Questions tagged [biology]

Questions about biology are OFF TOPIC and should be asked on the Biology Stack Exchange. However, questions about biology in the context of physics (e.g., biophysics) can be on topic here if the primary concern is physics.

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67
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8answers
11k views

When I walk down the stairs where does my potential energy go?

When I leave my room I walk down three flights of stairs releasing about 7kJ of potential energy. Where does it go? Is it all getting dispersed into heat and sound? Is that heat being generated at the ...
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1answer
70 views

Does brain activity generate anything outside our bodies? [closed]

I have been reading recently about the Law of Attraction and while I don't believe in its 'scientifical' basis it did make me think about whether our brain produces any kind of activity strictly ...
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5answers
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If I touch the “+” side of a high voltage battery, will I get shocked?

Voltage is electrical potential difference between two points. When these two points are connected using a conducting material, current flows. So far so good? Let's think of a high voltage battery (I ...
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2answers
70 views

What would you do to protect yourself from phone radiations? [closed]

It's object of debate whether cell phones' radiations cause cancer after prolonged use, specially when the phone emits at its maximum power and it is closely attached to the body. Like for example I ...
0
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1answer
77 views

Why do ants feel more difficult to climb when height increases?

I have noticed that whenever an ant (carrying something) climbs a vertical wall, it easily climbs the lower part of the wall but as the height increases, the ant finds it difficult to climb and at ...
3
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0answers
38 views

Why does the sun not burn your retinas when in peripheral vision?

After going to the ophthalmologist and having bright lights shone in my eyes, I was thinking about how the brightness only hurts when I looked at the light. When it was in my peripheral vision, it ...
0
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1answer
42 views

Understanding Newton's third law of motion

So recently I learned about Newton's third law. My professor told that if I go to a fight with a sumo wrestler and sumo wrestler punches me with a force of 5000N in my stomach , My stomach also pushes ...
1
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2answers
46 views

Why does closing someone's eyes not give them near-sightedness? [closed]

When we close our eyes aren't we technically looking a really close up piece of skin? That is, our eyelids? If it's so close to our eyes why doesn't it give us bad vision? We know if screens or books ...
4
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5answers
250 views

Do you really die if spaghettified by a back hole?

Considering gravity acts by stretching spacetime and all forces (EM, nuclear etc...) are relative to spacetime, can we then consider that regardless of how stretched you are to an observer outside the ...
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1answer
100 views

Are there physical reasons for breaking this symmetry in biological systems?

For some reasons, it seems that particular "handedness" are chosen by nature, because we have the prevalence of some enantiomer, that have different optical properties respect to ...
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2answers
109 views

What are the implications of deterministic chaos: useful or detrimental? [closed]

I am new to the concept of chaos theory and as a layman I am struggling to understand what is the significance and implication of chaos in ecological systems such as the chaotic predator prey model. I ...
0
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0answers
54 views

Is biology affected by gravity?

I have a question about time. Let's be hypothetical. Let's assume that we have 2 persons in separated parts of the Universe. One is on Earth, and the other one is on a planet on another side of the ...
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1answer
38 views

What are the technological limitations of DNA computing? [closed]

IBM and Microsoft are studying the application of DNA computing, but I was wondering what are the technological limitations that prevent it from being used in the same way as a conventional digital ...
1
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1answer
56 views

Are there any objects that are transparent to humans but opaque to cats and vice-versa? [closed]

What makes an object transparent or opaque is complicated as far as I know but depends on which wavelengths the observer can see. Since cats can see different wavelengths than us humans, are there ...
4
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5answers
376 views

Is limited computational capacity a fundamental obstacle?

Statistical physics books often motivate the necessity of statistical/thermodynamic description by impossibility of calculating the trajectories of all the molecules (I speak of "trajectories&...
37
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12answers
6k views

Does physics explain why the laws and behaviors observed in biology are as they are?

Does physics explain why the laws and behaviors observed in biology are as they are? I feel like biology and physics are completely separate and although physics determine what's possible in biology, ...
2
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2answers
73 views

How does the growing up of trees works with respect to energy conservation?

