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| {{underlinked|date=October 2012}}
| | The name of the writer is Figures. One of the extremely very best things in the globe for me is to do aerobics and now I'm attempting to make money with it. Hiring has been my profession for some time but I've already applied for an additional one. North Dakota is our birth place.<br><br>Here is my web page; [http://riddlesandpoetry.com/?q=node/19209 std testing at home] |
| [[File:Gee-haw whammy diddle.gif|thumb|Spinning gee-haw whammy diddle]]
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| [[Image:GeeHawWhimmyDiddle.JPG|thumb|right|210px|The gee-haw whammy diddle.]]<!-- Deleted image removed: [[Image: Gee-Haw Whammy Diddle.jpg|thumb|right|210px|The gee-haw whammy diddle.]] -->
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| A '''gee-haw whammy diddle''' is a [[Mechanical system|mechanical]] toy consisting of two wooden sticks. One has a series of notches cut transversely along its side and a smaller wooden stick or a [[propeller]] attached to the end with a nail or pin. This stick is held stationary in one hand with the notches up, and the other stick is rubbed rapidly back and forth across the notches. This causes the propeller to rotate. Sometimes also known as a '''[[ouija]] windmill''', a '''hooey stick''' or a '''VooDoo stick'''. The word ''whammy'' is sometimes ''whimmy'' and the word ''diddle'' sometimes ''doodle'', giving it three possible other names, and the ''gee-haw'' may also be dropped.
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| ''[[Gee and haw|Gee-haw]]'' refers to the fact that, by rubbing your finger against the notched stick while rubbing, the direction of the spinning propeller may be reversed. The operator may do this surreptitiously and yell "gee" or "haw" to make it appear that the propeller is reacting to the commands. If you call it a ''hooey stick'', you would yell "hooey" each time you want the direction to change.
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| ==Physical explanation==
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| To observe the effect, the propeller attached to the end of the ribbed stick must not be pinned at its exact [[centre of mass]]. For a functioning whammy diddle, there should be a "preferred" [[angle]] (i.e. when stationary, if the propeller is rotated around its axis and then released, it should return to its lowest-energy [[rest angle]] relative to the ribbed stick.) Rubbing the ribbed stick with another stick along the grooves creates a vertical alternating driving [[force]] <math>F_y</math> acting on the centre of mass of the propeller:
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| :<math> F_y(t) = Y cos(\omega t) </math>
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| where <math>h \omega = 2\pi/T </math> and T is the time taken for the stick to move from one groove to the next; <math>Y</math> is some unknown scaling factor that characterizes the force with which the two sticks are pressed against one another. By rubbing a finger against these grooves on the side, one can also introduce a ''horizonal'' alternating driving force <math>F_x</math>
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| :<math> F_x(t) = X cos(\omega t + \phi) </math>
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| where <math>\phi</math> is a [[phase shift]] (describing the lag time between when the grooves contacts the moving rod, and finger respectively) and, again, X is some unknown scaling factor. Importantly, <math>\omega</math> is the ''same'' frequency, and the two driving forces are said to be [[phase locked loop|phase locked]]. The confluence of two phase matched driving forces in [[Orthogonality|orthogonal]] directions gives rise to a [[rotational force]] on the centre of mass at the propeller end, and thus, rotation.
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| When the operator of the whammy-diddle surreptitiously changes the side at which his/her finger contacts the stick (e.g. by contacting with his thumb instead of his fore-finger, or by changing the side at which a finger contacts the grooves of the base) he or she changes the sign of the phase <math>\phi</math>, and thus reverses the rotation.
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| ==See also==
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| * [[Whirligig]]
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| ==References==
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| * [http://www.mugwumps.com/whammy.htm "Toys, Making a Whammy Diddle"], ''MUGWUMPS'', Vol. 1, No. 6, November 1972.
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| * {{cite journal
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| |last=Aubrecht
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| |first=Gordon J., II.
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| |title=A mechanical toy: The gee-haw whammy-diddle
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| |journal=The Physics Teacher
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| |volume=20 |issue= 9|date=December 1982 |pages=614–615
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| |bibcode=1982PhTea..20..614A
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| |doi=10.1119/1.2341165
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| }}
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| ==Further reading==
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| * Schnacke, Dick. ''American Folk Toys: How to Make Them,'' Viking Press, 1974. (ISBN 0-14-046209-0)
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| {{DEFAULTSORT:Gee-Haw Whammy Diddle}}
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| [[Category:Traditional toys]]
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| [[Category:Wooden toys]]
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The name of the writer is Figures. One of the extremely very best things in the globe for me is to do aerobics and now I'm attempting to make money with it. Hiring has been my profession for some time but I've already applied for an additional one. North Dakota is our birth place.
Here is my web page; std testing at home