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. R

    My new discovery turns science on its head

    I'd like to publish this in a peer-reviewed journal, but they'd probably reject it. I think General Discussion is an equally valid medium. "Synthesis of Instant Coffee using Non Heated Water" rachmaninoff PF Institute For Coffee Science* *not affiliated with the...
  2. 3

    Fastest way you have found to multiply two numbers in your head?

    This is a mental arithmatic question really, but what is the fastest way you have found to multiply two numbers in your head? How many steps does it take you and what shortcuts do you use? I apologise if this is the wrong forum. Examples: 33x24 123x321 9999x6666 etc..
  3. P

    Understand Inlet Kinetic Head Loss for Venturi, Orifice & Rotameter

    I am working on a lab regarding the flow of water through various meters, i.e. Venturi, Orifice and Rotameter. One of the things we are calculating is the Inlet Kinetic Head loss of these meters. My problem is this, I have not taken any fluids courses yet, and have no concept of what this is...
  4. Mk

    Head Sweating: Causes & Solutions

    My head perspires more! Is this an illusion caused by my hair holding the water longer, or is it that my head really sweats more? Or both? Why might this be? Because the brain more importantly needs to stay cool?
  5. S

    Motor Shaft Attachment for Small Electric Motor - Suggestions?

    on a smaller electric motor the motor output shaft is cylindrical with a hex head insert i am just directly attaching it to a small tire is there a certain type of drive shaft that anyone could recommend i thought about using an old allen wrench but had nothing to hold the drive shaft into...
  6. M

    Determining head versus flow rate curve.

    I'm doing a lab on Laminar Flow Elements - Fan Performance Test. So far I have had to find power coefficients (CP), discharge coefficient (CQ) and head coefficients (CH). I've plotted CH vs. CQ, CP vs. CQ and Efficiency vs. CQ. My last requirement is that I "Use the curve fits to...
  7. Ivan Seeking

    News MEET THE PRESS: Celebrating 58 Years on NBC!

    http://www.msnbc.msn.com/id/9898884/ It just blew me away to think that this goes all the way back to FDR's people. As with http://www.pbs.org/newshour/" on PBS and a few other sources, the chance to watch extended interviews with the people making the news is invaluable. Russert carries on...
  8. wolram

    Decapitated head can still be alive up to 10 seconds

    In this article it states that, a decapitated head can still be alive up to 10 seconds from removal from the body, and in some cases the practice was stoped on humane reasons, and that animal heads have been transplanted, the article is from wiki so i guess it is well researched, in the light of...
  9. H

    Power source that turns physics on its head

    "Power source that turns physics on its head" Welcome. I am curious about what you knowledgeable folks here at PF think, regarding this current event. I searched for any threads which already regard the topic, but found only two with very limited discussion. Fuel's paradise? Power source that...
  10. J

    Medical Earworms & Other Thoughts Stuck in the Head

    According to wikipedia, earworm, a literal translation of the German Ohrwurm, is a term for a song stuck in one's head, particularly an annoying one. Use of the English translation was introduced by James Kellaris, an associate professor of marketing at the University of Cincinnati. His studies...
  11. M

    Having troubles wrapping my head around this design, also confused on directions

    One of my questions say: Designa combinational circuit that accepts a 3 bit number and generates a 6 bit binary number output equal to the sqaure of the input number. Now when it says it wants a 3 bit number as the input does it mean like ABC 000 001 010 011 100 101 110 111 then...
  12. A

    Understanding Solid Fuel Rockets: Tail or Head, What's Best?

    Can somone explain me how solid fuel rockets works? Where should I start the reaction, at the tail or at the head? What fuel is the best?
  13. honestrosewater

    Get my friend to use her head?

    This is my friend's problem, not mine. I don't know who the guy is, and I'm not telling or answering guesses, because I wouldn't want to embarrass him if I knew him, which I don't. Okay, so... My friend is kind of developing a crush on this guy, and I'm trying to convince her to just nip it...
  14. I

    What is the Space Shuttle's Velocity at Various Altitudes?

    Math teacher in over his head :) Not so much "over my head" as I don't have as much time as I'd like to research the answers. My 7th grade honors class is doing a project on "How fast is the Space Shuttle in terms of Mach?" (My title, not theirs :) ). They didn't have too much trouble...
  15. J

    Remote Control + Head = further distance?

    Remote Control + Head = further distance? huh? has anyone else noticed this? I'm sure you have? has anyone got an explanation for it? like... when you put your car remote, you get about 10ft more range from it... or a garage door remote, about another 30ft when you put it against your...
  16. U

    How'd he know there was sh.it on his head?

    there are 3 men. they can see each other but not themselves. there is a piece of birdsh.it on each of their heads. they start laughing at each other. the wisest out of the 3 guys stops laughing, he stopped laughing because he figured he had sh.it on his head. how'd he figure it out?
  17. H

    So please advice me."Help! Unbearable Head Pain - What Could It Be?