We know that the energy (and hence mass) can neither be created nor destroyed. In the light of above statement, I would like to understand views on growing up of fauna and flora on earth. A small seed ...
1
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1answer
61 views

Why Shortest Football Players are more agiles than Tallest Player. There are Physical Reasons? [closed]

I mean agile able to make sudden turns, stops, change directions easily and faster, and starts more easily. How many physics laws plays pros and cons in football dynamics?
0
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1answer
34 views

How to calculating the work done / energy consumed by a system?

So I have a question that is, minimise the net energy used for a human on the journey between A and B. Assume the human is 70kg and the distance is around 10km. Assume it is all horizontal. I have ...
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0answers
36 views

Can direct current split $\rm NaCl$ in your body into Sodium and Chlorine?

We can split Sodium Chloride into Sodium and Chlorine through electrolysis by passing a current through the solution. But what if we were accidentally letting a Direct Current flow through our body, ...
4
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1answer
53 views

Does it take more force to travel up the stairs or to travel up the slope next to it? [closed]

The answer might depend on numerous factors (steepness of steps, steepness of stairs etc.) Consider the length of the stairs and slope equal.
1
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0answers
29 views

Physics of exercising and forces felt

Let's imagine an ideal scenario where you're lifting your own weight in its entirety. Let's say a woman weighing $100$ lbs. Suppose she's doing an idealized handstand and pushup from that position. So ...
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2answers
110 views

Physics of Weight-Lifting [duplicate]

I have a question regarding the concept of "work done" in Classical Mechanics, inspired by my time in real life situation of me the gym. "Work done" depends on the direction of the ...
0
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2answers
108 views

Does home cooking induction stove produces any harmful (to humans) electrical/magnetic fields?

An induction cooker, or stove that are based on the principle of electromagnetic induction, and is used much, for cooking food now a days. My stove had a thick iron circular plate on the top. Assuming ...
0
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1answer
38 views

Do Particle Accelerators Generate External Electrical or Magnetic Interference?

Among others, I am engaged in private pendulum research work during which there have been reports of disturbances of unknown pseudo-periodic human origin. It has been surmised that transmitted noise ...
4
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2answers
55 views

Why does oil make images not blurry?

This is about microscopes from biology. However, given that it's about lightrays, I figured that Physics is more suitable. In biology with a microscope, when we use the 100x microscope, we are told by ...
5
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2answers
276 views

Physics of the Planche

The planche is a gymnastics exercise where the athlete holds their body parallel to ground supported only by their hands. People sometimes train for this exercise using a progression of ``planche ...
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0answers
49 views

Why is BMI measured in units of $\text{kg}/\text{m}^2$? [closed]

Body mass index (BMI) is a convenient rule of thumb used to broadly categorize a person as underweight, normal weight, overweight, or obese. Where $m$ is body mass and $h$ is height, it is defined as: ...
34
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4answers
9k views

Stood in front of microwave with the door open [closed]

I was cooking something in the microwave and opened the door early to check on it and the microwave didn't stop. I didn't realize this for a few seconds and when I did I shut the microwave off but I'm ...
3
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1answer
122 views

How many neutrinos would it take to kill you?

Of course, there are many different kinds, so let's assume: they'rre all standard $v_e$. they all intersect your body in random places. they are going at say, 10% of c (about accelerator speed). ...
1
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1answer
60 views

Do we have any example of fundamental forces not working or having errors? [closed]

When we read about DNA, we see that the laws of chemistry and biochemistry and biology are rigid. But once in a while these laws fail to act (correct me if I'm wrong) and that is the source of what we ...
1
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1answer
69 views

How should one lift a heavy object?

The lower lumbar region of the spine is susceptible to abuse while resisting excessive bending caused by the moment about the hip of a force F from lifting a weight: Here is a (mirrored) diagram of ...
6
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1answer
217 views

How to model RNA-DNA and DNA-DNA binding as a “string matching" problem in statistical physics?

I am trying to model the binding of a guide-RNA molecule with a target-DNA strand as it occurs before the CRISPR-Cas9 protein cuts the DNA. Both the RNA ($S_1 = \Pi_i \sigma_1(i)$) and the DNA ($S_2 = ...
2
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1answer
73 views

Is a short dip in a cold water really equivalent to 20 minutes of running?

