What is Clock: Definition and 483 Discussions

CLOCK (Circadian Locomotor Output Cycles Kaput) or Clock is a gene encoding a basic helix-loop-helix-PAS transcription factor that is believed to affect both the persistence and period of circadian rhythms.
Research shows that the CLOCK gene plays a major role as an activator of downstream elements in the pathway critical to the generation of circadian rhythms.

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  1. K

    Clock: Rates of Change Problem

    Here's the problem: The minute hand is 8 mm long and the hour hand is 4 mm long. How fast is the distance between the tips of the hands changing at one o'clock? It's from my calculus textbook (Stewart) I want to find how fast the distance changes relative to time, not the angle between...
  2. T

    How Does Light Behave in a Moving Light Clock?

    The two parallel mirrors in the light clock are 1 light year apart, vertically. My reference frame which encompasses this clock, is traveling horizontally. The mirrors are 1cm wide. My reference frame is traveling much faster than 1cm/year. Does the light in the light clock reach the second...
  3. DaTario

    Clock & Entropy: Is it Possible to Build?

    Hi All Does anybody know if there is a clock whose mechanism is based on the increase of the entropy of a given system ? Would it be possible or easy to build ? Best wishes DaTario
  4. N

    Ticking Clock and Pendulumn Thoughts

    So I was sitting on the toilet earlier (not needed, I know lol) and the chord for the bathroom light just happened to be swinging back and forth; I also noticed the clock to be ticking. At one particular moment, the chord for the light was swinging in sync with the ticking of the clock and...
  5. A

    Clock Hands Lengths: Hour 4", Minute 6", Second 7" | 24hr Travel

    The hands of a clock vary in length. If the hour handis 4 inches long, the monute hand 6 inches long, and the second hand 7 inches long, how far does this of each hand travel? and also how many feet does the second hand travel in 24 hours, how many miles? I thought so hard about how to go...
  6. rhody

    Food for thought posts World Clock

    http://www.poodwaddle.com/worldclock.swf" Under menu, you can select; year, month, day, week, now (resets stats to 0) Under "More" category, sobering to watch our US national Debt climb. Under "US Crimes" category, identity theft is the most rapidly growing. Under "Illness" category...
  7. H

    Light clock with something else than light

    I think I understand how the classical thought experiment of the light clock (light bouncing between two mirrors work). The typical explanation that is given is "the stationary observer sees the light travel a longer distance (the diagonal), so since light can't go faster than the speed of...
  8. G

    Town clock seconds hand speed and centripetal acceleration

    1. (a)The speed of the tip of the minute hand on a town clock is 0.00136 m/s. What is the speed of the tip of the second hand of the same length? Answer in units of m/s. (b)What is the centripetal acceleration of the tip of the second hand? Answer in units of m/s2. Homework...
  9. D

    Multiple clock thought experiment

    Consider a large number of clocks each within some apparatus programmed to accelerate away from, remain moving for a time, accelerate toward, remain moving for a time and then return to a point of origin. A similar clock simply remains at that point of origin. The accelerated clocks will reach...
  10. T

    Iodine Clock Reaction Question

    Homework Statement Find the concentration of I- involved in the Iodine Clock Reaction Homework Equations I think this will involve m1v1=m2v2 --- but I am not sure. The Attempt at a Solution We did nine 'iodine clock' reactions to demonstrate chemical kinetics. I'll use the...
  11. G

    Exploring Gravity-Independent Pendulum Clock Possibilities

    Hey I asked myself whether there are any possibilities to construct a pendulum clock, which period is independent of the acceleration of gravity, which may differ at different places, or the extension of the pendulum lenght, that is caused by different temperatures?
  12. B

    Exctract clock information from a given binary graph

    Homework Statement I've got a manchester encoded binary data. The question reads, Determine the beginning and end of bit periods (i.e. extract clock infromation and give the data data sequence How do I do this? I think its a simple question but I am having difficult because i don't know...
  13. Y

    Clock rates and effective ptotential.

    Clock rates and effective potential. This is subject that came up in another thread that was getting "off topic" so I decided to start a new thread. I quoted some formulas that I had informally derived (so they might be wrong) for the relative rates of moving clocks in a gravitational field...
  14. L

    Spread spectrum clock generator

    I was reading an article on spread spectrum clock generator here - http://www.maxim-ic.com/app-notes/index.mvp/id/1995 Wouldn't spreading the frequency from the center frequency affect the data transfer? In case of a CPU, the speed would vary too. I understand spread spectrum in...
  15. M

    BCD switches as a clock source

    Can anyone please explain to how one can use a set of BCD switches on a PCB and use them as a clock source? Thanks.
  16. fluidistic

    Special relativity, delay of a clock in a plane

    Homework Statement A plane is moving at 600m/s with respect to the ground. According to clocks on the ground, how much time would it take so that the plane's clock is delayed by 2 microseconds? Homework Equations Lorentz transformations.The Attempt at a Solution Let O be a reference frame on...
  17. G

    Revisiting the Flaws of the Light Clock in Special and General Relativity

    Why "light clock" is flawed. I have been considering this thought experiment for some time, and the principle seems "broken". I'm wondering if by playing devil's advocate you can show me what is going wrong. -In SR, the light clock was used to predict time dilation in a "moving" object...
  18. B

    Relativity train and clock synchronization

    I'm trying to understand the relativity train thought experiment. One of the key concepts seems to be that the clocks at the front and back of the train are "synchronized" such that the clock at the front of the train is running slightly behind the clock at the back of the train (as seen by an...
  19. M

    Clock Reaction Inconsistency ?

