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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Decompression sickness

In decompression sickness why does nitrogen gas come out as bubbles? Is it because under high pressure the nitrogen gas was converted into liquid nitrogen and during the process of coming to the ...
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1answer
47 views

Confusion over plant's “magnetic field” being used to reduce wastage of pesticide

As far as I am aware, a plant does not have a magnetic field of any significant magnitude. What I wonder is, is there any electromagnetic related basis for the crop spraying technique outlined in ...
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1answer
36 views

Is it possible to fight tree height limit with centrifugal force?

I heard tree has some height limit because water cannot be pumped over some height (130m if I remember it right) which cap the limit of tallest tree possible on earth But there are centrifugal force ...
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4answers
5k views

Why does adding red light with blue light give purple light?

Our eyes contain 3 photoreceptor cells (cones) to perceive three wavelength ranges of light. Here is a visual representation of the wavelengths by these receptors (S, M and L). So if we have light ...
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1answer
47 views

How to shield myself from the LTE radiation coming from my phone while working on my Laptop? [closed]

I am connecting to the internet with the tethering option on my phone. I wonder if there is a way to shield myself from the LTE radiation (Long-Term Evolution, commonly marketed as 4G) as I am exposed ...
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1answer
55 views

Physiological Significance of Superposition

To what extent is the concept of superposition appropriate to physiology? In other words, can organisms "actually" exist in a state of superposition?
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3answers
17k views

Does the human body have a resonant frequency? If so, how strong is it?

Inspired by this question on Music beta SE, I'm wondering if the human body has a strong resonant frequency. I guess the fact that it's largely a bag of jelly would add a lot of damping to the system, ...
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0answers
17 views

Can we define a whole body thermodynamic model for human?

we can consider human body as a thermodynamic system and an energy exchange system, so we can investigate efficiency, entropy, exergy, is there any thermodynamic model for whole body?
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1answer
40 views

How much ionizing (carcinogenic) radiation is one exposed to on a commercial flight, what are the sources, and how could exposure be minimized? [closed]

I don't know if this is the best place to ask this question, but I figure a physics-based answer would be the most satisfying. I'd be happy to be convinced I'm being paranoid about protecting an ...
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0answers
35 views

Why does the lack of pressure in outer space affect what's inside our bodies?

I have read multiple similar questions on this site, but none answer specifically the thing I am having trouble understanding. I have read repeatedly that a lack of pressure will cause the fluids ...
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1answer
34 views

Voltage homogeneity across cell membrane

During respiration, individual cells produce a relatively large potential difference ($\sim 100$ mV) between the inside and outside, using energy to pump $H^+$ out of the cell to the liquid ...
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2answers
75 views

Why is it harder to situp on solid floor?

When I situp on solid floor it is harder for me to lift my body upwards versus on a soft/foamy floor which I can do a lot.
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1answer
60 views

If a being was able to swallow itself, where would it go physically? [closed]

if a being was made from a special type of material that allowed it to stretch and was very flexible, if it were to swallow itself, where wold it go. I mean the physical aspects of it since it wont be ...
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2answers
160 views

Fired a bullet upwards, can it fall down and kill me?

I know that if something is thrown up with a velocity v, it comes down with the same velocity as long as its motion faces no resistance. So is it possible for me to fire a bullet and be killed if it ...
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3answers
76 views

Lifting and putting down a weight

A man in a gym lifts a weight and then puts it down where it was before. 1) What can be say about the work done by the man to the weight? 2) Can it be equal in absolute value to the work made by ...
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1answer
12 views

how does voltage sensitive dye determine the membrane potential?

There are so many papers about VSDs and how to use them, but i can not find anything about what exactly is happening in the cell membrane that leads to the change in VSD's light intensity as a sign of ...
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1answer
153 views

The difference in how temperature feels inside in the summer vs. in the winter?

