# Rattlebacks

(6 reviews)
• Rattlebacks (Set of 5)
Item #: SS-310
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• Rattlebacks (Set of 12 in bulk)
Item #: SS-335
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• Rattlebacks (Set of 30 in bulk)
Item #: SS-323
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A half-ellipsoid object carved so that it will spin in only one direction.

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

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

6 reviews
May 12, 2020
During elearning/distance learning lessons, I would post a discrepant event once a week and the first five students to answer it in detail correctly, received these as a prize. They were thrilled.
Heidi Moreno

0   0

Rattlebacks
Dec 21, 2014
These are great little toys! The rattleback's movement when rotated is unexpected and serves as a discrepant event. I used them this year in an engineering elective and had the students try to make their own rattlebacks with simple materials; they loved it!
Nancy B.

1   0

artifact study
Jul 5, 2014
worked as promised and get for a look at archaeology artifact toy function.
Mary Anne

0   0

Rattlebacks plus extra mile!!!!
Aug 24, 2013
The product I received was exactly what I wanted and expected. My order arrived early which was awesome!!! All of the awesome people who filled my order did so with care and consideration! This I know for a fact because I put some silly instructions for the person filling my order and every one of those silly instructions (as unnecessary as they were) were fulfilled to perfection! Thanks for going the extra ten miles you guys! This was the best Internet order I've ever made because of you guys!
Kevin Babson
Owner Response: Thanks, Kevin! We try!

1   0

How Did That Happen?
Oct 15, 2012
The first comment out of my students' mouths is How Did That Happen? What an awesome discrepant event!
Carson

0   0

Rattleback works great!
May 16, 2012
Great to use for science inquiry activities!
Jane Carter

0   0

### 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.

Suggested Science Idea(s)

3-PS2-2
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.

Q & A