    Hello, I have recently been conducting a Clock reaction but has come up with a few inconsistency's. The aim is to measure the effect of verying amounts of catalyst on a clock reaction rate. The rate in turn is measured by a colorimeter. I started out by doing an initial experiment by adding...
  20. C

    The Collision Clock Experiment

    This is a thought experiment that best depicts my issue in understanding special relativity, particularly the congruency of the velocity addition and velocity subtraction formula with other aspects of the theory. This experiment consists of two clocks; clock A and clock B. Clock A...
  21. I

    Does light must be wave-like in Einstein mirror clock thought experiment?

    Hi, In attempt to understand SR, a moving mirror clock is often given as part of a thought experiment, which leads to the dismissal of absolute time. To save people reading, the short version of my question is this: This experiment assumes light is wave-like, right? The long version of...
  22. A

    Grandfather Clock - How to Make 1 Second?

    Homework Statement see attachment, i need to know is it 2\theta or 4\theta to make to 1 second on grandfather clock??
  23. N

    Circular Motion on a Clock Question

    Homework Statement A watch has a second hand 2.0cm long. a) Compute the speed of the tip of the second hand. b) What is the velocity of the tip of the second hand at 0.0 seocnds? At 15 seconds? c) Compute its change in veloicty between 0.0 and 15 seconds. d) Compute its average vector...
  24. C

    Clock in isotropic gravitational field

    1. How would clock in isotropic gravitational field, for example at centre of earth, tick compared to the clock at surface of earth? 2. How would clock in the center of Earth tick compared to the clock at center of sun?
  25. A

    Solving the Clock Hands Problem: Find All Opposite Times

    Here's a cool problem. I thought I came up with it, but it turns out it's been a Google/Microsoft interview question. The solution is pretty cool. Name all the times in a day when the minute hand is exactly opposite the hour hand of a clock. Or you could do the similar problem, name the...
  26. D

    What is the relationship between latitude and the accuracy of an atomic clock?

    Atomic clock should record different time depending on their geo location: different latitude -> different rotation speed. Question: The most precise time on Earth - where is it valid? On what Latitude?
  27. M

    Slit interference pattern depends or whether there is a clock in the room?

    Below is a question (paraphrased) which I addressed to two physics lecturers on the subject of slit diffraction. The problem I have is that answer I received from them sounds so ridiculous and impossible that I find it difficult to accept. I asked the question independently to both lecturers...
  28. L

    How to supply Serial Clock Input into an audio-ADC IC?

    Hi seniors, I am struggling something with my audio ADC. I bought AD7811 from farnell, which is an ADC to convert my analog data into digital. But at this stage, i found that a SERIAL CLOCK INPUT is needed to supply into the IC. However, I m wondering what exactly the clock i should...
  29. T

    I don't understand why your clock slows down

    I've managed to grasp general theory of relativity pretty well but I'm stumped on special theory. I understand nothing can travel at the speed of light, and that the speed of light is always constant. So the closer you get to catching the speed of light, it still looks like it's beating you...
  30. A

    Unlocking the Mystery of Soda Powered Clock

    Homework Statement My teacher used soda to power up a clock. He used a magnesium and copper wire, and soda (sierra mist) I have to explain why and how this happened. Homework Equations n/a The Attempt at a Solution My teacher said it had something to do with...
  31. A

    Big Ben's clock - angular speed problem

    Homework Statement Find the angular speed of the minute hand and the hour hand of the famous clock in London, England, that rings the bell known as Big Ben Express your answers using three significant figures separated by a comma. Homework Equations The Attempt at a Solution...
  32. J

    Designing a clock, stuck on gear reductions

    A few weeks ago, I decided to challenge myself, and design a wooden pendulum clock. It's been loads of fun, especially the hard parts. One such hard part prompted me to make this thread. Here is the problem: Like any regular clock, The hour, minute and second hands are on the same axis...
  33. pellman

    How do we determine one clock is better?