72 degrees feels cooler when it's hotter outside, say 90 F but warmer if it's really cold outside, say 32F However it also feels different if it's 90 vs say 70F outside. Why is that?
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0answers
16 views

Bimolecular and Isomerization reactions

Is it possible to describe a reaction of the $$ A+B \rightleftharpoons AB $$ exactly using the solution of an isomerization reaction? $$A \rightleftharpoons B$$ I just can not figure it out the ...
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3answers
52 views

According to the second law of thermodynamics, would life be possible on an Earth always facing the sun?

Suppose the Earth was making one complete rotation around its polar axis every year. Will life develop, or will there be a constant flow of energy from the Sun through and around the Earth? Will a ...
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2answers
83 views

Do animals defy gravity? [closed]

I am a beginner and trying to understand the concept of gravity Do animals defy gravity? If yes, which animal defies and in what way it does? Sorry had I asked something wrong
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2answers
60 views

Why was it difficult to walk in the same direction the train's acceleration, and easier the other way around?

The other day while I was walking in the same direction that the train was accelerating. Then I came across this question. Please if would answer it, I am very curious to know. But when I walked the ...
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2answers
275 views

How much more “work” (or energy) is required for short people to hike uphill?

Let's assume Short Person is 5 feet tall and the Normal Person is 5 feet and 8 inches tall. Let's assume the uphill hike has steps with 1 foot height. How much more work or energy does this require ...
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4answers
217 views

Does Free Will Theorem imply that quantum mechanics plays crucial role in our brain’s functioning (consciousness)?

Does Free Will Theorem imply that quantum mechanics plays crucial role in our brain’s functioning (consciousness)? Is opposite statement of Free Will Theorem right: If elementary particles have a ...
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0answers
30 views

What is the direction and orientation of the modulation frequency in AM when it uncouples in flesh? [closed]

Cancer research shows that dividing cancer cells could be killed with frequencies from 100 kHz to 300 kHz (Kirson Tumor Treating Fields or TFF). The early research used a monofrequency that was ...
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0answers
47 views

Deriving an upper limit to the information in a human brain

For this question I am presuming that the human brain works deterministically and all information in a human brain is, once you get down to the lowest level, stored through the arrangement and other ...
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2answers
448 views

Space-time hospitality

Are there any reasons to assume that organic processes cannot arise in relatively flat spacetime environments? An argument for the existence of a critial value or window.
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0answers
51 views

What happens at the point of welding iron?

What is the physics behind welding iron? It is obviously the electricity that causes the two metal parts to fuse but what is the role of the welding rod and why is it said to damage your eyes when you ...
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8answers
6k views

Does quantum mechanics play a role in the brain?

I'm interested in whether the scale of processes that occur in the brain is small enough to be affected by quantum mechanics. For instance, we ignore quantum mechanics when we analyze a game of tennis ...
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1answer
63 views

How do snails avoid being cut while crawling over a razor blade? [closed]

This YouTube video shows a snail crawling over the edge of a razor blade without being harmed. The author claims that: To us, slug and snail slime is gooey and gross but the mucus is one of ...
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0answers
40 views

Stability of plants and buildings: the role of the xylem

Dicotyledon plants show a stem structure with many xylem tubes, hollow but with lignified (woody) walls. These are arranged as in the figure below, in a circle. Their roots, on the other hand, have ...
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0answers
21 views

Hydraulic conductivity and flow rate

I have several sources that have the following equation relating the change of volume in a cell to the hydraulic conductivity (permeability coefficient) $L$ and pressure differential $\Delta P$: $$ ...
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1answer
68 views

Can a high-watt laser's scattering light be damaging to the eyes? [closed]

Heyo, I recently purchased a S3 Arctic Class IV laser pointer. I bought the 3500mW. (In case that page expires, it's 445nm wavelength, 1.5mRad variant, NOHD is 279m, beam distance at 0.25 Lux 72km.) ...
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3answers
838 views

How is a human voice unique? [closed]

Well, I am quite new to concepts of vocal sounds. From the physics point of view I believe a sound has two basic parameters i.e, frequency and amplitude. Considering the end sound wave produced by ...
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4answers
453 views

Can we see sound with our eyes? [closed]

Is there a type of sound within our visual spectrum that we can see with our eyes?
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1answer
43 views

Change of energy into friction?

