The Incredible Spill Not

May the Centrifugal Force be With You!

The Spill Not provides the ultimate solution for carrying cups of hot coffee and other beverages for long distances without ever having to worry about spilling them again.

A simple hanging saucer consisting of a base and loop handle, the Spill Not is not only incredibly effective, but fun to use.

With the Spill Not, the liquid in the cups does not spill or slosh in the cup, and the cup doesn’t slide when carried or swung around. This is because the loop handle is very flexible and cannot deliver a lateral acceleration to the cup, which is usually what makes beverages spill from an open container not tipped.

(Please Note: coffee mug is not included)

The fundamental concepts of Newtonian physics explain why this amazing tray can be used to carry and swing a full open cup of coffee (or any liquid) with no spills!Durable yet elegant hanging tray for a single open beverage that can be swung all around with an incredibly small risk of spilling. Amazingly effective!The cool physics is that the liquid does not spill or slosh in the cup and the cup does not tend to slide on the Spill Not as it is carried, even if it is swung all around. Why not? The answer is that the loop handle (let’s think of it as a ‘thread’) is very flexible and cannot deliver a lateral acceleration to the cup, which is what usually makes liquid spill from an open container that is not tipped.

That is, when people spill coffee while walking with an open mug, the liquid ‘sloshes’ out due to a horizontal acceleration of the cup. When the cup is accelerated, it applies a horizontal force to the liquid. The liquid, of course, has no fixed shape so the horizontal force causes a build-up of liquid at the side of the cup that is applying the force. If the build-up is higher than the side of the cup, there is a spill. If the force ceases without a spill, gravity pulls the liquid back down and the momentum of this flow causes a smaller build-up of liquid on the other side of the cup. With no additional forces, the oscillations eventually die down and equilibrium is reached with the surface of the liquid flat and level. However, when walking with a cup of liquid, a person may inadvertently apply horizontal accelerations to the cup at an interval that matches the resonant frequency of the oscillations described above. When this occurs, the amplitude of the oscillations can increase, causing the liquid to spill even if the person carrying the cup has not applied any single particularly large horizontal acceleration to the cup.

What happens when a person applies a horizontal acceleration to the handle (upper end of the ‘thread’) of the Spill Not? Because the thread is very flexible, no lateral force is applied to the saucer and thus no lateral force is applied to the cup. Instead, as the top of the thread moves horizontally, the saucer and cup swing up slightly in the opposite direction and the thread exerts a force on the cup through the saucer causing acceleration in the only direction in which the thread can exert a force, toward the upper thread end that is held. The direction of this force is parallel to the sides of the cup (by the Spill Not design), and thus does not tend to cause sloshing. At the same time, gravity pulls down equally on the saucer, cup, and liquid molecules in the cup, counter-acting the swing caused by horizontal acceleration of the upper thread end without causing sloshing.

More generally, swinging does not tend to cause the cup to slide off the saucer or liquid to slosh in the cup because the only force acting in a direction that is not parallel to the sides of the cup is the force of gravity, and gravity is equally accelerating all molecules of the saucer, cup, and liquid in the cup.

If the Spill Not is swung all the way around in a loop such that the cup is upside-down at the top of the arc, the liquid does not pour out of the cup due to the pseudo force, centrifical force, which acts in the opposite direction as gravity when the cup is at the top of the arc.

Interestingly, for the webbing loop handle to lie flat and have no twists, it must be a Mobias strip (the strip is sewn together on the standard Spill Not handle for ease of use)! Warning- If bumped, spillage may occur. Not for use with liquids that are hot enough to scald. Not recommended for moving vehicles. Not for children under 3 years of age.

***Please note, if the Spill Not is swung with an open beverage, there is a risk of spillage.