Measuring Definition and 1000 Threads

Hello all, I'm a bit new to to the forum, but from the posts I've read, I can say that this is a fantastic site. I have a fish tank with some live plants in it, and I add CO2 to the water by putting some sugar, water and yeast in a two liter bottle and pumping the gas into the water. Worked...

Hello all. I'm am a first time poster but a long time visitor. I am having a little trouble that I was hoping someone far wiser and more knowledgeable than myself might be able to help with. I've been using MCNP to investigate criticality in a simple geometry consisting of a central natural...

I hear a lot about astronomers using type IA supernovae to accurately measure large scale distances over billions of light years to do things like measure the rate of expansion of the universe. I doubt that the calculation of this distance is simply based on the inverse square law. So my...

would a 1.5 volt electronic device that measures capacitance to turn on or off a regulator that controls water flow affect a defibrillator or pacemaker? Another way to ask this, A kitchen faucet that is touch sensitive would be safe or not safe for a heart patient who has defibrillator and...

Homework Statement This is a lab problem and basically I am supposed to explore the properties of a capacitor. Here is the question that confused me

For the MMX, the speed of light is measured isotropically at c in free space regardless of the frame, so gives a null result. To another frame of observation, light still travels isotropically at c while the apparatus is length contracted by sqrt(1 - (v/c)^2) in the line of motion, whereby a...

Hi, Im currently doing an experiment with muons : detection, measuring lifetimes, mass etc. Im currently struggling with a basic measurement. I have a standard NIM crate setup, with discriminator, delay, coincidence units etc, and an oscilloscope. I have no user manuals for any of the units...

Homework Statement I 'm having a struggle on my A2 level physics course work. I need to carry out the experiment which is rolling a metal ball down a slope and with a different materials at the end of the slope to stop the ball such as elastic band, folded paper and balloon, the difficult part...

Hi all, I have run a few linear regression models predicting water quality for watersheds using explanatory variables such as mean impervious surface within watersheds and others suggested by theory and the research of others. I would like to be able to compare explanatory variables measured...

An apparatus has these properties when measuring a polarized photon: -whenever a linearly polarized photon at angle \vartheta enters apparatus, it displays "2" -whenever a linearly polarized photon at angle \frac{pi}{2}+\vartheta enters apparatus, it displays "3" -for all other polarizations...

Homework Statement I want to calculate the surface area, mapped with points. For starters, I've mapped the edge of a circle with 200 points, then created a few more circles, each with 200 points. The problem is I get different surface areas for the same size circles. The only difference...

Homework Statement We have a round disc with radius of 10 cm and mass of 1 kg, suspended on a wire and lying on a thin (1 mm) layer of oil. We torsionally nudge it and we get some info out of it: At angular velocity of 10 s^{-1} the amplitude is maximal. At angular velocity of 12 s^{-1}...

If there are 2 objects emitting light to each other and the light fills the spacetime between them and then that spacetime expands the waveform becomes stretched. However, if the middle of the spacetime between the 2 objects has yet to have light enter it from either object and that spacetime...

Hi everyone, I was just wondering if anybody can offer me any tips or advice for a project I am working on at the moment. We have been carrying out shot blasting using various abrasives to improve the surface roughness of some polypropylene parts that we are making for the medical industry...

If we were to measure the speed of light as the scientists in the 1800s did (such as Foucault and Fizeau), without knowing the relationship between speed of light and its wavelength and frequency, would it be possible to do so using only simple apparatuses like mirrors and low powered motors and...

Homework Statement How do you measure the output of a voltage divider with real voltmeters that have effective resistances Homework Equations The Attempt at a Solution I know that for an ideal voltmeter (one with infinite resistance), the voltage divider is R2/(R1+R2), but I...

Hi guys, I have problems with a high-school assignment: Homework Statement http://img843.imageshack.us/img843/3748/74698735.png An experimenter tries to determine the speed of sound in air. He tries to lower and elevate the water in the tube at the same time as he hits on the fork, until...

hi there, I have been studying the postulates of QM in shankar book, and in the part it explains how measurement affects the system, it talks alittle about the expectation value and the uncertainty. then I came across this problem which I don't get. it gives three L(in x direcion), L(in y...

In the double slit experiment - what exactly is the measuring device? .. the have to measure witch slit the photon went trough - how do they do it? - measuring anything means interacting with it. Changing it, really. So, isn't it obvious that interacting with the photon in any way will...

Ca. 1996 a colleague bragged to me about an undergraduate lab he'd worked out where they did a high-precision measurement of g (I think he claimed 3 sig figs) using an index card, a pin, and a stopwatch. He didn't tell me any details. I've long since lost contact with him, but I was thinking...

Hi, I'm a civil engineering student in a summer internship at the moment but I've come across a mechanical issue. We want to buy or build a very accurate (+- 100mm) odometer for a large truck. We have a Survmaster precision odometer in there but it's only accurate to +- 1.0m which isn't good...

Hi, how is the speed of light measured in objects such as water, glass, diamond etc ? what are the tools and techniques used. thanks in advance !

This is a (fairly basic) lemma without proof I saw in a research paper. Wasn't sure how to classify it exactly, but decided it's closest to vector (and linear) algebra. It goes like this, consider a quadrilateral in the plane with vertices A, B, C, D in clockwise order. It is given that...

Is it possible to use a balance to measure the mass of a gas? Let's say that the experiment I'm going to describe is possible and takes place in a vacuum so as to avoid any buoyant force from the surrounding atmosphere, and the balloon to be used does not allow any effusion of the gas from...

I need to devise a way to measure the torque of a Rotating Motor. Now i already have 2 ways in mind but both of them require that the motor stops while still being powered by a battery or something. ( I think we risk permanent damage to the motor ) Can someone point me to a method that...

