Description
A Rattleback is a half-ellipsoid object carved so that it will spin in only one direction. Accidentally discovered by archaeologists, this curious object was first dubbed a celt stone, named after the prehistoric axes and adzes they were studying. Idly spinning one of these ancient tools on the table, these scientists must have been surprised to discover that the seemingly normal piece of carved stone would spin freely in one direction, but would reverse itself if spun in the other direction. ~10 cm (4") long, 2 cm (0.8") wide.
Video
Lesson Ideas
For Physics Teachers
Download the pdf of this lesson!
These half ellipsoid objects are modeled after objects made millennia ago. Archaeologists discovered them with stone axes and adzes and dubbed them 'celt stones.' Soon it was discovered that the stones would spin freely in one direction, but if forced in the opposite direction they begin to oscillate, slow, and then reverse direction.
Place your Rattleback, curved side down, on a flat, smooth surface, like a tabletop, and spin it counterclockwise. It should spin freely. Now try to spin it clockwise. Notice that it begins to wobble and slow then reverses direction.
The Rattleback is shaped much like a canoe, but its keel is not parallel with the rest of the boat. This causes the center of gravity to shift right or left depending on which end of the 'keel' is in contact with the surface it sits on. Try simply setting your Rattleback on a table. Without trying to spin it, press down and release one end. As it rocks, it will begin to spin.
Try your Rattleback on different surfaces. Try attaching small weights or coins to each end. Can your students make a Rattleback from clay or other materials?
Reviews
Sep 11, 2023
Was this review helpful?
May 12, 2020
Was this review helpful?
Dec 21, 2014
Was this review helpful?
Jul 5, 2014
Was this review helpful?
Aug 24, 2013
Was this review helpful?
Oct 15, 2012
Was this review helpful?
May 16, 2012
Was this review helpful?
NGSS
This product will support your students' understanding of the Next Generation Science Standards (NGSS)*, as shown in the table below.| Elementary | Middle School | High School | ||
| 3-PS2-2 Students can make observation and/or measurements of the Rattleback's motion to provide evidence that a pattern can be used to predict future motion. | MS-PS2-2 Students can make observation and/or measurements of the Rattleback's motion in an investigation plan to provide evidence that the change in an object's motion depends on the sum of the forces on the object and mass of the object. | HS-PS2-2 Students can make observation and/or measurements of the Rattleback's motion and then use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the systems. |
MS-PS2-2
HS-PS2-2
Place your Rattleback, curved side down, on a firm surface, like a tabletop, and spin it counterclockwise. It should spin freely. Now try to spin it clockwise. Notice that it begins to wobble and slow then reverses direction.
The Rattleback is shaped much like a canoe, but its keel is not parallel with the rest of the boat. This causes the center of gravity to shift right or left depending on which end of the 'keel' is in contact with the surface it sits on. Try simply setting your Rattleback on a table. Without trying to spin it, press down and release one end. As it rocks, it will begin to spin. Variations: Try your Rattleback on different surfaces. Try attaching small weights or coins to each end.
* NGSS is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, this product.
You May Also Like
-
$19.95 -
$11.95
