The use of methods from the physical sciences to aid in the study of biological systems. Note that biophysics questions are only allowed if they are mainly about physics.

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15
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2answers
45k views

Effects of a very large magnetic field on the human body

Ever since reading about the NHMFL I have always wondered about this and asked several people without getting a good satisfactory answer. My question is, considering the simplest case let's say a ...
2
votes
0answers
118 views

What is the maximum magnetic field that a human body can withstand? [closed]

Are there limits to the exposure of human bodies to magnetic fields? What happens if we cross that limit? How to create such magnetic fields? Has this been tried out?
6
votes
0answers
101 views

How do proteins perform their function? [closed]

Let's, for example, take a ribosome. It is an enzyme that is in turn just a molecule that must follow the laws of physics. Correct me if I'm wrong, but it can be looked upon as a molecular machine ...
0
votes
1answer
47 views

Is there a pressure differential between the skin and any parts inside the human body? [closed]

Since most of the human body is never directly exposed to the atmosphere, is there a meaningful difference in pressure between any internal organs and the skin? If so, how do open wounds which ...
4
votes
2answers
168 views

What will happen to a human being exposed to Martian atmosphere?

Mark Watney, in the movie The Martian, says that, If the HAB breaches, I'm just gonna, kind of... implode. The corresponding novel, by Andy Weir, says he will explode (as pointed out by @...
0
votes
1answer
50 views

Why divide surface area to volume for strength in living beings? [duplicate]

As the title says, why divide surface area to volume for strength in living beings ? I mean why all surface area ? Shouldn't it be area touching the ground ? Thanks in advance! :)
1
vote
0answers
102 views

Why do our eyes only pick up electromagnetic radiation which has been classified as visible light?

My understanding: Electromagnetic radiation is carried via photons - which enter our eyes and activate receptors depending on the amount of energy the photons have when hitting them. At what point do ...
1
vote
2answers
162 views

What are good references for learning about Biophysics at graduate level?

I am graduating this year on both Physics and Mathematics and I want to pursue a career in research, more concretely I want to study Biophysics. I've been recommended Boal's Mechanics of the Cell and ...
0
votes
1answer
66 views

Literature on scientific achievements in physiological acoustics after Helmholtz [closed]

I'm greatly interested in theoretical/mathematical/physiological aspects of music and the corresponding acoustics. As everyone knows, the Greek already discovered that consonant sounds seem to ...
2
votes
1answer
96 views

Soft Condensed Matter book for self study

I'm a junior undergraduate in physics & materials science. I've had half of a course in quantum mechanics taught out of Townsend's book (We've gone from beginnings of matrix mechanics to the ...
0
votes
4answers
145 views

What is the theoretical fastest way a human could be accelerated without dying? [closed]

Humans can survive maybe 3-10 $g$'s sustained acceleration when applied to their backs, like in a rocket launch. This question is not about that. I'm wondering about alternative theoretical future ...
0
votes
1answer
43 views

What is the different between Poisson Nernst–Planck and Poisson Navier–Stokes in the Electrolyte?

I am now studying about electroosmosis flow phenomena which is governing by the Navier-Stokes equation and Poisson equation. By combine these two equation we can describe the electrolyte flow velocity ...
-2
votes
2answers
129 views

Can $CO_2$ be separated into $C$ and $ O_2$?

I'm doing a little bit of research for an experiment that I want to conduct in science and it relies on that one question. So, Is it possible to separate a $CO_2$ molecule into a $C$ and $O_2$? ...
0
votes
1answer
45 views

Correcting Myopia with a Diverging Lens

My textbook says that a diverging lens works by rendering the object a virtual image at the myopic eye’s far point. However, wouldn’t the eye then perceive an object farther than its far point at the ...
0
votes
1answer
85 views

Change of internal energy to kinetic energy

Why do we feel tired while running as during running we are increasing our kinetic energy. I understand that the energy inside us(from food or something else) is being converted to KE while running ...
0
votes
1answer
127 views

Energy/entropy in transport of molecules across cell membranes

I'm asking a "Maxwell's Demon" question. I've read statements that sorting molecules and sending them to one side or the other of a barrier requires work, but none of these statements have explained ...
1
vote
2answers
55 views

What is the physical interpretation of Power Spectral Density (PSD) in optical tweezer?

