What is Head: Definition and 411 Discussions

A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste, respectively. Some very simple animals may not have a head, but many bilaterally symmetric forms do, regardless of size.
Heads develop in animals by an evolutionary trend known as cephalization. In bilaterally symmetrical animals, nervous tissues concentrate at the anterior region, forming structures responsible for information processing. Through biological evolution, sense organs and feeding structures also concentrate into the anterior region; these collectively form the head.

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  1. C

    If two trains traveling at 0.5c collide head on

    What would happen? These two trains are on the same tracks moving at constant velocities towards each other (0.5c --> and <--0.5c I guess) so what would happen? Since all motion is relative and no mass can travel at the speed of light something else must happen instead of a light speed head-on...
  2. S

    Calculate Work, Isentropic Head & Efficiency of a Centrifugal Gas Compressor

    Hi everyone! I have a question and I would be so thankful if you could help me! For a Centrifugal Gas Compressor, if I have the flow rate, the input and output temperatures and pressures in specified rpm, then could I calculate its needed work, isentropic head and efficiency? how? Thanks! Sara
  3. DevilsAvocado

    News What’s wrong in the head of Corporal Morlock and the others in the 'Kill Team'?

    This makes me XXL *** Warning! Horrific Photos! *** http://www.spiegel.de/international/world/0,1518,752310,00.html [PLAIN]http://www.bakersfieldalternative.com/wp-content/uploads/2010/09/StrykerSoldiersKillSquad.jpg Andrew Holmes, Michael Wagnon, Jeremy Morlock and Adam Winfield
  4. F

    Medical Can psych meds cause a persons head and shoulders to grow

    Ever since I have been taking psych meds, since I was 18 I think; my head and shoulders have grown really big. When I graduated from high school I looked completely normal, but now my head and shoulders are gigantic. Plus my back sticks out now. It is like I am a tall hunch back.
  5. F

    Medical What causes some people to want to roll their head

    Ever since I was a very young child I have rolled my head while laying in bed. I don't roll my head the entire time that I am awake, but I do roll my head a lot.
  6. F

    Is holding a box over my head work, or not?

    I know that work=force*distance. So here's a scenario for you. Suppose I hold a heavy box over my head. I keep holding it until I get very tired and cannot keep it up. Naturally the box then falls to the ground at my feet. At that moment, the Earth's gravitational field performs work on...
  7. D

    How does perimeter weighting affect the moment of inertia of a golf club head?

    "In the last 25 years, designers have developed clubs that have approximately the same weight as the older clubs but have it distributed around the perimeter of the club, so that the head is far more resistant to off-center twisting and therefore far more forgiving of golf swings that are off...
  8. R

    Cylinder head and Cylinder block

    can some one please refer me operating conditions for cylinder head and block of diesel and gasoline engines. I have searched through google but couldn't find any definite info on that. I need numerical values of temperature, pressure that head and block must withstand.
  9. R

    Slurry pipeline and pump head

    Hey folks, I'm trying to do a bit of back-of-the-envelope stuff for a hypothetical slurry pipeline, but it's been a while since I've done any fluid mech./dyn., and I have no confidence in my numbers -- please jump in wherever you catch an error. First of all, I'm making the assumption that...
  10. S

    Is tilting your head back linear acceleraton? Super quick question

    Hello, I need to know what linear acceleration and angular acceleration of head is. This is not for physics, this is what I'm thinking, if I'm wrong please correct me and tell my why not Shaking head-angular acceleration Tilting head back- angular acceleration (Just in case this becomes...
  11. B

    Keeping a consistent hydraulic head in a drainage pipe

    Hey everyone, I've got a problem here and I'm looking for a simple solution. Basically, I need to keep a consistent hydraulic head between two points of a vertical drainage pipe. I have a sump pump and two electronic float valves (that I purchased separately). What I want to do is wire the...
  12. J

    VB app to calculate velocity of a golf club head

    Hi guys, i have read and read and read all this stuff about x=vt(cosA), y = vt(sinA)-1/2gt^2 now i am not a pyhsics guy and never claimed to be, i am a programmer. This is what i am trying to accomplish. I am trying to write a small VB app to calculate velocity of a golf club head. I and...
  13. D

    Why does hair on a human head grow indefinitely?