I came across some article comparing a short dip in a cold water (2 mins) to 20 minutes of running in terms of the amount of calories burned. Would you suggest a way of doing an experiment that would ...
0
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0answers
72 views

How do I calculate the shear forces trough the lumbar spine during a deadlift?

I am trying to analyze the forces involved in a conventional deadlift: People sometimes hurt their lower back when performing a deadlift. My hypothesis is that the lower part of the deadlift where ...
0
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0answers
35 views

What happen if part of your body get in contact with the Martian atmosphere?

There is a similar question, that talk about your full body, which the main point is clear; Full body, you die. You hold your breath, your lungs rupture and you die faster. For me its clear this point,...
1
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1answer
122 views

Cannibalism and energy conservation [closed]

This question in biology forum asks why cannibalism is not an evolutionarily stable situation. In this respect one has to distinguish occasional and exclusive cannibalism - in the latter case one ...
27
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2answers
9k views

Is it safe to keep uranium ore in my house?

I bought 5.6 gr of uranium ore. The measured gamma radiation is 1µSv/h, we didn't have the instruments to measure alpha/beta radiation. EDIT: The gamma radiation was measured at 1cm distance. I also ...
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0answers
63 views

Resources on understanding the Orchestrated objective reduction

I was trying to understand the mathematics behind the theory of Orchestrated objective reduction, and clearly, first I read the original paper of Penrose & Hameroff. Then I tried some other ...
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7answers
5k views

How can we discern so many different simultaneous sounds, when we can only hear one frequency at a time?

As I understand it, the eardrum works like any other kind of speaker in that it has a diaphragm which vibrates to encode incoming motion into something the inner ear translate to sound. It's just a ...
1
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1answer
77 views

What does this quantum mechanics diagram about adaptive mutations mean? [closed]

I'm a current high school student and I’m aspiring to become a biochemist. I’m at the moment writing an article about adaptive mutations but there is a lot of tricky quantum mechanics in it which I ...
0
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4answers
125 views

What is the explanation of these phenomena? [closed]

A person can jump high raising his 60 kg weight while he barely moves a rock of 60 kg. A person can run fast with his massive 60 kg weight while he barely moves the same rock of 60 kg. An average ...
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2answers
175 views

Why can't humans throw as fast as bullet and what law is involved? [duplicate]

If desert eagle 7g bullet can accelerate the velocity to 560m/s (In Average) And baseball 149g can only be accelerate to the velocity of 45m/s (In History)
4
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3answers
76 views

Why can human body sustain relatively high (e.g. up to 30 atm) external pressure?

I found out from the Internet that for average people it's fine to sustain up to 30 atm external pressure, for example when diving. However, given a typical human palm size of 80 cm$^2$, 1 atm means ...
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6answers
120 views

In the limit, does walking slowly downstairs cost me as much energy as walking upstairs?

I am not a physicist. If I allow myself to roll down a hill, then apart from receiving bruises, I will expend no energy. Having suffered ill-health recently, it seemed reasonable for me to restart my ...
1
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1answer
40 views

Do smaller organisms (eyes) see smaller objects in greater clarity?

Do smaller organisms (eyes) see smaller objects in greater clarity? With the human eye, as I get "closer" to something, I can see it in greater clarity, does this "relative largeness&...
21
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6answers
4k views

How can ultrasound hurt human ears if it is above audible range?

Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz. Then ultrasound is above 20 kHz Occupational exposure to ultrasound in excess of 120 dB may lead to hearing loss. Source How ...
34
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11answers
9k views

Why can't the human eye focus to make blurry photos/video clear?

The human eye focuses by flexing the lens, changing its focal length. When we switch from looking at a near object to a far object, our lens flexes, moving the focal length such that the near object ...
3
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1answer
96 views

What could be a good potential function for flocks of birds?

I am interested in modelling flocks of birds but I have difficulties finding a good candidate for my potential function $V(\vec{r})$. It would need to have the following characteristics: A short ...

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