I'm getting mixed answers when I do google searches and hear from people but for the most part a lot of the scientific people tell me no. The 4th dimension is the space between objects.. Which gets really confusing.. There is even a 4D cube they call the Tesseract? I can't imagine it in my head I really can't, but the key component is, it needs to keep spinning, or it'll just look like a regular 3d cube with more lines.

For the longest time I always thought time is the 4th because if you go to an interview, they give you the streets, floor and tim to meet.. The interviewer just gave you 4 dimensions and we don't even think about it!

However, if Time isn't the 4th dimension, then what is it? Some body at this youtube video made a really good point. If time is a dimension, it's not the "4th" because it would apply in 1d, 2d, and 3d as well. So my stupid theory is maybe time is the first dimension? Even if you have a dot that can only move in 2 directions in a 1D world, you still need time in order to move from point A to B. Therefore it doesn't just simply appear after 3 dimensions. But maybe dimensions come together, they do not need to come in order, so time can be any of them without us acknowledging it.

I don't know, I used to study physics when I was in college but it's been a while. My professor was one of those who said time is not a dimension and gave me a lengthy explanation and it went over my head. First time poster. Nice to meet you.

This is a dedicated thread for you to seek and provide advice concerning education and careers in physics.

If you need to make an important decision regarding your future, or want to know what your options are, please feel welcome to post a comment below.

A few years ago we held a graduate student panel, where many recently accepted grad students answered questions about the application process. That thread is here, and has a lot of great information in it.

Helpful subreddits: /r/PhysicsStudents, /r/GradSchool, /r/AskAcademia, /r/Jobs, /r/CareerGuidance

There has been debate as my department begins deciding on our Fall grad students.. and it seemingly is coming down to weird details like this between some of the final picks. I’m not involved in the decision making but it got me thinking about what is considered better to some people?

This thread is a dedicated thread for you to ask and answer questions about concepts in physics.

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So, what do u all do for living after graduating with a physics degree. If you are in Academia, what are u working on and does it pay well?

https://home.cern/news/news/physics/alice-finds-first-ever-evidence-antimatter-partner-hyperhelium-4?fbclid=PAZXh0bgNhZW0CMTEAAaa8nR_IbiUQZAPFeqGPMPH4QH3hiVfmOxifd4IRB7AeNdRgsc58CMDITTs_aem_oYYyx-5rSXYNogRo4G2tSw

I am a 1st year Theoretical Physics but I am slowly realising I am bad at Physics and okay at Maths. Then, I wondered whether Mathematical Physics is more ideal for me.

Anyway, my question is: how exactly does it differ between a physicists and a mathematician doing maths?

Obviously we have different research topics but other than that, let's assume a physicist and a mathematician is approaching the same problem. What would the difference be? The obvious one I have in mind is how rigorous we are (my maths module lecturer from the physics department literally doesn't care about the modulus for , say, integral 1/x dx)

Hey guys! You all probably know what a cloud chamber is (if not, it's basically the simplest particle detector you can build at home, great for visualization and teaching), but If you ever tried to build one, you probably noticed just how different the instructions on Youtube and the internet might be. I recently worked on a project for school where I tried to improve the cloud chamber as much as possible, and wanted to share what worked for me and didn't. Note: though I tried to justify my results scientifically in the study, it still might be wrong and my suggestions might go against theory, in which case please correct me. Also, some of these tips might be already available online, and I don't claim to have invented them. Anyhow, here's a list of suggestions:

- For starters, check out the two following videos: 1) https://youtu.be/xky3f1aSkB8?si=VGAR5G1y6HTRyX3f and 2) https://youtu.be/eh3bxXHqF2U?si=zh_Ju3Gc150XQVr8 . I found these resources extremely helpful as the initial guide. The CERN one uses a metal sheet with grooves, however these are hard to find or do by yourself. So, follow ElectroBOOM's suggestion to make a silicon groove, it generally helps with the sealing and fixes the chamber container in place.

- Use glass or plastic for the chamber container. Some people suggested using plexiglass, which I ended up using, and do not recommend you do. Since we cool the chamber, the low temperature ended up cracking the container for me, leading to leaks at the bottom. Generally it's easier to get a ready container (from cooking sets or smth) rather than building you own, cause mine was imperfect and had gaps, which I had to glue together for some time.

- For the alcohol absorbent, use felt, not sponge. Felt can collect more alcohol and generally spreads it better than sponge. Also, the felt should cover the entire area of the top layer of the container, as it evenly spreads the alcohol. The felt layer should be quite thick (around 3-4 cm), as it allows to pour a sufficient amount of alcohol.