    Given that we humans are descended from the great ape, as well as are gorillas and chimpanzees and bonobos, why do we have hair that grows indefinitely, while they do not? I've read something about a sexual selection aspect to evolution, surmising that hair is a means to finding a mate, like...
  14. A

    What is the true impact speed when two cars collide head-on at 50mph?

    Its probably been done previously but a search didn't return any results for me. But anyway, Vehicle 'a' (Va) travels head-on into Vechicle 'b' (Vb). Both are traveling at 50mph. Both vehicles are identical in weight, tyre grip, transmission, general design, road surface etc. Is the...
  15. E

    Has anyone else ever gotten in over their head?

    So I went a bit overboard this semester and took 4 math courses and a fifth math-based course, and while 80% of the courses went well, one didn't. I took an upper level statistics course because I liked the professor, and it's one of the core courses at my school if you wish to do an honors...
  16. F

    Civil Engineer needs help getting head round a graph

    Hi, new to the forum, although i have read some posts before. I am in the process of completing a structural mechanics report based upon buckling of a slender column. In the brief they asked us to plot a graph of Critical Buckling Load derived from Euler's Buckling Theory and actual (all...
  17. E

    What is the Leachate Collection Rate for a Landfill with Clay Liner Systems?

    Homework Statement...
  18. E

    Pump head and flow rate relation

    i need some help becoase i become confused according to pump characteristic curve if the flow rate increased the head will decreased the question is how i can increase the flow rate and what is the relation of RPM with head and flow rate
  19. S

    Extruder Head: Cable manufacturing

    Hi, I'm having trouble producing 22 AWG polypropylene cable. I keep on getting "missing insulation" and "reduced insulation". The Extruder Head I'm using is quite old and I'm not sure that it is "centered". But a mechanical engineer told me not to worry, it doesn't mater if the Head is...
  20. S

    Extruder Head: Cable manufacturing

    Hi, I'm having trouble producing 22 AWG polypropylene cable. I keep on getting "missing insulation" and "reduced insulation". The Extruder Head I'm using is quite old and I'm not sure that it is "centered". But a mechanical engineer told me not to worry, it doesn't mater if the Head is...
  21. Spinnor

    Slippery finger pushing on a large drum head.

    Say I push down on a very large drum head that lies in the z = 0 plane at equilibrium. Suppose there is no friction between my finger and the drum head. Suppose my finger tip pushes the drum head down some distance d. Suppose I accelerate my finger tip to some constant velocity v in the x...
  22. mugaliens

    Cycads, athletic head injuries, and ALS

    I recently ran across a couple of comments to http://news.yahoo.com/s/ap/20100817/ap_on_sp_fo_ne/fbn_head_injuries_als" As an athlete who's had several head injuries over the years, but one who has never eaten cycads (that I know of), what might I expect? What should I do? Avoid brown...
  23. G

    Binomial series vs Binomial theorem, scratching my head for three days on this

    In my book, it says that the Binomial Series is \sum_{n=0}^{\infty }\binom{n}{r} x^n Where \binom{n}{r} = \frac{n(n-1)...(n-r+1)}{n!} for r\geq1 and \binom{n}{0} = 1 Now here is where it got to be, I know that the \binom{n}{r} = \frac{n(n-1)...(n-r+1)}{n!} were derived through the...
  24. O

    How do you visualize the spin of electron in your head?