Hello there, I'm an undergrad in my 3rd year and I'm doing an investigation into the 'Preparation of Thin Films and their use in Hall Effect measurements.' We are making thin films of bismuth on glass (with pre drilled terminals) in a vacuum system. The way they suggest measuring the...

Homework Statement well have this little problem for home work, I am to find out how to measure the preasure on the human leg or in my case a mecanic leg. there are different preasure oints as I understand it, with the foot. what I need to find out is what formulas would be used to both make...

Now here is a real world practical application. Australia Post has a warning for shipping magnetic material in the post. Section D2.9.2 states... Any material that, when packed, has a magnetic flux density of 0.159 A/m or more at a distance of 2.1 meters from any point on the surface on the...

Hello, I am new to this forum (and no physics expert). I apologize if this topic is in the wrong place, but I would really appreciate help on the abovementioned topic. I am investigating the effect of temperature on the capacitance of capacitors for a school project. Since C =...

Homework Statement I have tried to solve the displacement sideways of an lightray through a medium with snells law. The question is how much does the ray travel in x-direction in the new medium with width D. It says in the text that one should use pytagoras but I can't seem to understand...

In double slit experiment, what if we put a detector on one slit, instead of both slits. Does the interference pattern appear or not? I think, if superposition principle is true and particles passing through both slits at the same time, measuring one slit will be enough to collapse its wave...

Locally, Fermi normal coordinates are designed to correspond with direct measurement of distances (born rigidity). I also discovered that Synge's book on GR establishes that very locally, radar distance must match Fermi normal distance, but not in general (obviously). What I am wondering is...

In many equations, I see the term E, but I'm really confused on how exactly I can calculate this value. So if I were to an experiment and I needed to find the polarization density, and I needed the E value, where can I find it? Thanks :D

I was given the assignment to measure the parabolas of a suspension bridge. I have some ideas for how to go about it, like using a point of reference and going out from there. I was wondering if anyone had any other ideas. Thanks! Alex

Homework Statement Consider a particle-in-a-box problem, involving a particle of mass m subject to a potential: V(x) = +∞ for X≤0 V(x) = 0 for 0<X<L V(x) = +∞ for X≥L |ϕn> are the eigenstates of the Hamiltonian H with the corresponding eigenvalues: En = (n^2)*(hbar^2)*(Pi^2) / 2mL^2...

Hi, This is my first post on this forum, just joined. I recently purched the S3 Spyder III Arctic portable 1W laser from wickedlasers. I bought it to try and make some cool photographs and photoshop them. After testing the device (glad I bought safety goggles with it) I was wondering how hot...

Homework Statement A mass m is connected to a spring of spring constant k. The equilibrium position is x = 0 and the motion of the mass m is restricted by a stop such that spring compression is not allowed, i.e., x < 0 is forbidden . The system is in the ground state. (a) The stop is...

suppose I have a number of permutations of a vector of bits and i want to have some measure of how varied the sequence is. e.g. i want a single measure that can express the difference between this: 1010101010 and this: 1111100000 the measure would ideally place vectors on a spectrum so...

Hi, I was wondering how I would find the speed decay of a ball rolling in a straight line, if i were to measure the time it takes to travel a certain distance over and over. i.e >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> <---10cm--> <---10cm--> <---10cm--> ^ ^ ^...

I'm trying to help my 6th grader measure and graph the amount of power (eg voltage) her hamster will put out running all night long on it's wheel that is connected to a small DC generator. I am hoping to not buy an expensive DAQ and software. Does anyone have any ideas how I can do this on...

I am very interested in physics but have no background education on it so forgive me if this question is amateur. I am trying to grasp this redshift thing. It's the measurement of a shift in the wavelength of light. The only variable I can think of is the wavelength of the light received on...

Am reading the attached labscript. Finding it difficult to understand at places. Any good sources of further explanation on the Net or textbooks?

Suppose there is a quantity X to be measured. To do this you have a measuring device with a resolution of 1 and an accuracy of +/-1. It is imediately obvious that repeated measurements can yield an accuracy of +/- 0.5 but can any greater certainty be achieved? If 2 measurements are made and...

first off I'd like say thanks to everyone on here, I've lurked and solved many questions thanks to you guys. First post woo. Basically we were tasked to design and carryout a lab to measure the coefficients of friction between a wooden board and some random objects (teachers gone for a few...

Hi all, Im currently working on a project that requires me to continuously measure the density and thickness of a sheet during an extrusion Styrofoam process. I have researched sensors and have found some that will do the job but of course they are in the $10k range. These however only...

Howdy Yall, First time poster, long time lurker. I am working on a project right now measuring the "useful" life of a battery...say a AA battery. To relate that to a real world application, I will be powering a light (LED) off the battery. I was initially planning on getting the battery, an...

Hi there. I was recently working out some expressions in Electro-Dynamics, to calculate reflexion and transmission coefficients. Ok, I reach some Fresnel equations. However, real materials are not so perfect, in sense that they are perfect surfaces, with perfect everything. So, I wonder how...

Is there any standard way for measuring the metric tensor. Does it require the a priori specification of a coordinate system relative to which we measure the components of the metric, or is there a way to measure the underlying geometric object?

I just discovered about solar storm named "Carrington Event"; I'd like to know how such a solar storm could affect my PC today. I found some publications: http://www.bu.edu/csp/EMMREM/papers/carrington.pdf...

Hi all I am looking to measure minute changes in electric field strength. I found this article http://www.physorg.com/news74876394.html" which describes how scientists at harvard isolated a single electron in a highly evacuated, absolute zero chilled chamber and manipulated its movement using...