If I am pushing a car and it does not move, I am doing no mechanical work. However, I am changing the energy that was stored in my cells into heat energy (maybe sound energy if my hand slips off the ...
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8answers
14k views

Short of collision, can gravity itself kill you?

Imagine that you are falling into object with huge gravity (i.e. black hole) that does not have any atmosphere. The question is - before you hit the ground, can the gravity itself (which would be ...
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1answer
23 views

Is the range of frequency we hear dependent on the natural frequency of our ear?

Is the range of frequency we hear dependent on the natural frequency of our ear? (i guess the question is clear enough. Just writing to meet "quality standards".)
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1answer
25 views

What parameters could be considered to measure the coiling of a ring?

I want to draw a phase diagram to quantify the coiling of a ring inside my system and I was wondering what parameters could be use to precisely define how coiled the ring is. Currently I am modeling ...
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0answers
35 views

Why do the vines change their spinning direction? [closed]

Look at the vines holding onto the lattice. The "vine springs" change their spinning direction in the middle. Why? And how do they achieve this? (I notice that some vines fail to get in touch ...
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4answers
19k views
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0answers
19 views

How does it takes to deadlift a sports car? [duplicate]

In the movie Furious 7, Dom lift a Lykan HyperSport with bare hands. Given that in reality, how strong it has to be to lift a Lykan HyperSport(1,380 kg), says to 40 cm in one rear end, and hold it ...
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1answer
67 views

If the Earth were a pool ball, could I feel mountains? [closed]

If the earth (12,742 km diameter) were scaled down to the size of a pool ball (61mm diameter), the mountain ranges would still exist, obviously. But would a typical human be able to feel those ...
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1answer
59 views

A sound that always seems to come from behind you

Many years ago I heard a radio broadcast featuring a beeping sound that always seemed to come from behind me. The announcer said that the sound would have this quality and it did, even when I turned ...
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1answer
65 views

Cesium-137 From Fukushima Meltdown

I've been reading up on the Fukushima nuclear meltdown and its effects it had on the environment. The iodine-131 initially released from the incident decayed after 8 days, but other isotopes such as ...
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1answer
48 views

Could we recognise if time was running at a different rate for one species than another? I.e a human and an ant

My question is quite simple if time ran at a different speed for smaller creatures, how would we be able to observe this or confirm by experiment?
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3answers
104 views

The second law of thermodynamics and life on Earth [closed]

The second law of thermodynamics says that order always decreases in a system. The appeareance of life seems to contradict that law, but if we invoke the Sun, everything faals into place again. But ...
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2answers
86 views

Does human body have a centre of mass?

According to this site, The center of mass of the human body depends on the gender and the position of the limbs. In a standing posture, it is typically about 10 cm lower than the navel, near the ...
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2answers
95 views

Safety of Polonium Isotope source

I saw a YouTube video by a guy demonstrating Geiger Counter use and one of his radioactive test sources was a disk with Polonium. He casually mentioned that this was the poison used to kill that ...
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4answers
371 views

Would a neutrino bomb do anything? Or can weak force kill you?

In a disreputable animated cartoon (I accidentally watch every episode of religiously), a mad scientist plans on killing all humans with a Neutrino bomb. From context, this is a bomb that produces a ...
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1answer
89 views

Why do we hear the square of the wave?

Assume we superpose two waves of frequencies $\omega_1, \omega_2$. Then what we get are beats. Adding the two sines gives us $$\psi = A\sin(\omega_1 t) + A\sin(\omega_2 t) = 2 \sin ...