For the calibration of an optical tweezer, the PSD of position values are plotted. If it follows a certain behavior having two regions - free diffusion and potential limited regions, then the trap is ...
0
votes
0answers
22 views

Hiccup in frequency domain

Main question: What would the Fourier transform of hiccup look like? This question is too general so let me elaborate a few possible approaches. Hiccup just as a series of pulses (of no matter what ...
0
votes
0answers
24 views

Electric dipole moment of a coaxial cable?

Question Does a cylindrical coaxial cable have a net electric dipole moment, and if so why? Context I am trying to understand why the heart has a net electric dipole moment. In the heart we have ...
0
votes
1answer
46 views

Plausibility of the distance estimation in a cycle ergometer gym exercise

A friend of mine pedaled for an hour on a cycle ergometer, a stationary bicycle in a gym. At the end of the ride the cycle computer reported a distance of $40\:\mathrm{km}$ and an average power of $...
0
votes
1answer
43 views

Infrared light and heat

I know that mid wave IR, long wave IR, and far IR are all infrared light that we feel as heat. Often, even when it is cold and windy, if I face the sun in a sunny spot it feels like it is 80 degrees F ...
1
vote
1answer
131 views

How much work can the human body do before dying of exhaustion [closed]

If we could assume: We don't increase our energy from absorbing food. Our human example in scope isn't starving or suffering from malnutrition. I mean how much work can we do until the body would ...
2
votes
0answers
204 views

Is WiFi safe for humans? [closed]

I have WiFi on at my home almost all the time. I learned that the frequency of visible light is around several hundreds of THz, while the frequency of wifi is only several GHz, which is only 1:100,000....
1
vote
0answers
39 views

Biological concept behind time dilation [duplicate]

What is the exact mechanism which makes aging process slow for persons travelling at higher velocity relatively. How does our body cells responds to gravity and undergo aging?
2
votes
2answers
675 views

Measuring energy when no work is done — comparing push-ups to planks

tl;dr Is there any meaningful (physical) way to compare the energy expended in the exercise of doing $x$ pushups in $t_1$ seconds, vs the exercise of doing the plank for $t_2$ seconds? I'm ...
1
vote
1answer
57 views

Relation of Force and Energy, from a biophysics point of view

Considering us humans practically, does energy require force, ie we do apply some internal and external forces to do work, or does force require energy. ie we can only apply a force on an object if we ...
-2
votes
1answer
104 views

Why is thinking not considered as work? [closed]

While thinking the impulse in our neurons displace and they move in direction of force applied on them. Here the force is applied and impulse moves in direction of force ie it is displaced. Then, why ...
0
votes
2answers
91 views
1
vote
1answer
72 views

Is (or why isn't) static charge as lethal as ionizing radiation?

Ionizing radiation, e.g. the "stuff" emitted by radioactive materials, is dangerous to humans since changes to the electron configurations (in the human body) causes the various molecules (in the ...
3
votes
3answers
182 views

What would be the minimum size of a planet which would allow a human being to walk around without falling out in the open space?

On the Earth you can walk - of course we all know it - in the southern hemisphere without falling out in the open space, and you feel no difference between being at the North Pole or on the Equator. ...
1
vote
0answers
14 views

Fluid motion videos [duplicate]

I am looking for references to papers and research problems involving fluid mechanics, and in particular animal/plant/bacteria locomotion, that could be illustrated by showing a video like these. It's ...
0
votes
1answer
382 views

Are muscle cells electric dipoles?

I'm wondering how we can detect the electrical activity of a muscle cell. My initial thought on this question was that the membrane potential, around $\Delta V_{\text{membrane}} = -80mV$ across the ...
2
votes
0answers
95 views

Can you be your own space suit? [closed]

A few days ago a question was asked on Reddit whether or not a human could survive in space with "just enough" of a spacesuit to plug all the important holes, e.g. a face mask to plug the eyes, ears, ...
4
votes
1answer
786 views

What exactly happens to an exposed human body in space?