    Guys This is very very serious. Yesterday the time was 1 o' clock when i logged off and went to sleep.At that time i could sense a little pain building in my head but as i lied down,I was thinking deeply on something,simultaneously the pain was increasing and i believed that it was weird and...
  18. Monique

    Things I can't get my head around

    I used to have a summer job in agriculture, peeling flower bulbs and also planting tiny little plant shoots, but there are a few things I don't understand.. 1) how do they remove the pit out of olives or cherries and keep the fruit intact, whenever I try to do that they are left mangled in...
  19. T

    Building Sun Resistance for a Bald Head

    okay I know my the top of my head hasnt been exposed to much sun so it will burn easily since I shaved it BUT isn't it good that it gets SOME exposure to sun so that it will build resistance to it? Thanks
  20. T

    The Risks of Shaving Your Head: Non-Appearance Issues

    I shaved my head to save time/money/energy but now I think I'll let my hair grow back because of the increased risk of skin cancer and sunburns and stuff. Are there any other problems (Like that) that shaving my head could cause? (I mean that aren't appearence-related)
  21. L

    Does a fly move relevant to your head?

    Just a simple question: Does a fly that buzz around your head while you travel on an open boat (with some sort of wind screen in front) move relevant to you, and therefore travel at higher speed with no more effort than it would if your boat stood still?
  22. recon

    Momentum head on collision problem

    A B --> <-- 24kgm/s 10kgm/s Two trucks A and B are about to collide head on; their values of linear momentum are as shown in the figure above. After the collision the two trucks separate and move away from each other, at which time truck A has a linear momentum...
  23. T

    Calculating Flow Rates in Pipe Networks: Head Loss Equations

    Hi. I'm trying to determine the flow rates of water in a pipe network. At a junction in a pipe, for example a simple y junction where the water heads out of a tap down a short length of tube before splitting into two lengths of tube of the same diameter, would the head loss equation for one of...
  24. O

    Strange Occurrences: The Number 20 or 27 in My Head

    For a while now, id say a matter of months that i can remember, i will say the number 20 or 27 in my head. I never mean to or plan to, but i still do from time to time. It hasnt happened lately, but its very strange. I will be walking from class to my apartment and talking to myself in my head...
  25. DaveC426913

    Why Do Birds Bob Their Heads When Walking?

    Belongs in a 'nature' forum, but this is as close as it gets. Why do some birds (pigeons, starlings) bob their heads (front and back) when they walk? I have two hypotheses: 1] They have lower retinal retentiveness, and must hold an image on their eye longer to resolve it. They move their...
  26. M

    Voices (and not the kind in your head)

    So my physics class is studying sounds and light waves right now. We were discussing how different things affect the sound waves. My question relating to biology is this: my mother and sister and I sound very much alike...except that they tell me my voice sounds as though it is a lower pitch...
  27. H

    Extracting Square Roots in your head

    What are some good quick ways to Extract Square Roots in your head. I'm looking for a method that is very prescice and easy thanks, hopefully somebody helps me out
  28. K

    What is the Velocity of Gliders A and B in an Inelastic Collision?

    Given: Two gliders on an air track collide. Glider A has a mass of 0.269 kg and is moving in the +x direction with a speed of 1.07 m/s. Glider B has a mass of 0.330 kg and is moving in the -x direction with a speed of 0.675 m/s. a) What is the velocity of A and B if the collision is...
  29. J

    Head-on Collision: Solving for Ball A & B Velocities

    Can anyone help me with this problem? Two billiard balls of equal mass undergo a perfectly elastic head-on collision. If one ball (ball A) is initially moving at 1.9 m/s in the +x direction, and the other (ball B) is initially moving at 3.9 m/s in the -x direction, what will be the...
  30. JasonJo

    Head scratching integral calculus hw

    hey guys, i need help on my integral calculus hw 2) int(x*3*e^(x^7)) dx this one is just giving me insane problems
  31. S

    Head on Collision with a car physics

    Lost in this review problem: Most of us know intuitively that in a head-on collision between a large dump truck and a subcompact car, you are better off being in the truck than in the car. Why is this? Many people imagine that the collision force exerted on the car is much greater than that...
  32. Clausius2

    Is This New Piston Head Concept Effective?

