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==Size and materials==
[[File:Celt with weights of gemstone turtles-01.jpg|thumb|200px|Carved wooden rattleback]]
While rattleback [[artifact (archaeology)|artifact]]s are described as stone with various measurements, most which are sold currently as novelty puzzles and toys are described as plastic with measurements of 3.75 inches long x 0.75 inches wide x 0.4375 inches high. Carved wooden rattlebacks are described with a measurement of 5.5 to 6 inches in length. One plastic rattleback made and sold by Charles W. Sherburne is described as 12 inches in length. Glass rattlebacks, and those made of spoons, <ref>http://www.exo.net/~pauld/TomTits2000/europetrip/technorama%20lecture/technoramalecture.html</ref> are described as being tested with unreported measurements. Larger rattlebacks (up to 8 feet long and 16 inches wide) are made on request by Emmanuel Peluchon for science museums.<ref>{{cite web|url=http://boisselier.ca/en/products-page/curiosities/|title=Rattlebacks, puzzles and musical tree by Emmanuel Peluchon|website=boisselier.ca}}</ref>
Two rattleback design types exist. They have either an asymmetrical base with a skewed rolling axis, or a symmetrical base with offset weighting at the ends.
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The amplified mode will differ depending on the spin direction, which explains the rattleback's asymmetrical behavior. Depending on whether it is rather a pitching or rolling instability that dominates, the growth rate will be very high or quite low.
This explains why, due to friction, most rattlebacks appear to exhibit spin-reversal motion only when spun in the pitching-unstable direction, also known as the strong reversal direction. When the rattleback is spun in the "stable direction", also known as the weak reversal direction, friction and damping often slow the rattleback to a stop before the rolling instability has time to fully build. Some rattlebacks, however, exhibit "unstable behavior" when spun in either direction, and incur several successive spin reversals per spin.<ref>
Other ways to add motion to a rattleback include tapping by pressing down momentarily on either of its ends, and rocking by pressing down repeatedly on either of its ends.
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