    How do you visualize the spin of electron in your head? I can’t imagine such a vector which has the same projection in any direction and at any time. Is it an understandable object in three dimension?
  25. M

    Extraction of iron on a match head

    Hi Please look at this link. It is only very brief. It describes how to extract iron from iron oxide on a match head. My questions are: where does the carbon come from in this equation Iron(III) oxide + carbon → iron + carbon dioxide 2Fe2O3(s) + 3C(s) → 4Fe(s) + 3CO2(g) Is it...
  26. Evo

    Medical Exploding Head Syndrome: Causes & Effects

    I've noticed a number of threads asking about sleep paralysis, and especially loud noises when falling asleep. I found this article and thought others might be interested. http://www.livescience.com/health/sleep-disorders-top10-100208-1.html The "loud noises" is a disorder called...
  27. M

    This problem has eaten up my head -

    Homework Statement A circus acrobat of mass M leaps straight up with an initial velocity of vo from a trampoline. As he rises, he takes a trained monkey of mass m off a perch of height h above the trampoline. What is the maximum height attained by the pair in terms of M, m, Vo, h, and g...
  28. N

    I have a frequency response diagram(frequency vs head) of discrete

    I have a frequency response diagram(frequency vs head) of discrete values. I have to perform Fourier analysis on these discrete values. The resultant frequency and head should be in FREQUENCY DOMAIN. how I can do this... by using FFT or any other ... using Nyquist frequency... please tell me...
  29. K

    Velocity of Head from Car Accident

    My friend was in a head-on collision this week. They were traveling approximately 35 mph. A car collided with them head-on traveling at approximately 30 mph. The airbag deployed, and the impact caused a tremendous contusion on my friend's forehead, but no skull fractures. It's been years since...
  30. N

    Bottom of bolt head compressing against the material it is holding

    Hi guys, If you look at the picture I have included, where a bolt is forced in compression against the plate it is holding, to which example from Roark's would this condition be? (i.e. annular plate with a uniform annular line load, outer edge free; inner edge guided... etc?) I am trying...
  31. L

    Why Do Tornadoes Form and Head Towards Earth?

    Why does a tornado vortex go down to Earth instead of up to the atmosphere? Sounds stupid I know, but answer the question if you can.
  32. R

    Simple Problem that I can't get my head around

    Okay, so I've been wondering about the Galileo experiment for some reason and I can't get my head around how it would work under different circumstances. 1. Is Galileo's experiment only valid in vacuum or is it valid for all kinds of fluids? Also, must the two objects be of the same...
  33. A

    What are Some Good Online References for Head Loss Coefficients in Ductwork?

    I am working on a project at my summer internship rerouting some duct work and want to do some calculations to see how much changing some of the 90 degree angles in the duct will improve flow. I don't have my Fluids text with me and was wondering if anyone knew of any good references online to...
  34. O

    Medical Concerning thoughts in my head.

    Hi, I have this thing where if I see someone this really negative thought about them will pop into my head about them, independent of my will, and it's growing in consistency. It'd be something awful like "you're so ugly" or "wow you're fat". Really disgusting stuff. It's turned into like a...
  35. J

    What do you picture in your head when you think about spacetime?

    Hi, I'm trying to learn stuff for my relativity module, and it goes on about spacetime and the 4-dimensional continuum and four-vectors and all that business. I am having trouble imagining whatever it is I am supposed to picture when people talk about this. Take this thing, i believe its...
  36. F

    System head curve for tree piping system

    as we know to draw the system curve of a piping system we have to change the value of Q total and get a head for each value we put in the following equation : H=Hstatic +Kq^2 where K is the sum of major and minor losses. what if we have a piping system that have many branches "tree -system"...
  37. P

    Cant get my head around gaussians, so easy aswell?

    Hi there was wondering if some one could help me? I think i understand what a gaussian is, its a normal distirbution where the distribution of data symmetrically tails off from the mean in both directions. I have been looking at FTIR error analysis and have constantly read that error is...
  38. L

    Not sure where to head, and need to determine soon.

