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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4answers
2k views

What is our estimated running speed on Moon's surface?

I was wondering if we have the chance to run on the Moon's surface, how would you expect it look like? I expect our velocity will increase for the same work we do on Earth, but not sure if this will ...
-1
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1answer
178 views

Possible dangers of power lines radiation, wi-fi and gsm technology [closed]

I'd like to know more about the topic mentioned in the title. I have 3 questions. I'd be happy to hear your thoughts on any of those. So if high voltage power lines can cause harm to a human in some ...
4
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3answers
6k views

How does blood/saliva boil in outer space?

Why would the blood boil? Is it because of the temperature or pressure? Because I really can't figure it out. I thought space didn't have a temperature above freezing unless close to a star or the ...
18
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8answers
3k views

What's the difference between running up a hill and running up an inclined treadmill?

Clearly there will be differences like air resistance; I'm not interested in that. It seems like you're working against gravity when you're actually running in a way that you're not if you're on a ...
2
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1answer
239 views

Would a six-inch person face certain death when falling from a great height?

In Mary Norton's The Borrowers Aloft, the borrowers are like humans in every way except size - normal adult height is six inches. One family of three is captured by a human couple and housed in an ...
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0answers
79 views

If we increase the aperture of a telescope and decrease its magnification, can it be harmful to the eyes?

The full moon is the brightest object in the night sky. I believe that if we increase the aperture of the objective, and decrease the magnification of the telescope, it might concentrate a dangerous ...
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2answers
227 views

Order of magnitude estimation for some intriguing questions

The physics TA showed us a few examples in which one can estimate many things from first principles, sound logic, and scaling arguments. This led usually to understanding of why some numbers have the ...
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0answers
45 views

Will the usage of Exo-Skeleton Gear actually weaken the human body over time? [closed]

As we all know, Exo Skeletons as they exist now are just a series of Force multiplying apparatuses working together, also the human body changes to accommodate environment specific factors in order to ...
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0answers
58 views

Why are flight feathers asymmetric?

I've always heard that flight feathers were asymmetric because the shape generates lift, like an airplane wing airfoil shape. But, the feathers are not oriented with the shaft perpendicular to the ...
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2answers
2k views

Why human and most of vertebrates cannot see Near-Infrared light (720nm-1500nm)? [closed]

On daytime, the surface of Earth is illuminated abundantly by light of spectrum from 250nm-1500nm, that includes near-ultraviolet spectrum (250nm-380nm), visible spectrum (380nm-720nm) and ...
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3answers
648 views

Do mobile phones produce radiation harmful to humans? [closed]

What are the health effects of mobile phone radiation (if any)? Does using a mobile phone without an SIM card change the answer?
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2answers
121 views

What's Optimal About Six Legs According to Physical Laws? [closed]

In many respects the insects can be regarded as the most successful class of animals in evolutionary terms. And one of the most common features of insects is that they (mostly) all have six legs. Not ...
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4answers
2k views

The physical definition of work seems paradoxical

So this is possibly a misunderstanding of the meaning of work, but all the Physics texts, sites, and wiki that I've read don't clear this up for me: In the simplest case with the simplest statement, ...
2
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1answer
92 views

What is the physical clock ticking inside a living cell? [closed]

What is the physical process which determines the timescale of the aging of a living cell? It might be that on the macroscopic scale, i.e., aging of the human, the gravitational force is one factor ...
2
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4answers
585 views

What was the motivation behind suggesting the trichromatic theory of vision?

Background In this thread, I asked whether it is true that the colors red, green and blue, through additive mixture, can make up any color. Turns out they can't. However, when reading about the ...
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2answers
88 views

How do we represent 'smell' and 'taste' as signals?

I was wondering if we could represent 'smell' and 'taste' as signals like we do for audio. How do we mathematically represent them? Is there any research papers related to it? Can someone give me ...
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2answers
64 views

Brain and UV rays [closed]

I heard that brain can be switched off using ultra violet rays. I seek experts comments on this. Is it true? If it is so how it is possible to control brain by UV rays?
2
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0answers
87 views

How does the Darma - Smart Cushion work? Explanation of the new fiber loop ring-down spectroscopy

How does the Darma - Smart cushion monitor your sitting position and obtain the breathing rate, body movements, and BCG (Ballistocardiography) signals? The creators say that they accomplish this by ...
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3answers
243 views

How much further can I throw a baseball (148 grams) than a grenade (453 grams)?

Question: Over a flat plane, how much further can I throw a Major League baseball than I can an M67 grenade? Major League baseball: 148 grams M67 frag grenade: 453 grams For a baseline of how ...
2
votes
1answer
181 views

Biophysics and mathematical biology landmark papers [closed]

I am PhD student in biophysics, and I am looking for interesting theoretical papers for my personal training and for journal club presentations. Going on journal websites and browse the thousands of ...
1
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1answer
44 views

Is electricity constant in standard ECG device? [closed]

I am reading the book Bioelectromagnetism by Malmivuo et al. I am thinking if you need to use Maxwell equations in electromagnetism of ECG device. I am not sure if you need to change the current ...
1
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0answers
31 views

The needs of photonic senseor for biomedical applications

I am doing a literature review on the topic mentioned in the title. When I write the review, I found myself a contradiction. Just want to listen to opinions from others :P Nowadays, the development ...
3
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0answers
298 views

Nobel prize for (dangerous) LED lamps? [closed]

There are many scientific articles about the danger of LED lamps (see below from the LED magazine, from scientific american, from a governmental journal and from Harvard health newsletter): Light ...
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2answers
4k views

How strong of magnetic field would noticibly attract a person?

