According to my understanding of how noise-cancelling headphones work, the headphones detect low-frequency ambient noise levels near my ears, and emit a frequency which cancels out the ambient noise, so that instead I hear silence in place of the noise. Although I can't hear these noise-cancelling frequencies, I'm wondering whether they might be having a cumulative negative effect on my hearing. Is it only audible frequencies that have the potential to harm? Or can prolonged exposure to inaudible frequencies have a detrimental physical effect?
I'm an (older) grad student doing research in applied physics. I've ticked all my class requirements but have a shortlist of subjects I feel would be useful to my research and my career. I've translated these into a list of reputable, recommended textbooks to read. I've started reading those, usually in the evenings after all daily tasks are complete, and I enjoy it very much - but does anyone have tips to maximize the payoff of those reading hours? [more inside]
So, imagine we have a 100 meter tall tower, a 100 kg weight, and a rocket. Consider the following two, very similar scenarios... [more inside]
Hi everyone, My younger sister is 12, very smart, and has expressed interest in becoming a scientist. She loves physics and astronomy, especially, but she may have some untapped interest in other scientific fields as well. [more inside]
Career-advise me! Fellow mefites who enjoy both the humanities and the sciences: which did you pick for your career, and why? Or: were you able to somehow combine the two? Bonus points if you have experience with the medical field. [more inside]
I have a physics question, but my googling hasn't been able to provide anything satisfactory tonight. It's about cosmological models of creation in which NO initial conditions whatsoever are assumed. [more inside]
Where can I find royalty free photography and art for science fiction and space? Things like black holes, worm holes, spaceships, and futuristic technology? I'm looking for something with a Weyland Industries vibe to it.
Neal Stephenson's new novel, Seveneves, starts with the moon breaking up into seven pieces (spoilers for the first 50 pages of the book inside). [more inside]
So I have a few years to kill and I'd like to spend them fully understanding what physicists and mathematicians know about time. I'm not looking for any sort of summary, I want to understand the math from the bottom up. I once caught my father going through the Annus Mirabilis papers with a red pen; that's the sort of proficiency I have in mind. [more inside]
I need help evaluating different career paths as I plan a move to Rhode Island; I have a PhD in physics. What careers should I be looking into and what skills should I develop to have a very good chance of landing a job in under a year? [more inside]
After seeing Furious 7 this weekend, a physics question came up about weight and leverage. Spoilers and such below the break. [more inside]
I got accepted to two PhD programs in physics, one at Clemson University, and the other at Ohio University. I have one week to make my decision and I'm frankly terrified of making the wrong one. I don't really know how either school is seen in terms of what a degree from either one would mean for my future career. I know that neither is particularly well known or prestigious (at least I'd never heard of them before I applied). So, can anyone, especially anyone who knows the ins and outs of grad school, and particularly anyone who has attended either (or both!) help me make my decision? [more inside]
Earlier today I was warming up a test tube in chem lab by placing its bottom in a warm stream of water from a faucet and I noticed something peculiar; the stream of water seemed to capture the test tube and hold it in place. [more inside]
Another question from the "things my 9-year-old asked me and Google can't find" file: what would happen if you tried to hit a major league fastball with a tennis racket? Would the ball rip through the strings? Or would you actually be able to hit the ball back with distance? Would you hurt yourself?
