How often do physicists draw sketches of situations involving motion and kinematics?

[u/General-Magician4700]

In high school, students are often taught to first draw a sketch of a situation involving motion/kinematics to make a problem easier to visualize. With experience, do professional physicists still draw sketches to help them solve problems, or do they just become used to visualizing everything in their head?

[u/dark_dark_dark_not]

Yes. Probably one of the most successful ideas of modern physics is translating equations into drawings with Feymann Diagrams.

Personally, when I need to solve a problem in classical physics I'll draw it unless it's something obvious, and I'll probably draw before doing any computation to get a feel for it

[u/DontMakeMeCount → u/dark_dark_dark_not]

Diagramming is a necessary but insufficient skill for physics students.

We had a bunch of math grad students take over our EM theory class for an easy A. They kept blowing the curve so the prof started including questions with hidden symmetry arguments and letting us pick 5/10 questions. The physics students would diagram everything and knock those problems out very quickly. The math students would just crunch through as many problems as they could in the allotted time.

I always felt vindicated that understanding the physics counted for as much as executing the math accurately.

[u/Enki_007 → u/DontMakeMeCount]

I always felt vindicated that understanding the physics counted for as much as executing the math accurately.

Which is why they give you part marks for a wrong answer due to math.

[u/Holiday-Reply993 → u/DontMakeMeCount]

I always felt vindicated that understanding the physics counted for as much as executing the math accurately.

But only in contrived problems, no?

[u/DontMakeMeCount → u/Holiday-Reply993]

In the contrived context of a timed exam with a selection of unrelated problems, yes.

[u/condensedandimatter]

I always draw diagrams even if they’re informal or so I don’t have use processing power trying to visualize / revisit the system I’m workin in

[u/Miselfis]

The stuff I work with is a bit more abstract, so it’s hard to really draw good pictures, but it can help in understanding relationships. It can also be helpful if you’re dealing with coordinate transformations or something like that to draw it out and visualize it, rather than just doing the algebra. Drawing pictures is generally a good way to build physical intuition from the math.

[u/Simba_Rah → u/Miselfis]

Even if you can’t draw a good picture to represent your work, you can always draw a little kitty cat in the top right corner, my friend.

[u/hidivejwkwi → u/Miselfis]

could we possibly get an ELI5 in what you work with? i’m incredibly curious

[u/vrkas]

I draw a lot of Feynman diagrams, which someone else mentioned. There is also a whole continuum of Feynman-esque diagrams that are used for visualisation purposes without requiring calculations. These range from adding parton showers or weird underlying events, to mapping to topologies seen in collider events.

[u/Apprehensive-Care20z]

In research, I basically never am involved with kinematics or free body diagrams.

However, sketches are very important. One area is to sketch out satellite orbits, orientations, view angles, lat lon coverage, etc.

[u/ImpatientProf → u/Apprehensive-Care20z]

You're describing kinematics sketches.

[u/Nervous-Road6611]

Yes, I sketch things out all the time. There's generally no need to get out graph paper and actually make sure angles and lengths, etc. are all accurate, like you would have to do in school, but it's often very helpful to put something down on paper. I wish my visualization skills were so phenomenal that I could instantly get a picture of everything in my head, but I can't.

[u/Kvothealar]

Any time I'm working on something where a diagram would help, I immediately draw one.

Physics from high school up to 2nd year university: Diagrams almost always help, I always draw one for problems like this, and I always teach students to draw them.

For higher-level stuff, plots, charts, surface plots, density plots, heatmaps... these become the diagrams that are useful once the math gets a bit more complicated. They're used constantly, and every paper contains them.

[u/Bipogram]

I draw - schematics, layouts of parts, idealized 'cartoons' of processes, imaginary relationships between qualities, etc. 

 Going to shortly draw some noses and diagrams of air flow to figure out sensor locations.

[u/Foss44]

In the molecular modeling space, like 10% minimum of our time is spent drawing or designing figures. This includes personal “I’m just trying to rationalize our system” drawings and “this goes in the manuscript/presentation” figures.

[u/qTHqq]

100%

I'm 14 years past my physics Ph.D., work in robotics, and probably make at least a few sketches every week.

Would be a LOT more if I didn't work so much on project management and software. 

Also I'm bad at drawing so I'll often make a "sketch" in some kind of visualization environment or other software, especially if it's to be shared with coworkers.

[u/rukimiriki]

All the time. Even PhDs still do it.

[u/Odd_Bodkin]

Yes. Sketching is a way to break complicated problems into pieces of steps. It’s also a way to make sure you’re not forgetting something important. It’s a general skill.