There is Iron in blood. Iron is magnetic. Roughly how strong would a magnet have to be to induce a noticeable attraction? It would be nice to know this for several distances. Also, do electromagnets ...
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0answers
26 views

Magnetic field of a living human [duplicate]

Is it true that a human body is like a bar magnet? Say our head is north pole while the legs are south pole, or vice versa? If so, can we confirm it by experiment say with the 360 Pro compass etc?
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1answer
276 views

Why does an electric field oppose the flow of positive ion?

I'm solving a very interesting problem. Suppose a cell is divided into inside and outside. Inside we have positive ions and outside we also have positive ions in different concentration. Suppose ...
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2answers
280 views

Is Water the only Liquid of Life? [closed]

What makes scientists think that water is better at sustaining life than every other substance? every organism we know of needs water to survive. In fact, without water, life on Earth would have ...
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0answers
33 views

Matter and Electrical Impulses

The human brain is composed of about 100 billion neurons; with trillions of synapses. These synapses transmit signals, which is obviously made of some sort of matter. This is what creates thought and ...
4
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3answers
334 views

How to calculate when wheels are better than legs?

We all know that it uses less energy to go by wheeled transport than walking if the terrain is smooth and there are not too many hills. We also all know that when going up steep hills we get off ...
3
votes
2answers
486 views

How much work will a human do to lift a weight?

I saw a pretty simple homework question here that asked how much work it takes to lift a 200 kg weight, and while the math for a basic answer is simple the weightlifter in me instead wanted to ...
46
votes
7answers
7k views

Cyclist's electrical tingling under power lines

It's been happening to me for years. I finally decided to ask users who are better with "practical physics" when I was told that my experience – that I am going to describe momentarily – prove that I ...
2
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1answer
64 views

Electromagnetic fields and human behaviour

To what extent does electromagnetic fields and/or radiation from space have influence on human behaviour and/or physiology?
3
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1answer
671 views

How muscle force work? [closed]

If muscle works with force on joint and joint works with exact force on muscle(newton III law) how can muscle drag much heavier weight than itself?
7
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1answer
1k views

Do we breathe air by creating a vacuum?

How do we suck air into our lungs, are we generating a vacuum?
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0answers
44 views

dose physics affectthe biological like this [closed]

According to neural sciences the brain process information and reacts in 1 teen of a seconds the numbers add up to be 10.596674 loest is 30 to 20 years the course of time in reality recorded by our ...
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0answers
69 views

Validity of a steady state solution of reaction-diffusion equation

I am performing a simulation involving growth of bacteria. This is an agent-based simulation where the solutes (glucose, oxygen etc.) are represented as a concentration field discretised over space, ...
0
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3answers
298 views

How to generate Red light from a Blue-Dominated Spectrum [closed]

I have a white LED light source, the spectrum of which looks as follows --- I want to filter out red light from this white LED source. But as you can see the spectrum dwindles in the red zone. And ...
0
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1answer
176 views

How do you calculate the power needed to keep something stationary? [duplicate]

1) If I place an object on a table, it will sit there forever. There's no change in potential or kinetic energy. If I hold the object at the end of my outstretched arm, eventually I can't do it ...
0
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0answers
66 views

The mathematical physics of saltatory neuron action potential transmission

Some time ago, I tried to understand saltatory electrical potential transmission on a myelinated axon but have not found a clear mathematical model of this mechanism. I understand the cable theory, ...
2
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0answers
60 views

What happens to proteins under x ray/gamma ray radiation?

A simple question to which I am yet to find an answer. I have not found any papers which would go into detail about it, there is some stuff on protein damage in x-ray crystallography but they are ...
0
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1answer
75 views

What are some publications which continue Schrödinger's “What is life?” discussion?

I'm looking for modern publications on the physical nature of life in which the primary reference is to the discussion started by Schrödinger in 1944 in his book "What is life". For example, ...
1
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1answer
52 views

Why is work not related to velocity?

A very simple question; why does it cost me more energy to very slowly lift a mass $m$ over my head compared to very fast? The definition of work does not state anything about velocity, only the ...
66
votes
8answers
17k views

Why does holding something up cost energy while no work is being done?

I read the definition of work as $$W ~=~ \vec{F} \cdot \vec{d}$$ $$\text{ Work = (Force) $\cdot$ (Distance)}.$$ If a book is there on the table, no work is done as no distance is covered. If I ...
6
votes
1answer
702 views

``What is life?'' by a physicist definition [closed]

The question is about defining ``What is life?'' in the field of Physics. Whether there is any (insightful) way of defining ``What is life?'' from physicists. There are pioneer works, including ...
2
votes
1answer
179 views

Walking & Swinging

How can I show that the most convenient way to move the arms while walking is swinging them back and forth, alternatively? To pose the question in another way: can I prove, starting from the ...
3
votes
0answers
144 views

Fluctuation spectrum of lipid bilayer membranes

I am interestend in calculating the fluctuation spectrum of a thermally fluctuating 2d membane which is only subject to a surface tension $\sigma$. ($\mathcal{H}=\sigma\int\mathrm{d}A$) Depending in ...
3
votes
1answer
4k views

How to calculate calorie expidenture from lifting a weight?

Am I correct to say that when a human lifts a dumbbell from, say, 2 feet off the ground to 6 feet off the ground, he will have increased the potential energy of the weight and thus will have burned ...
5
votes
2answers
1k views

Frequency of touch, taste, and scent [closed]

So I was thinking about sound - and how anything below 20Hz is basically inaudible to humans (because it is too low of a frequency to be recognized), as well as anything above around 20KHz (because it ...
2
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3answers
695 views

Electric impluses inside nerve cells

I'm not a biologist, nor physicist, but there is one thing I try to understand about the elecricity inside human body. I wasn't sure whether place this question here, or perhaps on biology portal, but ...