for questions about design, process, data, or analysis of experiments and observations.

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2
votes
1answer
41 views

What is the minimum sample sizes to show the error bar in an experiment?

In scientific experiment, people often try to show an error bar based on the standard deviation around a mean (average) value. My question is twofold: How to estimate the minimum but adequate ...
2
votes
1answer
36 views

Does the human body have a measurable gravitational field?

I am researching communication other than speech or vision. The human body emits radiation in the form of heat; As the body has mass, will it have a gravitational field?
0
votes
0answers
7 views

Optimum “fur” dimensions for absorbing ultrasound at a given wavelength?

By "fur" I mean an array of bendable fibres aligned vertically on a substrate. The ultrasound hits it at an oblique angle. Is there a spacing that will provide optimum absorption? A basic thought ...
0
votes
0answers
10 views

Methods for producing Molecular C60 (A.K.A Buckminsterfullerene) [on hold]

I wanted to know about how to produce molecular C60 - also known as Buckminsterfullerene/buckyballs. I read online that vaporising graphite in helium gas was how scientists initially discovered ...
0
votes
0answers
11 views

Intensity fluctuations at the output of a single mode fiber coupled to a He Ne laser

I have coupled a Thorlabs HNL050L-EC - HeNe, 632.8 nm, 5 mW, Polarized Laser to a 2 meter long single mode fiber patch chord using a Thorlabs F230-FC-B aspheric lens. While I am certainly able to ...
1
vote
0answers
33 views

Lab experiment: hysteresis disappears, reappears and then disappears again. How?

In my college laboratory we were assigned an experiment to measure the hysteresis curves of a certain ferromagnetic material at different temperatures. Sounds simple, right? Well, the block of Monel ...
0
votes
0answers
38 views

Speed of the Coulomb Field Measured To Be “Infinite”

The paper "Measuring Propagation Speed of Coulomb Fields" by R. de Sangro et al points out that: ...the Lienard-Weichert retarded potential leads to the same formula as the one obtained assuming ...
0
votes
1answer
16 views

Mach-Zehnder probabilities

Where can I find the computations of probabilities for Mach-Zehnder experiments, say at the undergraduate level? For example I'm thinking of the type of experiments described at the beginning of David ...
1
vote
0answers
29 views

Any method to determine the gravitational constant $G$ from observations in cosmological scale?

By the observations in cosmological scale, I mean observations by astrophysicists like motions of quasars in far distance from us, relative motions of our galaxy to others, etc. I know the famous ...
0
votes
1answer
27 views

Reverse osmosis Water desalination

Is it feasible to submerge a reverse osmosis system in the sea in order to use the increasing pressure to push through the membrane and as the salt was removed would the lighter water rise on its own? ...
1
vote
0answers
17 views

what is the effect of temperature on the resistance of a photoconductor?

As we know, for a photo conductor resistance tends to decrease with increase in irradiance, but with greater irradiance comes greater temperature. Also we know, photo conductors are ...
-4
votes
0answers
25 views

Einstein and his idea about infinite electricity [on hold]

What did Einstein say about infinite electricity? Did he say that,it is impossible?
0
votes
2answers
24 views

Probability of Millikan's drop gaining or losing charge during the experiment

I performed Millikan's experiment with latex drops. I did not get the "step graph" that I wanted (though the precision of the experiment was really bad as seen in the figure). My first drop is ...
0
votes
1answer
49 views

Coulomb law and photons

When we consider process like $e^- e^- \to e^- e^-$ in QED, we see that from exchanges of one photon (tree-level diagrams) one can obtain Coulomb's law, while loop-diagrams give quantum corrections ...
0
votes
0answers
21 views

What is the smallest practical milliKelvin temperature sensor or technique?

I need to track the temperature of a mass of less than 1 gram, and the two constraints are accuracy and mass of the attached sensor/circuitry (it must be less than 1.5g). Ideally it should be a non ...
0
votes
0answers
21 views

How does sound propagate through a mesh structure?

I am assuming that the material and holes are approximately the same dimensions and also similar to the wavelength of the sound. In my case, around 2mm. How does varying those dimensions affect the ...
-1
votes
0answers
28 views

Why use a LED light source in an experiment of fluid mechanics?

