks?

I've been tweaking my 42ft cutter and installed a rotating keel system (model K-2000) hoping to harness the Magnus effect The manuals claim that at zero apparent wind the spinning foil generates a forward thrust that completely negates hull drag, letting the boat glide without any sail power.

I've measured the speedometer and it does seem to pick up a few knots when the keel spins up, even though the sails are furled. Is this really how the Magnus effect works on a keel, or am I misreading the data? Any physics‑savvy sailors out there who can explain why a rotating foil would produce thrust without any angle of attack?

Thanks for the help!

so i was bragging about how angular momentum is always conserved like it's a law of nature lol then someone dropped a quick example of a spinning ice skater pulling in arms while a gust of wind pushes her i realized i ignored external torque from the wind yeah i was wrong, thought conservation was absolute even with forces acting anyone else fell for that? tbh i feel kinda dumb now let's hear your worst physics oops moments

I have a physics class that covers differential equations, and I'm having trouble grasping the methods for solving them. I tried the textbook examples, but I still can't see how to apply them to real problems. I also feel like I'm not using my time efficiently. Any suggestions on how to structure my study sessions, or resources that explain the concepts in a more intuitive way? Also, would it help to focus on specific types of equations first? Thanks.

I was just thinking about sailing and how the physics of it all works. But then I started thinking about fashion and how some clothes just don't make sense from a functional standpoint. Like, have you ever tried to walk in heels on a windy day? It's like the designers never considered the actual physics of wearing their creations. I feel like they're more focused on making a statement than making something practical. Maybe I'm just being too perfectionistic, but it bugs me when form doesn't meet function. 😒

so last night i was streaming interstellar and on the news board they said 3020, I went looking up 3020 but that's out of scope for relativity haha my brain looped to 2030 instead tbh I realise that slip makes everyone question the film’s timing and the community lesson: jot down any off‑years in your margin doesn’t hurt if you ask for sources instead of guessing, way better than adding another physics factoid that might be wrong at home rn

fr so i dug out a 780nm ecdl, set the wiggling piezo‑stage to tweak the laser focus. i baked a simple rb‑87 trap with a few diode lenses, hit it with a 7µs pulse, and grabbed the photons on a scmos (it’s got the low‑noise we need). then i wrapped a pi zero with a low‑latency hdmi hat to run the 120fps capture and sent the stream straight to my 55" tv. the result looks like a floating green halo that slithers through a dark moat—pretty much quantum tunnelling on movie‑screen level.

technical bits if you want a cheat sheet:

• diode laser (external cavity, 78.0–78.0 ghz offset)
• 75 v piezo drive (20 khz bandwidth, <0.1 µm jitter)
• vacuum tube (~10–³ torr, stainless‑steel)
• ccd/cmos (andor zyla) at 400 ms/s
• pi zero w, hdmi‑zero (1080p, 60fps) as mux
• custom opencv script to slice intensity contours and boost contrast (saves 90% of the noise

this set‑up won me an extra 700 hrs of “eerie” movie time tonight. if u got an extra rackspace, laser lock board, or wanna swap the probe frequency, let’s sync.

edit: a tiny note — when you run the wavemeter every 45 min it cuts off any drifting into another isotope. dont forget to align your beam to the lens‐coil magnetic field axis—my bad, i had the polarisation off 180° last night.

bigger aim? sprinkle this on your favourite action film to give a realistic feel to teleportation scenes. think about how the pov lens can dramatically reflect quantum mechanics just like a slow‑motion shot, but still grounded in lab physics. drop any questions or tweak ideas. cheers

People always say plants need the 400‑700 nm spectrum to photosynthesize, but my 450‑nm LED strip is doing the job. The textbook says anything in the photosynthetically active radiation (PAR) range works, but that range is just a convenient band. If the photons are energetic enough to excite chlorophyll, why can’t we just use a narrower band? My philodendron’s leaves are greener than ever. Maybe the 400‑700 nm rule is just a marketing myth.

Also, the absorption spectrum of chlorophyll a peaks at 430 nm and 662 nm, yet plants still grow under LEDs that emit at 450 nm. So what’s the point of the 400‑700 nm band? Is it just a convenient marketing tool? I’d love to see a peer‑reviewed study that shows plants fail under 450 nm only.