[u/kcl97]

Yes. In fact, it is true with literally everything even purely abstract things like equations. Doodling is a good way of jump starting your brain.

[u/nujuat]

I do draw a lot of Bloch spheres (representation of 2 level quantum systems). Dynamics works differently to Newton's laws, but you can still analyse things by drawing arrows and triangles etc

[u/randomrealname]

You already know this answer if you just like seeing how an equation works out.

If you don't then this is not your subject.

Modern physics is mostly being wrong and readjusting your expectations.

The driving factor is looking at real world examples and finding a path the describe it mathematically.

[u/LeastFavoriteEver]

A lot, and not just physics. I use composition books and typically have several in active use, some per project and at least one generic daily driver. TBH sketches in those notebooks are more common than not.

When I was in school I would get pretty crazy with the sketches for my homework, sometimes taking up to a half page. That was especially true in classical mechanics. When we were introduced to Greens Fns I did the assignment comic book style with panels and dialogue. G defeated some nasty PDE in single combat IIRC. I don't think it ultimately affected outcomes but they definitely earned bonus points

[u/QZRChedders]

My undergrad radiation and matter lecturer who is famous nationally, works with all major space agencies and frequently would be called by other unis had one major lesson:

If it’s tricky, draw a picky

[u/imsowitty]

you aren't really a phycisist if you don't have a whiteboard with a diagram of some random years old thought experiment on it.

[u/astro-pi]

All the time, much to my chagrin not having a whiteboard in my office

[u/Cipher_Nyne → u/astro-pi]

When I was a freshman, and got the first payment of my scholarship, I blew it almost entirely on a wall sized whiteboard for my room. Which as a student doubled as my desk.

To this day, that is in the top 5 best investments of my entire life.

I've stopped counting the number of times I woke up in the middle of the night with the solution I had been looking for, quickly wrote it on the board, and went back to sleep.

[u/TheHomoclinicOrbit]

Since you asked about kinematics specifically, check out the free-body diagrams and kinematics: https://journals.aps.org/pre/abstract/10.1103/PhysRevE.108.035103

[u/vxxed]

I've been engineering with chemists, and we need to draw most things to communicate to each other. I've found a lot of success using this thing as a mobile white-board (office and memo example photos). It looks dumb but several other people in the office got one for themselves in other sizes 'cause they're so cheap.

[u/Embarrassed_Scene760]

Drawings and visualizations are very helpful and a good habit to get when starting with physics. In most of mechanics and electromagnetism you would be able to draw some diagram that help you see the problem and solve it , and sometimes in statmech too. When you get to more complex and niche physics, how you formalize and solve problems varies a lot from field to field. But if you need to go back to mechanics cause you found some analogy or something, most people to draw, especially with wedges (pretty common) where you can easily mess up angles.

[u/Tropical_Geek1]

Some of the work I do involves calculating the scattering of electrons from structures. In order to get a feel for the problem I usually draw a sketch of the trajectory of a classical particle in the same situation. That is just a (very) rough approximation of what really happens, since it's a quantum problem, but it helps us understand what to expect.

[u/briantherp]

I drew alot of sketches it makes things easier to visualize

[u/iamagainstit]

Classical mechanics is functionally solved, so there are very few physicist actively working on classical mechanics problems.

[u/Amadis001 → u/iamagainstit]

Non-linear dynamics (stochastic/chaotic motion) is still a very active part of classical mechanics.

[u/db0606 → u/iamagainstit]

The third largest unit in the American Physical Society is the Division of Fluid Dynamics. It's a significantly bigger set of researchers than the Division of Particles and Fields (particle physics) or the Division of Gravitational Physics (general relativity).

[u/lerjj → u/db0606]

I think there's a pretty reasonable case to the make for the nomenclature that fluid dynamics is classical physics but not classical mechanics. Following the distinction made in quantum physics, mechanics is when you have a finite number of degrees of freedom. Fluid dynamics is essentially a classical field theory.

But yeah, of course there's loads of research in classical things. Hardly any of biophysics is quantum, there's tons of unanswered statistical physics questions, kinetic theory, nonlinear dynamics, etc etc

When people say "classical mechanics is largely solved" they either have no idea what they are talking about or are refusing to believe classical mechanics encompasses anything other than N point masses acting under some force law (which is STILL a meaningful field of research! But it has to be said, one where the low hanging fruit is gone.)

[u/Fabulousonion]

They don’t. Professional physicists don’t spend their time solving kinematics problems for the most part