    So my junior year is winding down, and now is the time for me to start applying to grad schools. The problem is that I'm not sure what subject I want to enter into, much less which schools to apply for. Currently, I am completing a B.S. in computer science and a B.S. in psychology with a...
  39. F

    Sizing Open Pipe System for Equal Head Losses

    If we have an open pipe system that will deliver in total 200 gpm divided in 2 pipes the first pipe is 50 gpm and the second is 150 gpm , the 2 pipes have the same length , if we want to size the pipes where both pipes will have the same diameter , if we do that through william hazen equation...
  40. Z

    Calculating Head Loss in Pumping System for Swimming Pool Design

    Homework Statement I have to design a pumping system. Its for a swimming pool. The pool has various fittings (valves, etc) and pipe lengths. My problem is I cannot find an appropriate K value for the filter and sieve. On the suction side of the pump is various valves and a sieve to...
  41. G

    A box falls one metre and hits a womans head

    I need some scientific assistance. A woman at work had the misfortune of a box falling and hitting her head. Fortunately she was fine, the box was not heavy and she had no injuries. Two years later i have a solicitors letter demanding money for fictitious injuries. Is it possible to get an...
  42. J

    Probability a coin lands on head

    For A coin that comes up heads independently with probability p on each flip what is the variance in the number of flips until the kth head appears ?
  43. T

    Match head rubbed over a distance

    Hi, I'm trying to work this problem out and unfortunately my book doesn't have an explanation. Homework Statement A match head is rubbed a distance d over a rough surface in order to increase the temperature to its flash point. If the patch head material has a mass m and a specific heat...
  44. S

    Acceleration problem-how to incorporate head starts?

    Homework Statement A pedestrian is running at v=6m/s (continuously) to catch a bus that is leaving from 16m in front of him. The bus pulls away and accelerates (from rest) at 1m/s/s. How far does the pedestrian have to run to catch the bus (if at all)? V pedestrian=6m/2 acceleration...
  45. M

    Constant Head Tank: Calculating Net Head, Flow Rate & Pressure

    Hi all, I got the system (attached below) and I am trying to work out the following (at point x-outflow): -net head of the system (I guess this isn't really at point x) -flow rate -pressure I know the flowrate and pressure at point Y, I also know how high the water in the tank is at...
  46. P

    Are You a Dead Head Who Appreciates Math?

    Anyone here a dead head? There's really no point to this post, so i won't be surprised if it gets no replies. That said, I was listening to The Weather Report Suite earlier today, and I was suddenly overcome with (albeit vague) application of Fourier analysis to the interpretation of this song...
  47. I

    Hydroelectric turbine.. net head question.

    Sorry, not so much of a problem, more. . I need to understand. Homework Statement Finding the net head. This website (http://www.oregon.gov/ENERGY/RENEW/Hydro/Hydro_index.shtml ), says that the gross or "static" head is the vertical distance between the top of penstock and the point...
  48. M

    When 2 particle beams meet head on

    When 2 particle beams meet head on, more energy is avaliable than when the particle beam is directed at a fixed target. Why is this? My textbook gives an explanation which I don't understand, involving rest mass energy. Any alternate explanation or explaining the one given will be great...
  49. R

    Can a Beginner Succeed in Intermediate Java Programming?

    Well I have literally zero programming experience and I am a freshman so I decided to take a Java class. Problem is that I heard the intro class is an absolute joke and I don't really want to waste time on it. The next prerequisite for the intermediate class is only "the equivalent to a High...
  50. K

    Have a few vector questions I cant seem to get my head around.

    1. Homework Statement Ok, so here are the questions, I literally have no idea how to begin on them. 1.Show that the vector 2i+3j+3k is normal to the plane containing the points (1,1,-2), (4,2,-5) and (1,-1,0). Hence find the equation of the plane in the form (r-a).n(hat) what is the...
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