I am looking for a resource that lists probability distributions and their common real-world applications. For example, I'd expect to see: Lognormal - daily returns in the stock market. Poisson - failure rates for mechanical equipment, ... [more inside]
What happens if your group exceeds the weight limit on a slide at the water park? [more inside]
If you dove into an 11ft pool of baby oil, would you be able to push yourself to the surface or would you drown? AKA what allows us to float? [more inside]
Many sites say that the largest known prime is "2^57,885,161 − 1, a number with 17,425,170 digits." Given this and well known research about the density of primes, I think it's at least possible to estimate the number of primes between 1 and 2^57,885,161 − 1. But I don't know how to do this myself. I really want the answer to this one (the order of magnitude at least), but I've got lots of these, and I'd ideally like more cool ones. :) [more inside]
I have a B.Sc in computer science and have one year of experience English using my CELTA qualification. Looking around, I see a lot of requests for people with North American B.Sc's to teach Math/Physics/CS in Asia. I'm trying to decide whether to go and start teaching, or whether it is better to get a state teaching qualification (2yr) in the Netherlands first... [more inside]
I'm sure you've all seen the quite obvious and silly "gravity will fail" hoax. It got me wondering...if all the planets, stars, asteroids, comets, black holes, etc (basically all known physical matter) were to somehow align on one side of the planet would the cumulative gravity exceed Earth's? I asked my dad (a doctor of nuclear chemistry) and he was stumped. Exclude dark matter for these purposes.
How do I calculate the radiation energy that a surface / object receives at distance d from a light source of power W watts? I'm familiar, in theory, with the inverse square law but need help thinking about how to apply it. [more inside]
I have been invited to dinner at the home of Russian emigre's who are both physicists. I work administratively at a medical school. The context of the dinner is that the couple are clients of my partner, who is an artist. Other than Putin jokes, or asking them to explain string theory, does anybody have any suggestions for conversation starters that won't make me seem like I failed my "physics for poets" class in undergrad? [more inside]
Quantum physicists of MeFi: I want to know all the quantum mechanics I need to know to understand quantum computing. I am mathematically literate and willing to learn more math, but I want to minimize my need to study physical phenomena or experimental results. [more inside]
I have a hose that can put out water at 60 litres per second (16 gallons per second) and I want to know if this hose can roughly replicate a wind speed of 275 kilometres per hour (170mph). We will put an object right in front of the hose - so there will be little pressure fall-off from the hose. Is this conversion measurement at all possible? I don't mind if the answer is a little approxiamate.
I need help thinking of cool ways to spend $30k or more for high school physics equipment! If you're a physics teacher, or had a great physics teacher in high school (or college), tell me what equipment makes for inspiring and effective physics education. [more inside]
My co-authors and I recently got a paper accepted to a major scientific journal. If we can provide a striking illustration, I think we have a decent chance to make the cover. That would be really cool and might be worth paying an external illustrator for. I never commissioned any artwork before, so I have questions about how to proceed. [more inside]
A couple of years ago, I graduated from [famous university] with a decent bachelors in physics. Since then, I've been working in a job which I'm going to be slightly opaque about, but I'm basically a ‘radiation physicist’ who gets paid by the government. I'm finding lots of aspects of this job unsatisfying and I'm looking for a career change. What are good avenues to explore for physics graduates? [more inside]
My apartment is on the top floor of a single family home. My landlord has advised that we open the skylights, one in the bathroom and one in the stairwell, to help keep the house cool. We have a window AC unit going in one of the rooms (a bedroom next to the bathroom with the skylight). It seems like opening skylights would let the cooler air out, like any window. What is the right move here to keep the apartment cool? [more inside]
I'm seeking recommendations for documentaries or books that offer more than a layman's explanation of Einstein's Theory of Relativity, but don't require advanced studies in astrophysics to comprehend. [more inside]
As a by-product of this FPP about a very large water slide, have just been involved in an inconclusive and heated argument about the physics aspects. Hypothetically, what would happen if, halfway down this very fast waterslide in a raft, you (accidentally or deliberately, it doesn't matter) defecated? [more inside]
I'm looking for interactive activities that will help to teach physics for a bright 10-year old. [more inside]
So, I recently got selected to do undergraduate physics research this summer. Great! Awesome! Yay me! However, my research advisor has asked me to use something called IDL to analyze tomographic images of compounds and turn them into 3D images. This is good news, because IDL is used a lot by astronomers to analyze astronomical data, and I want to continue my education in astronomy. But, I've never used IDL ever before. I'm not even sure exactly what it is (a programming language?). My question is this: how do I get up to speed so that I can hit the ground running with my research? Difficulty: Research begins in two weeks. Details: [more inside]
It's spring and the plants and trees which have been bare for months are bursting into life. I've been thinking it must take a lot of energy for a tree to go from having no leaves at all to being covered in too many to count in a relatively short period of time. But how much energy exactly? [more inside]
Where do you go to learn about theoretical physics, other than a university? [more inside]
For the grad-level education I want, I need an understanding of chemistry, physics, and calculus at a minimum. I have a BA in a tangentially related field (or will in a couple months). What are the best resources for learning these subjects without spending even more time/money on tuition? [more inside]
If I tie a 10N weight to a balloon and fill the balloon with helium so that the weight is lifted 100m into the air, then 1kJ of work has been done. Who did that work, and when? Who lost energy?
