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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12
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2answers
742 views

Does energy expenditure require movement? [duplicate]

In every formula I've seen that involves energy, I've also seen a distance element. Is there nothing that doesn't involve movement? For instance if I hold my arm out parallel to the ground with a ...
20
votes
2answers
5k views

How does space affect the human body (no space suit, no space craft)

How does "outer space" affect the human body? Some movies show it as the body exploding, imploding or even freezing solid. I know space is essentially a vacuum with 0 pressure and the dispersion of ...
3
votes
2answers
13k views

Does staring at a bright LED light damage your eyes?

According to this article it seems that it is the UV part of the spectrum from the Sun that causes damage to the eye. Would it therefore be "safe" to observe directly an equivalent energy density LED ...
0
votes
0answers
32 views

Chromatic aberration in human eye [duplicate]

A lens focuses the different colours of white light at different points. Since our eye has a convex lens there should also be such an aberration but we see objects clearly with normal eye. I want to ...
0
votes
1answer
520 views

What would happen to the human body if we went almost at the speed of light? [duplicate]

If we were to travel almost at $299\,792\,458~m/s$, or the speed of light, what would happen to the human body? Would the human body stay the same or would there be consequences that would harm the ...
6
votes
0answers
246 views

Does this method of predicting the ratio of translational diffusion coefficients for a sphere and a sheet, work?

Imagine that I have a spherical particle of molecular weight $M$, volume $V$, and some experimentally observed center-of-mobility translational diffusion coefficient $D_{sphere}$ in water. I take ...
12
votes
1answer
4k views

Can microwaves affect WiFi?

I listen to the radio via my iPad with wifi. When I switch the microwave oven on, the radio cuts out. When the microwave oven is finished, the radio comes back on. (This is 100% reproducible!) So - ...
0
votes
1answer
133 views

What happens when a bird lands on a power line?

I know that when a bird is sitting on a high-voltage power line, virtually no current flows through the bird because there is (almost) no voltage drop between its legs, the two points are ...
-2
votes
3answers
165 views

If radiation didn't exist, would everything live longer? [closed]

I recently noticed that dying of old age is similar to a death by radiation - hair loss, weakened immune system etc. and I was wondering - Does background radiation limit our lifespan, or that of any ...
-1
votes
2answers
374 views

Why do we (3 dimensional creatures) see in 2 spatial dimensions? [closed]

Why do us humans, as 3-dimensional (in terms of space) creatures, see everything in 2 dimensions? Is it because the surface of every 3-dimensional object is 2 dimensional? Or because light enters our ...
0
votes
4answers
231 views

Is the hard problem of consciousness an obstacle to finding a physical theory of everything? Why or why not?

I do not understand how, without understanding the mind and how (physical) neural interactions within the brain give rise to consciousness, one can have a definitive theory of everything. There will ...
2
votes
0answers
66 views

Understanding quantum coherence in biological processes (Magnetoreception)

Moved my questions to the top. Context below. Why is the strength of the electric field and the coupling constant being compared to the inverse coherence time? What is the inverse coherence time? Is ...
1
vote
1answer
99 views

Kettlebell squats center of mass

I should, first of all, state that I have very limited knowledge of physics but as a fitness enthusiast the following question has puzzled me for a while. When I do squats on the gym holding a ...
62
votes
3answers
107k views

Why can Hiroshima be inhabited when Chernobyl cannot?

There was an atomic bomb dropped in Hiroshima, but today there are residents in Hiroshima. However, in Chernobyl, where there was a nuclear reactor meltdown, there are no residents living today (or ...
18
votes
1answer
1k views

How long would it take for a smelly object to evaporate?

This question is a follow on from this deleted one: http://physics.stackexchange.com/q/177894/26076 as I was writing what I thought to be a valid physics answer to it. Version 1 of this question ...
0
votes
2answers
87 views

How can plants rooted on the ground become charged?

According to a quote on the physics forum "Plants are usually charged negatively and emit weak electric fields." Reference However this seems to contradict the fact that plants are grounded and any ...
0
votes
1answer
164 views

Why does the sky look blue rather than violet? [duplicate]

Sky looks blue because because our eyes are sensitive to blue colour. But when viewed through a camera why don't we see violet of the sky even though we can see violet colour of other pictures taken ...
1
vote
2answers
140 views

Singing for physicists: How to resonate by body cavities with my voice?

My body has various cavities, such as my throat, mouth, chest, and nose. This cavities have resonant frequencies. I also have a voice box, which creates sound. How do I create sounds at the resonant ...
0
votes
1answer
75 views

Factors affecting pain of static electricity shock

Referring to How to avoid getting shocked by static electricity?, someone I knew suffered much pain from static electric shocks when touching door knobs or car doors where I didn't feel anything doing ...
12
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2answers
4k views
10
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2answers
1k views

Why is pale coloured skin said to absorb more UV?

Many resources state that light skin/pale skin absorbs more UV than dark-colour skin. Doesn't black absorb maximum radiation? For an example, see this article: Natural selection therefore ...
1
vote
0answers
110 views

Visualise the sound intensity

I'm studying Biophysics and my current subject is sound. One of the properties of sound is intensity. From my notes I can see the following definition: Intensity Formula is: $(I = w*m^{-2})$ or $(I = ...
1
vote
1answer
127 views

Physics involved in the DNA-structure discovery

In 1962 Francis Crick, James Dewey Watson and Maurice Hugh Frederick Wilkins won the Nobel Prize: For their discoveries concerning the molecular structure of nucleic acids and its significance for ...
0
votes
2answers
106 views

Laser tattoo removal

I would like to know if someone could please briefly explain how laser technology of tattoo removal works? And second, could there possibly be any dangers to cells, specially on bones?
5
votes
6answers
1k views

Why do we lift our feet when we walk?