I know that space is a vacuum, has no air, and is very, very cold. From what I have seen in movies and TV shows when a space suit is exposed the oxygen will escape like a visible gas and the person ...
0
votes
1answer
97 views

What is the real definition of entropy? [duplicate]

In our bio class our teacher told us that entropy was the amount of heat lost by a system. But I had learned before that entropy was like chaos / disorder in a closed system. Which definition Is right,...
2
votes
1answer
422 views

Would there be EMF induced in our body due to electromagnetic radiations?

The experiments of innovative Faraday and Joseph Henry in USA, conducted around 1830, demonstrated conclusively that electric currents were induced in closed coils when subjected to changing magnetic ...
0
votes
1answer
44 views

Missing causal correlation between distant parts in the brain [closed]

The Wikipage on the Primary Motor Cortex says: Evarts suggested that each neuron in the motor cortex contributes to the force in a muscle. As the neuron becomes active, it sends a signal to ..., ...
1
vote
1answer
94 views

Why the visual system does not affect by the quantum zeno effect?

According to the quantum zeno effect, if a measurement is done on a sufficiently high frequency, the system remains stationary. In daily life, human see objects are moving. (i) Is the procedure ...
0
votes
2answers
127 views

What would be the dose rate of 109 grams of uranium per day/year?

I know that with a Pancake probe that can read alpha you can get up to 30K CPM on a small plate. I ordered a 6" red plate off ebay and measured outside the box when it came in. It registered around ...
1
vote
2answers
62 views

Can we trap living cells in optical tweezers?

I read that optical tweezers work on the principle of radiation pressure caused due to momentum change of incident light due to refraction from a spherical object. For refraction to happen the object ...
17
votes
6answers
15k views

Google interview riddle and scaling arguments

I am puzzled by a riddle to which I have been told the answer and I have loads of difficulties to believe in the result. The riddle goes as follows: "imagine you are shrunk to the size of a coin (i....
0
votes
1answer
58 views

Questions regarding Vacuum in space [duplicate]

The mention of vacuum has always created questions in my mind. In space isn't there near complete vacuum. If there is then why don't the oxygen travel from the suit to space (because of large ...
0
votes
1answer
116 views

Measuring friction coefficient with a inclined plane. Beetle problem

I want to measure friction coefficient between a beetle and an inclined plane (angle of inclination $\theta$). As we all know, friction coefficient $\mu$ is given with: $\mu=tg \rho$, where $\rho$ is ...
-3
votes
1answer
422 views

Double slit: Does human attention, such as meditation change the outcomes of the double slit experiment [closed]

From Dean Radin's article published in Physics Essays, the abstract states: Abstract: A double-slit optical system was used to test the possible role of consciousness in the collapse of the quantum ...
1
vote
3answers
2k views

Do we know if the human brain follows Moore's Law? [closed]

EDIT This question is extremely badly worded and I would appreciate it if you could ignore it's content. I cut and pasted parts of two related but unfortunately distinctly different questions into ...
1
vote
3answers
661 views

Was the early Earth radioactive?

I've been reading of the (surprising) fact we are uncertain on whether there is nuclear fission in the center of the Earth or not (yet we know so much detail on structures at the other end of the ...
0
votes
2answers
77 views

What law of physics did these people think they disproved?

I was trying to understand the Physics of how water gets to the leaves of a tree and found this article which claims some experiment disproved a 300 year old law of Physics. Sounds pretty unlikely... ...
-1
votes
1answer
143 views

Tough mudder “Electroshock therapy” obstacle [closed]

The Tough mudder is an obstacle race where some obstacles test someone's mental grit. One of the obstacles is the "Electroshock therapy" where someone has to run through dangling wires that carry ...
0
votes
0answers
56 views

Confusion regarding interpretation of a diffusion related PDE?

So I was reading Keller & Segel paper related to mathematical model of cellular aggregation in slime molds. In the model (considering 2D assumption) we have an equation like below: $\frac{\...
0
votes
1answer
49 views

An impossible relationship between variables

This book chapter defines $CV$ as follows: $$ CV^2 = 2\pi\nu^2\int^\frac{V_{th}-V_{ss}}{\sigma_V}_\frac{V_{r}-V_{ss}}{\sigma_V}dxe^{x^2}\int^x_{-\inf}dye^{y^2}(1 + erf(y)) $$ However, Figure 15.2 in ...