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.
Questions tagged [biology]
535 questions
119
votes
18 answers
How does mass leave the body when you lose weight?
When your body burns calories and you lose weight, obviously mass is leaving your body. In what form does it leave? In other words, what is the physical process by which the body loses weight when it burns its fuel?
Somebody said it leaves the…
exokernel
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93
votes
9 answers
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 $7\,\text{kJ}$ of potential energy. Where does it go? Is it all getting dispersed into heat and sound? Is that heat being generated at the point of impact between my feet and…
A. Kriegman
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79
votes
5 answers
Why can we distinguish different pitches in a chord but not different hues of light?
In music, when two or more pitches are played together at the same time, they form a chord. If each pitch has a corresponding wave frequency (a pure, or fundamental, tone), the pitches played together make a superposition waveform, which is obtained…
chharvey
- 878
70
votes
6 answers
How does light combine to make new colours?
In computer science, we reference colours using the RGB system and TVs have pixels which consist of groups of red, green and blue lines which turn on and off to create colours.
But how does this work? Why would certain amounts of red, blue and green…
Isky Mathews
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55
votes
3 answers
Why don't electric fish shock themselves?
Fish like electric eels and torpedoes have specially designed nerve cells that allow them to discharge hundreds of volts of electricity.
Now, while pure water is usually nonconductive, the dissolved salts and other stuff in both sea and fresh water…
user172
52
votes
3 answers
Why aren't 100% UV blocked sunglasses safe to view an eclipse with?
I am not planning on staring into the sun during an eclipse or any other time.
I have been reading about how no variety of regular sunglasses are safe enough to view the eclipse with. I'm not talking about being able to see things clearly, but just…
Jeff
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51
votes
6 answers
Because things smell, is everything evaporating?
Everything, in theory, can have a smell, but that is not the whole point of this question.
My main query is, since things do smell, does that mean that everything is slowly evaporating (or, sublimating, I suppose)?
For example, if we perceive metal…
deed02392
- 637
50
votes
4 answers
Could I survive at (or near) absolute zero with a very, very, very thick sweater?
Imagine I'm in an infinitely large vacuum and have a special apparatus built into my body that allows me to breath, eat, pee/poo, etc. and never age. The vacuum is similar to deep space and has no heat source or visible light and is therefore quite…
Behacad
- 607
46
votes
13 answers
Why aren't we bumping into objects outside of the visible range?
Apologies if this is too simple of a question for this site. My physics education stopped at the undergrad level. My 12 year old nephew asked me a question and I couldn't give him an answer. He asked, upon learning the human eye could only see…
gary
- 569
46
votes
4 answers
At which slope angle is a runner faster than a bicyclist?
On level terrain a bicyclist is faster than a runner.
On a steep slope a runner is faster than a bicyclist.
(That's why you see bicyclists pushing their bikes uphill.)
Can we calculate the angle where it becomes more advantageous to discard the…
summerrain
- 576
45
votes
12 answers
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, we have no idea how physics determine every…
user236241
45
votes
6 answers
Does pure yellow exist in variations we can't discern?
If you add red light (~440 THz) and green light (~560 THz), you get what we perceive as yellow light (~520 THz). But I assume what you really get is a mixed waveform that we perceive as yellow? Suppose the red is a perfect sine wave, and so is the…
commonpike
- 579
41
votes
3 answers
Can ants walk on liquid mercury?
I'm not a physicist, but I was wondering:
Can ants walk on dense liquid like mercury and why?
Apolo
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34
votes
4 answers
Stood in front of microwave with the door open
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 concerned what I could have been exposed to for…
Mr.Smithyyy
- 467
34
votes
11 answers
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 is out of focus and the far object is in focus. …
Ryan_L
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