I'm not sure if this is a good question for here- albeit if I asked it somewhere else I'd want the physical argument. Why do we lift our feet when we walk, as opposed to doing something like ...
-1
votes
1answer
66 views

Top speed for a human

What is the fastest that a human being of average weight could possibly travel, and what is the most widely held theory for how this might be achieved (assuming this person is impervious to all forms ...
0
votes
0answers
24 views

Frequency resonance of Bones, and other parts of the human body [duplicate]

Today in class we were learning about states of matter. I found out that in a solid the atoms are vibrating. This caused me to think about how crystal glass will break if an opera singer sings high ...
1
vote
2answers
456 views

Human Muscle Energy - Increases or Decreases by doing work?

When Human does some work, he gets tired. I will think he looses some energy. If he really loses energy by doing work how does he gain more strength to do more work later. His muscles become strong ...
7
votes
4answers
3k views

Can the brain detect the passage of a neutrino?

On a few occasions either in bed or sitting around a fire, with my eyes closed, I rarely but sometimes see a very quick fast flash of white and then, with my eyes still closed, the flash disappears ...
59
votes
3answers
8k views

How can ants carry items much heavier than themselves?

This morning I saw an ant and suddenly a question came to my mind: how do ants actually carry items much heavier than themselves? What's the difference (in physics) between us and them?
5
votes
4answers
344 views

How would swimming in low gravity work?

Sorry I know very little of actual physics, I'm not looking for hard and fast numbers just a general idea of how the mechanics would work. For the sake of argument, say you were on a planet or moon ...
16
votes
4answers
3k views

What does Peter Parkers formula represent?

Okay, so the trailer for the new Spider Man movie is out and appearently our friendly physicist from the neightborhood came up with something. However I can't find out what this is. Transcription: ...
0
votes
4answers
82 views

Using formula for work with distance of 0m [duplicate]

Consider this: Wind is pushing a huge rock towards me at with massive force at 2m/s. I push against the rock at equal force so the rock stays still. I am clearly "working" very hard, using a lot of ...
0
votes
0answers
72 views

Will increased air pressure increase efficiency of solute diffusion into a membrane?

Biophysics question: I have a container with a biological tissue inside of solution where the solute slowly diffuses across the membrane and binds inside of the tissue. If I were to put this unsealed ...
2
votes
2answers
375 views

What are the main issues that are preventing a human mission to Mars? [closed]

Is it just because it'd be very expensive? Or are there serious problems that need to be dealt with, studied and solved? If so, what are they?
0
votes
1answer
34 views

a question regarding Fourier transform in electron microscopy

I have recorded a micrograph of a 2-D array at a magnification of 43,000x on my DE-20 digital camera, which has a 6.4 μm pixel size and a frame size of 5120 × 3840 pixels. This magnification is ...
1
vote
1answer
98 views

Molecular simulation applied to astrobiology

There is some research group which use molecular dynamics simulations to study the origin of life according to the hypothesis of abiogenesis? I'm just beginning to know this subject so I don't know ...
1
vote
3answers
3k views

How do birds generate thrust?

I have been watching this video carefully and I want to know how the wings of birds generate thrust. This is because the wings are more or less flapping up and down --- generating the lift. But I do ...
0
votes
1answer
91 views

What is one human power? [closed]

some time ago I was asked what the HP equivalent of a human was, looking into this apart from in the creation of steam engines the power definition 1 Horse power was set at the work of two of the best ...
0
votes
3answers
84 views

Work power and energy

When you push your bicycle up on an inclined the potential energy of the bicycle and yourself increases. Where does this energy come from?
1
vote
0answers
60 views

How much energy does it take to hold a bag? [duplicate]

I'm holding a bag with some mass $m$. The force required for not letting it fall is equal to its weight $m \cdot g_L$ (where $g_L$ is the local gravity, assuming Earth this is $\approx 9.8 \; \text{m} ...
6
votes
1answer
894 views

Why do I hear a deep rumble when I cover my ears?

Probably a trivial thing but a simple google search didn't show anything relevant about it. If I cover both of my ears with my hands, I hear a very deep rumble. If I slowly move my hands away the ...
2
votes
0answers
125 views

What biology knowledge can be applied in physics? [closed]

After asking a commensurate question in Biology.SE (What physics knowledge can be applied to biology of organisms and ecosystems?), I wonder about the reverse direction: What biology knowledge can be ...
1
vote
1answer
164 views

Polonium tea emergency [closed]

Let's assume that I just realised that tea I drunk 30 minutes ago during meeting with a secret agent was doped with radioactive polonium. What should I do? What the doctors will do? Are there ...
0
votes
1answer
72 views

A parameter to quantify instability in flight

Suppose I have plotted the body angles of a flying aeroplane.I have two such plots. One of a normal plane, and the other plot in which a primary sensor of the aeroplane is removed. So with the absence ...
8
votes
3answers
2k views

How are the calories in food calculated?

This is intended to be a fun question. Calorimetry used for calculating the heat generated from chemical changes has been around for centuries, however, I suspect the process for calculating food ...
9
votes
1answer
1k views

How much does increased world population contribute to global warming?

In 1974 there where 4 billion people on earth. Now in 2013 we passed 7 billion people. So the world population is nearly doubled in 40 years. Every living human being also haves a body temperature of ...
1
vote
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
votes
1answer
208 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 ...
5
votes
3answers
8k 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 ...