    I want to share and discuss with every forum posters here a new concept on piston heads, which by the way is not as brainy as you may think. The new concept is concerned with spark ignition engines. Everybody know that combustion process have two main stages in this kind of engines...
  33. S

    Head On Collision Of A Two Mass One Spring System

    :confused: [SIZE=7] PLEASE HELP WITH FOLLOWING PROBLEMS ATTACHED WITH THIS ? :cry:
  34. S

    What does a head on collision imply?

    what does a head on collision imply? does it mean that the photon will be bounced back 180 degrees ?? If this is the case we now know where the position of the electron in the atom, but the momentum is uncertain because it had some 'inital' momentum right??
  35. A

    Denethor gets thumped in the head (again)

    Not only Gandalf loses his patience with this obnoxious fellow; Dr Zhivago became equally irate (or at least, Peter O'Toole did) http://www.hindustantimes.com/news/7242_1088085,00180007.htm Any sympathy for John Noble here?
  36. T

    Head-on Collision: 4.5 kg & 11 kg Objects

    A 4.5 kg object with a speed of 4.0 m/s collides head-on with a 11 kg object moving toward it with a speed of 3.0 m/s. The 11 kg object stops dead after the collision. (a) What is the final speed of the 4.5 kg object? (b) Is the collision elastic? so i tried initial momentum = final...
  37. P

    Basic Physics - Spinning Head (mine)

    Hello again all. This is my 6th posting requesting some assistance for some new physics problem. It is getting a bit easier to understand but I would like some review and comments on the following problems. My answers are marked with an astericks. You do not have to necessarily provide me...
  38. F

    Can tungsten nanorods harness air molecules to create propulsion?

    Reduceing atmosphric pressure Six electrical contacts as small and as close as we can make them on a surface. Call them ABCDEF. Apply current to C&D electrons are separated from air molecules in contact with C&D. Apply a positive charge to A the electrons will be drawn to A across B. Apply a...
  39. E

    What does a Deaf person sound like in their own head?

    So what does a person, born deaf, sound like in his/her own head? I know what I sound like in my head. I wonder what these people sound like. Do they think in visual's? And if that's the case what does a Blind and Deaf person sound like or see like in his/her head? :rofl:
  40. D

    The webpage title could be: Calculating the Force of Air on Your Head

    Ok I have the following question: If the top of your head has a surface area of 113 cm2, what is the weight of the air above your head? I'm not sure what I am doing wrong. I used the P = F/A. Solved for F to get F= P/A. I'm assuming the question is asking me for the force of the air on my...
  41. Tsu

    News Is the US Really Seeking Domination in the Middle East?

    "Kerry Hits Nail on Head" Gosh! I'm just finding interesting stuff all OVER the place! :biggrin: Kerry Hits Nail on Head By Marjorie Cohn t r u t h o u t | Perspective Monday 04 October 2004 http://www.truthout.org/docs_04/100404A.shtml
  42. P

    How much force did the rock exert on my head?

    Struck in head by rock! This past Sunday I was rock climbing in Eldorado Canyon, Colorado. Another climber was on a route just left of me and well above me. When he climbed up onto the belay ledge he accidentally knocked loose several rocks. One rock hit me in the head. Fortunately, I was...
  43. T

    Crash Test Dummy: Head Impact Parameter & Force Estimation

    A typical car with a dummy crashed into a wall, what is a suitable parameter for the head of the crash test dummy(with and without restraints) as a function of time? and how do i estimate the forces acting on the head in the two situations? Thanks a lot :confused:
  44. P

    Solving for Unknown Values in Overlaid Grids

    Hi All, I wonder if you can help me with a little puzzle I'm working on. I'll include a picture for clarity. I suspect that you mathsy types will be able to tell me straight away if this is possible or not, but I just can see the obvious... I have a fine square grid of numbers (blue in...
  45. Ivan Seeking

    Playing With Sounds in Your Head

    http://www.wired.com/news/culture/0,1284,63278,00.html?tw=wn_tophead_1
  46. H

    I can't get it through my head

    Relativity has been so hard for me to understand! One minute, it makes sense, and the next I am lost. I kind of understand how time can go slower based on the view it is taken from, but I can't understand how a person could actually not get older? That is, if the person is going really fast...
  47. P

    What Factors Determine Nipple Head Shape?

    Hi, Just out of curiosity. We all know that women have different nipple heads.(Actually guys do too). What is the key determinant here? From mom? Dad? And is there a majority kind of nipple head for different kind of people? I know asian girls tend to have "petite" nipples and most...
  48. C

    Annoyinlgy easy problem with thermodynamics that I can't get my head around

    I'm just answering a thermodynamics problem of my Physics homework and I just can't get my head around it here. I'll give you the quesion here, and the reason I don't get it is because you're given the mass of the substamnce as opposed to the number of moles etc... The latent heat of...
  49. C

    News Funny: Ku Klux Klan shoots itself in the head

    Natural selection at work: Ku Klux Klan shoots itself in the head Duncan Campbell in Los Angeles Wednesday November 26, 2003 The Guardian The Ku Klux Klan, the white supremacy group notorious for its lynchings of black people and those who favoured desegregation, has scored a...
  50. C

    How Long to Fall from the Leaning Tower of Pisa?

    I need to know where to start, any good books to help out I'm taking a self study course. I have some study guide from Army education center. I am waiting for video course show up. How long would it take for an object dropped from the Leaning Tower of Pisa height 54.6 meters to hit the...
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