    A pendulum is a better clock than the solar day. The duration of the solar day varies from day to day. But how do we know this except by comparing it to another clock such as the pendulum? How do I know it is not the pendulum which varies from day to day and the solar day is constant? Is...
  34. G

    Iodine Clock Collision Theory Basic Question

    Hey guys. Any chemistry experts around? I just did Persulfate variation of the iodine clock experiment. http://en.wikipedia.org/wiki/Iodine_clock_reaction According to collision theory explained on this page, molecules need to hit each other in certain positions to react. Which molecule...
  35. R

    Light clock moving to demonstrate time dilation

    Hello all, having decided that I wish to apply to Oxford to study Physics (as well as Imperial and, I am still considering Natural Sciences at Cambridge), I have been informed that extra reading and independent study would be advised, so I'm delving into the world of relativity (I'm a first year...
  36. marcus

    Beyond the standard glosses of QM (the realistic clock interpretation)

    We've been watching this development taking shape ever since the tentative Gambini Pullin papers about it in 2006. It represents a fundamentally new way to address the problem of interpreting Quantum Mechanics. One person who worked on this back in 2006, with Gambini and Pullin, used to post...
  37. P

    Exploring Cesium Atomic Clock Functionality

    Can anyone recommend me some papers explaing how cesium atomic clock works?
  38. U

    AM transmitter from clock oscillator

    I am having to ask this from lack of electronic components in my area, so, I want to ask if it is possible to make an AM transmitter (short range) using a clock oscillator? I believe it might be possible, but as the crystal is 32768 Hz, it makes sense to ask, what kind of receiver set should I...
  39. R

    Atomic Clock Reveals Slowing of Time Predicted by Einstein

    An article in Wired concerning a new atomic clock has as part of its lead sentence "The new timekeeper could one day ... detect the slowing of time predicted by Einstein’s theory of general relativity." See http://www.wired.com/wiredscience/2010/02/quantum-logic-atomic-clock/#ixzz0f1IPhJLR...
  40. BobG

    Start Your Clock Business with Roman Numerals

    You decide to start a business selling clocks. http://www.sjs.net.au/pics/1/1962b.jpg You decide Roman numerals make a clock look a lot more stylish and that all of the clocks you sell will use Roman numerals. In the interest of efficiency, you need a single mold that will create all...
  41. M

    Clock Hands: 180 Degree Angle in 24 Hours

    Homework Statement Hi , How Many Times in A day 2 of 3 clock hands makes the angle of 180 degree with each other ?
  42. ThomasT

    Clock postulate and differential aging

    In a recent thread about differential aging in the archetypal twin scenario, I suggested that the periods of oscillators are affected by accelerations, or in other words that a clock's tick rate is affected by changes in its speed. This statement was disagreed with by some, who said that it...
  43. russ_watters

    News Doomsday Clock at 6 Minutes to Midnight

    CNN has an article saying the Bulletin of the Atomic Scientists has dropped their doomsday clock back 1 minute to 6 minutes to midnight. http://www.cnn.com/2010/US/01/15/doomsday.clock/index.html?hpt=Sbin The closest it has been is 2 min, in the 1950s and the furtherst is 17 minutes in the...
  44. L

    Alarm Clock (Finding the Constant)

    Homework Statement This is for my personal experiment for the school. I have been thinking of doing an experiment with my alarm clock. This alarm clock is one of thoes ordinary ones where you have to rotate the spring? and it rotates the gear so the medal rod at the tops moves left and right...
  45. DaveC426913

    Where to Find a 24-Hour Wall Clock for Easy Timekeeping Across Timezones

    I'm looking for a clock that tells 24-hour time. I want a clock that I can set to New Zealand time, which is 15-hours ahead of EST. Wait! Before you point me at one of a zillion 12-hour clocks with a second set of numbers from 13:00-00:00 on them: - a 12-hour clock with a second set of...
  46. H

    Clock problem involving displacement

    Homework Statement the minute hand of a wall clock measures 10 cm from its tip to the axis about which it rotates. the magnitude and angle of the displacement of the tip are to be determined for three time intervals. what are a) magnitude and b) angle from a quarter after the hour to half...
  47. Grimble

    Why does Einstein say that a clock slows when it is moving?

    In http://www.bartleby.com/173/12.html" Einstein says the following: But what is he saying here? That 1 proper second in the reference frame K is equal to gamma proper seconds in the moving frame K0, leading to the conclusion that the seconds in K are larger than the seconds in K0 and...
  48. B

    When Will Google's Countdown Clock Reach Zero?

    The countdown clock appears when you click on the "I'm Feeling Lucky" button on the search engine's homepage. What is this all about?
  49. B

    How Much Time Does a Shortened Pendulum Clock Lose in 24 Hours?

    Homework Statement Pendulum clocks are typically made so the period of the pendulum is 1 second or 2 seconds, but they don't have to be. Suppose a grandfather clock uses a pendulum that is 85 centimeters long. The clock is accidentally broken, and when repaired, the length is shorter by 2.0...
  50. M

    Grandfather clock torque homework

    Homework Statement A 55 g mouse runs out to the end of the 17cm long hand of an old grandfather clock when the clock reads 10min past the hour. What torque does the mouse exert about the rotation axis of the clock hand. Homework Equations Torque=rFsin(theta) The Attempt at a...
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