Tippe Top
#Presented by Shounak and Sankarsan Datta
Introduction
#The Tippe Top is one of the most visually baffling objects in classical mechanics. It looks like an ordinary spinning top — a small dome-shaped body with a short stem — but when set spinning on its dome, it does something that seems to defy both intuition and gravity: it flips itself upside down and ends up spinning on its stem instead.
In this demonstration, the top is placed dome-side down on a smooth plate and given a spin. Within a few seconds, it begins to tilt, continues to rise, and completes a full inversion — its centre of mass actually climbing higher as it flips. The result looks like the top is gaining energy from nowhere, making it a perfect conversation starter about what angular momentum and friction can do together, and about why apparent violations of common sense are so often the key to deep physics.
Precautions
#Spin the top on a smooth, level surface such as a plate or a glass sheet. The flipping behaviour requires a low-friction surface — rough surfaces stop the top before it can invert. Do not spin it too fast or it may skitter off the plate.
Materials Required
#- A Tippe Top (dome-shaped body with a short stem)
- A smooth, flat plate or glass surface to spin it on
Science Behind It
#The Tippe Top's inversion is driven by the interplay between angular momentum, gyroscopic precession, and friction. The top's centre of mass is deliberately offset — it sits slightly above the geometric centre of the dome. When the top spins, the contact point between the dome and the surface experiences friction. This frictional force, combined with the spinning motion, produces a torque that causes the rotation axis to precess — that is, to slowly tilt.
As the axis tilts, the stem begins to swing downward. The top progressively inverts until the stem is pointing down and the dome is in the air, at which point the flipping stops. Remarkably, the centre of mass is now higher than it started, which seems to violate energy conservation. The resolution is that the rotational kinetic energy of the top has decreased: friction dissipates energy during the flip, and this energy loss more than pays for the rise in potential energy. The total mechanical energy decreases, as it must for any process involving friction.
The Tippe Top is a beautiful example of how angular momentum is a vector — one that can be steered by torques — and how friction, usually cast as the villain that slows things down, can instead act as the engine that drives a spectacular reorganisation of motion.