Parallel-Axis Theorem
[M | t+ | — ]
The period of oscillation of an object doesn't change for different suspension points, as long as they're the same distance from the COM.
Hula Hoop Rotational Inertia
[M | t | — ]
A suspended hula hoop has the same period of oscillation as a pendulum whose length is equal to the diameter of the hoop.
Tennis Racquet Flip
[M | t | ★★★]
Demonstration of stable and unstable axes of rotation.
Spinning Football/Coconut
[M | t | —]
Preferred axis of rotation for stability.
Rotational Stability
[M | t | —]
A chain or rope (lariat), when rotated fast enough, assumes an axis about which its moment of inertia is maximum.
Angular Impulse
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Wheel is made to rotate by falling weight attached by string.
Tippy-Top
[S/M | t | —]
A top that flips upside down raising its center of gravity and reverses spin.
Rattleback
[S | t+ | —]
This object, when given a spin, seems to defy the laws of angular momentum as it stops spinning, rocks in place, and proceeds to spin in the opposite direction.
Torsion Pendulum
[M | t+ | —]
Determination of the moment of inertia by period measurements.
[In-Depth Description]
Yo-yo
[L | t | ★★]
A very large cable spool (or smaller version) is made to roll in either direction or slide, depending on the angle of pull; action of a torque.
[In-Depth Description]
Which Way Will the Bike Move?
[M | t | —]
A puzzler concerning torques - pull on a rope attached to the pedal and figure out the consequences.
Rolling Down an Incline
[L | t+ | ★★★★]
Various objects are raced down an inclined plane to verify the effect of their moments of inertia.
Torque Stick
[M | t | ★★]
Have students literally feel the increase in torque as the lever arm is increased.
Rotating Rod
[M | t | —]
A rod with adjustable weights (moment of inertia) is made to rotate by a falling weight attached to the axle via string.
Center of Percussion
[M | t+ | ★★]
The motion (or lack of motion) of the suspension point of an object is observed when the object is struck a blow.
[In-Depth Description]
Breaking Broomstick on Wineglasses
[M | t+ | —]
Two wineglasses support a broomstick which is given a swift blow with a pipe. The broomstick, but not the glasses, breaks.
Falling Faster than 'g'
[M | t | ★★]
Allow a stick to rotate under the force of gravity and the free end will accelerate at a rate greater than g. Relation between angular acceleration and linear acceleration seems to give free-fall paradox.
[In-Depth Description]
Contact Us
Mailing Address: Lecture Demonstration Services, Science Center, Rm B-08A, 1 Oxford Street, Cambridge, MA 02138
Campus Location: Science Center B-08A | Tel: (617) 495-5824 | Email: scidemos-at-fas.harvard.edu