- Concerning the alcohol itself. It's best to use isopropanol, but for personal use different alcohols (methanol, ethanol, etc) are quite sufficient. I personally used ethanol because isoprop isn't sold in my region. Try to hit >90% purity - generally the higher you go the better the tracks. The cloud chamber has a specific limit of alcohol quantity where it actually operates, i.e if you poor too little or too much, it won't display tracks. If you have the time, try to play around with the volume of the vapor to see where this region lies for you - you will also see a change in the quality of the tracks, as some volumes produce a high number of tracks, others display them for longer. But if you're low on alcohol or just want to see the chamber work, the rule of the thumb is to cover the entire area of the felt and pour out the excess.

Also, the waiting time until the chamber actually starts displaying particles varies based on the amount of alcohol you add. So, for smaller volumes it took me about 10 minutes to start up, and 20 for higher volumes.

- For the metal sheet (which you place on top of your cold layer, where you actually see the tracks), try to find a black one. Aluminum, etc won't display as good and reflects light.

- The temperature gradient between the top and bottom layer plays a big role. It's best to get the bottom layer as cold as you can by using dry ice. Flaked ice worked best for me, as it covered the whole metal sheet area. Pellets work good as well. But if you plan to make more of a "perpetual" cloud chamber, go with Peltier coolers submerged in frozen salted water. This, however, will deteriorate the quality of your tracks, so judge based on your use. You can place hot water on your top layer, which will also improve your quality. I tried making a chain of resistors to heat the felt directly, but failed to do so. Maybe you'll be able to make it, but please be careful and look into it further because I'm not sure if it might actually ignite the alcohol :)

- If you want to produce more tracks rather than relying on cosmic rays, order smoke detectors with Americium-241 (I got them off of Aliexpress. Bought 10, only 3 produced decent results). Some recommend thorinated welding rods, but I went with the detectors. Remember radiation safety. Also, place the detector inside rather than trying to produce tracks from outside the container, plastic blocks off the particles.

___________________

Hope this helps! Have fun, I loved my experience with the chamber.

Edit: If you're concerned about the price of the chamber, the whole thing cost me around 30-40 usd, 20 of which went to the dry ice order. So shouldn't be too much

We were lucky enough to have Barry Barish speak at an informal round table event at Stony Brook University, and someone asked how to deal with imposter syndrome, feeling like every other student/physicist could do everything so much better than you, like you could never do anything significant next to them.

Barish explained that he felt particularly inadequate when he went to sign off on his Nobel Prize.

"Getting the Nobel Prize is this whole week long process, and I'd been doing well so far. The last day, they took us to get the money, take pictures, do all the important things. They came up to me with this nondescript, small book, and opened up this page that was blank except for '2017' at the top. 'Sign here,' they said. I signed my name, and flipped through the book. I saw Einstein, Feynman, all these fantastic physicists who changed the world... how could I be in this book? But I had already written in pen, so I couldn't erase my name."

I hope this brings you guys as much comfort as it did me, that even the most accomplished physicists feel this way at one point or another.

This is a thread dedicated to collating and collecting all of the great recommendations for textbooks, online lecture series, documentaries and other resources that are frequently made/requested on /r/Physics.

If you're in need of something to supplement your understanding, please feel welcome to ask in the comments.

Similarly, if you know of some amazing resource you would like to share, you're welcome to post it in the comments.

This is a dedicated thread for you to seek and provide advice concerning education and careers in physics.

If you need to make an important decision regarding your future, or want to know what your options are, please feel welcome to post a comment below.

A few years ago we held a graduate student panel, where many recently accepted grad students answered questions about the application process. That thread is here, and has a lot of great information in it.

Helpful subreddits: /r/PhysicsStudents, /r/GradSchool, /r/AskAcademia, /r/Jobs, /r/CareerGuidance

Hi all, not sure this post is allowed, in case not, feel free to remove it. I was thinking of buying a 2025 paper calendar as a decoration and I was looking for a science-themed one (preferably physics) do you know of a nice one? From a place that posts in Europe possibly.

This is similar to a previous question on fusion energy, which I'm really curious about the answers for quantum computing too.

I believe there's always some nuance involved in these fields dedicated to building these technologies that're hailed as breakthroughs, it's not all or nothing.

With all this research going into it, there's bound to be at least some useful research done that could benefit other fields right? Be it on the experimental or theoretical side?

This thread is a dedicated thread for you to ask and answer questions about concepts in physics.

Homework problems or specific calculations may be removed by the moderators. We ask that you post these in /r/AskPhysics or /r/HomeworkHelp instead.

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Paper is open access - link to paper

Great Blog by Prof. Stacy McGaugh - The most recent post is about his and collaborators recent paper about JWST results and structure formation. Link to blog

Highly recommend the blog, whether you are interested in Galaxy dynamics or not, simply because it is great and McGaugh has all the hallmarks of a good guy and great communicator. As ever, judge the physics for yourself.

My reason for getting into and being interested in physics is quite odd now i look back on it, but i got interested in physics when a truck went past me going quite fast which generated a gust of air/wind

Then i started to think about how and why that happens, so i went home that day and started doing some research, and from that point on, i was hooked.