Mechanics:
Tippy Top

PIRA Class: 1Q60.30

Purpose:
A surprising demonstration of rotational instability and the effect of frictional torque on a top with a truncated sphere shape.

Description:
Spin the top with the stem facing up and the stem will gradually tilt downward until the top flips completely over so that it is spinning on its stem. A football spun with the long axis horizontal displays a similar behavior.

NOTE: When the top flips over its gravitational potential energy increases, this is accompanied by a decrease in rotational kinetic energy. The direction of the top's angular momentum vector (relative to the ground) is the same before and after the top inverts.

Equipment:
Tippy Top (we have several in a Ziplock bag)

Location:
Shelf 134

Extras:

TPT article providing a quick discussion of the Tippy Top

AJP article providing a thorough analysis of the Tippy Top