There are two main kinds of light sources used in the experiments: Laser and LED, which are very different in energy consumption as well as the wavelength range. I guess the reason is related the ...
0
votes
0answers
8 views

Change in Q factor on tuning external magnetic field in Electron spin resonance experiment

Does the Q factor of the cavity resonator show a dip at the resonant value of the external magnetic field while performing an ESR experiment?If so, what is the physical reason behind it?
27
votes
3answers
3k views

How can an electron fake a jet?

This is a question for experimentalists. I have seen in several ATLAS papers (see for example chapter 4 in arXiv:1602.09058, 6th paragraph), that after objects have been correctly identified, any jet ...
-1
votes
1answer
49 views

I can get a heating strip - why can't I get a cooling strip?

A typical heating strip is a flexible silicone material containing a resistive heater. However, I would like the opposite - something I can wrap around my experiment and use in a similar way to the ...
0
votes
0answers
29 views

Results with more data, do you have to correct? [closed]

For example,$$m_1 = \frac{\delta x}{\delta t_1 }$$ where $t$ is time. So if you get a gradient from one experiment and then repeat the experiment with 3 times as much timing data, but the $x$ value ...
0
votes
0answers
17 views

GEN3's 10nm-30nm Contiuum Radiation Measurements

What is the most likely explanation for the 10nm-30nm continuum radiation reported in "Validation of the Observation of Soft X-ray Continuum Radiation from Low-Energy Pinch Discharges in the Presence ...
1
vote
0answers
27 views

How is mass of observable universe calculated? [duplicate]

How is even mass of earth known ? How do we get to know them? Whilst I was studying about dark matter it was listed about 'mass of observable universe' and density and so on...so what is the ...
1
vote
1answer
125 views

Difference between theoretical equations and empirical equations

Some equations are theoretical in the sense that they are derived from an underlying theory. Other equations are empirical in the sense that they were selected only because they fit experimental data ...
3
votes
1answer
73 views

Measuring very long half lives accurately

There are already some questions about long half life times for radioactive elements, explaining how to calculate the half life time. Now I am wondering: When you have some radioactive material and ...
0
votes
1answer
21 views

Why is this ice cloudy at the center and has a transparent layer?

This fell at my place during a hailstorm. I can not figure it out why it is like this.
0
votes
0answers
7 views

Thickness uniformity comparison between a bilayer and superlattice

For a heterostructure grown using pulsed laser deposition to be used in polarized neutron reflectometry, is there any difference between a superlattice and a bilayer in terms of thickness uniformity ...
1
vote
1answer
26 views

Is it possible to measure the spin of an electron without moving it?

I know that the position and spin operators commute, so it is theoretically possible. What I want to know is, what experiments currently exist that achieve this?
1
vote
0answers
30 views

Is it possible to create a double slit experiment that can predict when photons have 'likely' passed through the slits?

This question asked:Is it possible to determine the slit a photon went through in the double slit experiment by measuring its flight time? My question is similar, but doesn't require such detailed ...
0
votes
0answers
21 views

How to get rid of optical reflections in microscopy?

I am running a Raman microscopy experiment with polished silicon wafers. Each time I make an optical image of the wafer surface, reflections appear to the left of the image. This is even worse for ...
0
votes
1answer
26 views

Is there any experimental evidence to distinguish the total gravitational force exerted by the two proton and a helium nucleus?

I know that the sum of the mass of the two proton is greater than the mass of a helium nucleus (two proton). As the mass different is transformed into energy by the Einstein mass energy-equivalence. ...
58
votes
9answers
6k views

What are the next generation physics experiments? [closed]

The LHC and LIGO are two recent examples of hugely ambitious experiments in fundamental physics, both of which took decades to develop. What are the next major experiments currently being planned and ...
0
votes
1answer
54 views

When does the shock occurred?

