Human Definition and 895 Threads

Something new every day. https://www.nature.com/articles/s41598-018-23062-6

The next questions will be in english and spanish, since my birth language is spanish I may be mistaken in a few english words. --------------------------------------------------------------------------------------------------------------------------------------------- Spanish Debo advertir que...

The reason I'm writing this is because I would like to share my thoughts about this interesting thing I was thinking about. So we all know how animals and all other living organisms share a common microbial ancestor that dates back billions of years. Well, I just find it fascinating how when...

Homework Statement Hello All, I might be at best HS level physics understanding but I’m quick study and need guidance. I am in a debate with someone who thinks a body can be crushed to the point of dust. I’d like to know if a comparison can be made, basic ratio: Human crushed by a building at...

During these days, I have asked my mother: What is better/worse for the human body: salt or sugar? Both of these substances are quite dangerous in high amounts, but which one is worse? Salt was used in food preservation, with its abilities (Which abilities? I have never understood this...) and...

I was pondering human evolution on different continents recently and some thoughts occurred to me: 1# the distance a region is from the equator determines the temperature of a climate all over the Earth 2# humans have probably been in regions of varying distances from the Equator long enough for...

https://en.wikipedia.org/wiki/Most_recent_common_ancestor I was reading about the human most recent common ancestor (MRCA) at the above link at Wikipedia. According to this article at Wikipedia, there have been common human ancestors to all humans alive today. This sounds far-fetched to me...

I have read things saying humans see 2d and also things saying its more like "two and a half d" but that humans don't actually see in three dimension. But when you explain the spatial dimension, you start with the first which can be explained by a line. So anything living in 1d would only be...

I only have a background in mathematics, and I lack knowledge on this matter. I want to get quantitive value about that problem. What would be the kind of wave or EM field that could heat human tissu of 1°C in (say a body part like the thigh), say in one hour, at a distance of 2m ? We could...

First let me tell you the context: There was this recently discovered tiny sealstone depicting warriors in battle measuring only 1.4 inches across. This piece contains incredible detail that modern human eye cannot discern without a mechanical aid. Read more at...

I am not a professional in this field so please bear with my ignorance. I try to be science literate where ever I can.My question is: Do genetics broadly and haplogroups more specifically rule out humans descending from more than one gene pool of common ancestors?To put it another way: Could it...

In my Thermodynamics course, we recently learned about the saturation pressure and saturation temperature of different substances -mainly water. As you know, the saturation temperature at which a substance begins to boil is specific to a fixed saturation pressure. Water only boils at 100...

Hello everyone, I know that the any object, human body included, when the vertical line from its center of mass to the floor falls outside the base of support, topples under the influence of gravity: the force of gravity produces a nonzero torque that rotates the body. Is the human body able to...

What types of light are able to pass through the human body without causing damage to tissue or individual cells? Are there any truly safe alternatives to x-rays that could allow doctors to see internal body parts but not cause damage from extended exposure?

What is it in the human brain that causes a person to believe completely something that is fictional such as astral projection or that theyve talked to God so to speak. How can said person believe fully that they have experienced such a thing whilst knowing it is impossible. Basically I am...

I've been wondering about modeling human traits that seem to have a universal aspect of nature. Though this is worthy of another topic, on a more fundamental level or serving as a good example, can 'masculinity' have a more objective measure of measuring it and formalizing it. In other words, is...

Hello, It is well known that the atmospheric air pressure is significantly strong but our body does not get crushed by it because and equal pressure pushes from the inside our body. That said, does it mean that air can exist and be diffused inside solid organs like the lungs, our heart, etc...

Homework Statement Some cell walls in the human body have a layer of negative charge on the inside surface. Suppose that the surface charge densities are ##±0.50 \times 10^{-3} C/m^2## , the cell wall is ##5.0 \times 10^{-9} m## thick, and the cell wall material has a dielectric constant of...

Hello, I read in my physiology book that when the ciliary muscle relaxes, the power of the eye lens decreases, hence we get the ability to see far objects. I am new to physiology, and when I googled "the power of the eye lens" I didn't find articles explain the sentence above simply. So I...

I have thinking about this issue quite a lot recently; Imagine a class of students where students don't ask any questions to teacher; All of the communication is only from teacher to students. ( I myself have attended such classes when I was a student.) In such class why teacher can not be...

Hello, I've been watching too much anime. I know that isn't the best way to ask a question scientific in nature, but visualizing bizarre situations is one of the best ways to come up with interesting questions. Anyways, in order to break a rock by compressing it with your hands, you would need...

Homework Statement Please could someone help me with how raw data should be dealt with when using a human operated stop watch. I have attached the information we were given and it makes little sense to me. Homework Equations See attachement The Attempt at a Solution We are constantly reminded...

I've often wondered at the "resolution" of the human visual system but it's not at all clear from what I've read whether this question even makes sense. As a sort of general position, many of the articles I've read suggest that the human eye, over the full field of vision, delivers around...

There are two optically transparent tissues in the human body: the cornea and the lens. But how they achieve this transparency is different, and both in turn appear to achieve this differently than in other optically clear materials like glass. The transmission of light through glass or other...