Hi there, I’m in a conundrum - I hold a Bachelors Degree in Physics and I am currently searching for a Master’s Programme at a German University specialising in the management of Oil resources and/or the relation to Oil and Physics that I studied. [more inside]
For my pal...What is a good physics study guide for: a) 1st semester algebra-based college physics b) lots of solved problems c) without calculus. I remember liking Schaum's in undergrad, but I seem to recall it being calculus based. Thx Hive!
My son is a junior physics/math major at a small midwestern state university. He needs to start looking at graduate programs. He would prefer to stay in research or academia. How can I help him start this process? (B.S. for me) Location is not an issue. It's more a question of what programs offer the best opportunities and fields of study. How can we find out that kind of information? How can I help him start with a reasonable number of candidates?
Physics geeks! Help me save energy! How do I estimate how much less energy will be used by light siding vs gray siding, based on an experiment with small boxes? I made some identical boxes, put them in the sun, measured temperatures, and am trying to figure out how to scale up. The net has info about different roof colors, but not siding colors. [more inside]
I'm a science teacher who is trying to take prerequisite courses in order to eventually apply for a graduate physics degree. The problem is as a teacher I work a set schedule everyday, and the pre-requisite classes I want are designed for the first-time college goer who is attending school full-time or has a part-time job at night. How do I get the classes I need? [more inside]
Help me find a new career where I don't have to take my job home with me. [more inside]
I have a large road case (2.5 / 2.5 / 3 feet) that I need to weigh. It is too big to fit on one scale. Would it work to place one scale under each of the 4 wheels and average the 4 weight readings? My physics-fu is not strong enough to figure this one out on my own. Help!
Just curious why the motorcycles don't completely tip over when they corner in the motocycle races? [more inside]
Trees in deep snow often have a gap around them where the snow is lower (see here and here). Why is this? Do trees give off enough warmth to melt snow, or do they absorb the snow as water, or is it because falling/blowing snow is blocked by the tree trunk, leaving a kind of shadow?
What is "electric potential"? I've dug through the internet, gone to tutoring, asked my teacher, and nothing has helped. [more inside]
When I hold out a weight at arm's length, I am doing no work (which, in physics, is motion over a distance against a resisting force, iirc) on it, because it remains stationary. But it feels like work! What about at the level of biophysics? Is keeping the muscle fibers of my arm contracted doing work in any way, perhaps at the cellular level?
My friends and I are having a nearly friendly debate about the effects of superhydrophobic coatings on various items, and we've decided to look here for more input. [more inside]
Until last night I was unaware that the hollow earth conspiracy was a thing. Since then, I've been driven crazy by trying to imagine the physics of it. What would gravity be like on a shell planet? Details about the exact setup within. [more inside]
I have sort of a bozo question about insects and physics. Why is it that when I shoo a wingless insect from, say, my arm, said insects falls the human equivalent of many storeys to the ground and doesn't die? Physics was never my forte, but this seems to defy some basic law, does it not?