I'm between this 2 conditions that when does the shock occurred over an airfoil. When the speed of point of an airfoil reach to sonic velocity of environment. When the speed of point of an airfoil ...
1
vote
0answers
14 views

Making a conductive paint out of graphite powder [closed]

I want to make a conductive paint out of graphite powder and gum to use as an electrode. What shall be the best gum to use, as i need a low resistance of around some kilo Ohms. I am getting very high ...
0
votes
0answers
16 views

Why is graviton not found yet? [duplicate]

Why is graviton not found yet? Newton said gravity pulls us, Einstein said space is bent and it pushes us, hawking predicts the existence of graviton and 'hawking radiation'. How far are we from ...
0
votes
1answer
42 views

Angular Acceleration of a Pendulum

I am trying to work out the mathematics behind the design of an old mechanical brake tester. The device sits in the passenger foot well of a vehicle and tests the brake efficiency. The device is ...
0
votes
0answers
11 views

Temperature equalization by radiation between two coaxial cylinders - independent of diameters?

Ignoring end effects, assume I have a cylinder of diameter d0 at controlled temperature k0 and then introduce a smaller diameter cylinder of diameter d1 and temperature k1 to the interior. Does the ...
1
vote
0answers
36 views

Relevance of pure mathematics vs statistics to physics [closed]

For someone currently studying physics, with an interest in experimental physics, would pure mathematics or statistics be more relevant?
1
vote
0answers
19 views

How Does Silicon Surface Barrier (SSB) radiation detectors work?

I'm dealing whith some old detectors (about 1980) called Silicon Surface Barrier, searching online I've seen that they consist on metal-semiconductor(Si n-type) junction (schottky diode) and in one ...
1
vote
0answers
18 views

Polarized Coherent Beam Hits a Polarizer Off-Polarization Angle While Varying Distance?

Just wondering about an experiment that should be easy to perform on an optical bench: A coherent beam is polarized. It then hits another polarizer which is set to permit a polarization angle off ...
3
votes
2answers
50 views

Optics to correct focal distance across a plane

I have a laser beam which is focused to a point at a certain distance. I'm then going to use a galvanometer to scan that beam across a plane. Obviously, as the beam scans across the plane, the ...
1
vote
0answers
24 views

Logarithm of the voltage of the inductor in RL circuit experiment is nonlinear with time

I performed an experiment about the RL circuit, with following circuit: (I used the PASCO RLC circuit lab.) By Kirchhoff's voltage law, (denoting the emf of the signal generator $\mathscr E$, ...
0
votes
0answers
35 views

Finding the appropriate fitting function for a coherence length measurement

I'm studying Coherent Optics in Experimental Physics, and I intend to determine the coherence length of a two beam interference. To do that, I used an He-Ne laser, a Michelson interferometer and a ...
0
votes
0answers
15 views

Can energy be organised into elemental form other than hydrogen?if yes,then how?

I wanted to know whether energy can be organised into elemental form easily. If is so then , can antimatter be generated in a similar way other than pointing high intensity laser at some metal foils ...
0
votes
1answer
33 views

Excess corn starch in a non-newtonian fluid

I'm currently performing a high school experiment regarding non-newtonian fluid. And as a further exploration, I am aiming to figure out whether excess corn starch in the solution will cause a ball to ...
1
vote
0answers
22 views

Heat transfer with a small airgap - conduction v convection v radiation

I have a transducer approx 25mm dia x 25mm length which will sit inside a brass casing, but stood off from the walls by around 0.5mm. Obviously the brass is a far better conductor than the plastic of ...
1
vote
0answers
20 views

Why isn't every magnetic neutron scattering peak a nuclear scattering peak as well?

Neutron diffraction is a well-established technique for determining the magnetic unit cell of magnetic materials. The idea is that nuclear scattering gives you peaks that correspond to the crystal ...
1
vote
0answers
16 views

Explanation of two slit experiment [duplicate]

Whilst going through 'a brief history of time' ,I faced difficulty in understanding the two slit experiment. How can individual electrons cause fringes?
0
votes
2answers
16 views

Interpolating experimental data correctly (limited model knowledge)

I have data which I know follows a function $y = f(x)$ such that it is quadratic i.e. $y =\alpha x^2$ for some $\alpha$ when $x\rightarrow 0$ and $y = \beta x$ for large $x$. The data itself has ...
7
votes
2answers
165 views

The lightest photon ever detected

Wiki says that a photon of mass equivalent to $10^{-62}$ kg has been detected: 10×10−62 kg Mass equivalent of the energy of the lightest photon detected [citation needed] this equates to a ...