Hi, all. I'm nearly 14, and self-teaching physics and mathematics. One quote of Newton's really inspires me. It is the 'Shoulders of giants' quote, and even though it was just Newton taking a stab at Robert Hooke's short stature, it has meaning to me, and probably you guys, too. I want people to...

What does this mean, and is it true?

In the thread https://www.physicsforums.com/threads/first-human-embryos-edited-in-u-s.921238/ the film Gattaca was discussed as an example of a very bad society brought about by the use of human genetic manipulation. In my opinion the Gattaca society is a very poor example of this in that is is...

I read that cells in human body are continuously oxidized. Can you explain in layman's term what this means? Is it possible to explain cell oxidation withot reference to "electron loss." Because I cannot imagine visually how a cell can lose an electron or what that means.

Researchers have demonstrated they can efficiently improve the DNA of human embryos. https://www.technologyreview.com/s/608350/first-human-embryos-edited-in-us/

So a few months or years ago I learned that most of the energy from swinging comes from raising the center of mass at the lowest point of a swing. I also recently found a method of swinging that maximizes this energy gain. You squat on the swing, and stand up every time it gets to the lowest...

I need a better understanding and explanation of how a percussion wave form can move through biological soft tissue. I know that human soft tissue functions microscopically in a fluid environment however I also understand that there are also obstructive forces in the way of a wave moving in a...

I have been thinking, looking for an answer. It is known to me that drinking pure H2O is bad for the body, reason is it saps all of the minerals from the body since it does not contain any. I have been thinking, if I take salt water from a certain sea, put it in a container and boil the water...

First of all, it's not intended to be a philosophical question, but rather a physical one. So, what can we say about time? Maybe, it's a human way of measuring how things evolve in space? Suppose there are a room with objects within it, where nothing ever happens. There's no need to talk about...

What's the average aspect ratio of human vision as we perceive it?

It will be interesting to see what comes of this. https://www.yahoo.com/news/homo-naledi-mystery-human-species-091635429.html

Hey all, *this is my first post on this forum* I've read a lot about the different ways of artificial gravity on this forum, and we've discussed everything from realistic ideas that can be accomplished with today's tech, all the way to fictitious situations in sci fi books. BASICALLY, I would...

http://science.sciencemag.org/lookup/doi/10.1126/science.aam9695']science.sciencemag.org/lookup/doi/10.1126/science.aam9695[/PLAIN] Researchers have found a way to extract DNA from cave floor sediment strata. Mixed in with a lot of other mammalian DNA is DNA from Neandertal and Denisovan...

Beautiful video. Useful perhaps to educate people who are ashamed of our primate cousins? Richard Dawkins says he is proud to be an African ape.

Greetings to all, I realize that there is another "dead thread" about this subject (with a lot of interesting comments) but I think I can add a "new dimension" to the conversation.:smile: I have also put this question out on a few other Science Forums... The human eye is much like the lens of a...

Mentor note: Split the thread in two parts, the other part is here: When (and Why) Does a Human Baby's Vision "Flip". This thread discusses the inversion of human vision, "up/down", "left/right" and 180 degree rotations. Greetings to all, I realize that there is another "dead thread" about this...

I've been stuck on this physics problem for several years now. I would be very grateful if someone could explain how to solve this problem. The farthest a human could travel from Earth in one lifetime theoretically is limited only by the acceleration a human can withstand, and the length of...

I'm not sure if this is the right area of the forum (it may be more Earth physics) or even the right site for this (it might be more of a geology question), but I'm wondering if someone more knowledgeable in physics could explain the physics of human caused earthquakes to me. Recently the United...

This week on, Feb 14, the US National Academy of Sciences and National Academy of Medicine released a report giving recommendations on how...

I am looking for resources on the physical properties of the various components that make up the human body. As an example of what I am looking for; If we look at the finger, we know it has bones, skins, nails, blood etc. What are the various physical properties of these different parts...

I read posts from a few years ago regarding measuring frequencies in the human body. I am wondering if there are any new developments. What devices can measure frequency? Thanks!

If Venus had an atmosphere similar to that of Mars, would Venus then be a more attractive target than Mars for human colonization?

Some claim not possible naturally, ie beat 2 hours. While not possible under race conditions Nike is trying to see if it is humanly possible; http://running.competitor.com/2016/12/news/nike-launches-program-break-2-hour-marathon-barrier-2017_160032

Hi all, Would anyone be able to let me know what the average frequency is for the human body? Also, what is the average frequency of a home? What would be considered abnormal? According to the Ofcom UK Frequency Allocation Table it notes different frequency uses e.g. a frequency of 1,600...

I have seen books and videos that claim to teach you how to become a human calculator. does this stuff really work? if it does can you recommend a good book or video ?

Dear PF Forum, It's been a while that I've been wondering. Where did people from particular island in Indonesia come from? Here is the map As I understand it, homo sapiens came out of Africa 70 thousands years ago, and they went to Australia. Is that why that our brothers (and sisters) from...