Buttered toast phenomenon

The buttered toast phenomenon is an observation that buttered toast tends to land butter-side down after it falls. It is used as an idiom representing pessimistic outlooks. Various people have attempted to determine whether there is an actual tendency for bread to fall in this fashion, with varying results.

Origins
Written accounts can be traced to the mid-19th century. The phenomenon is often attributed to a parodic poem of James Payn from 1884:

In the past, this has often been considered just a pessimistic belief. A 1991 study by the BBC's television series Q.E.D. found that when toast is tossed into the air, it lands butter-side down just one-half of the time (as would be predicted by chance). However, several scientific studies have found that when toast is dropped from a table (as opposed to being thrown in the air), it more often falls butter-side down. A study on this subject by Robert Matthews won the Ig Nobel Prize for physics in 1996.

Explanation
When toast falls out of one's hand, it does so at an angle causing the toast to rotate. Given that tables are usually between two and six feet (0.7 to 1.83 meters), there is enough time for the toast to rotate about one-half of a turn, and thus lands upside down relative to its original position. Since the original position is usually butter-side up, the toast lands butter-side down. However, if the table is over 10 ft tall, the toast will rotate a full 360 degrees, and land butter-side up. Also, if the toast travels horizontally at over 3.6 miles per hour (1.6 m/s), the toast will not rotate enough to land butter-side down.

Professor Robert Matthews argued that the phenomenon is ultimately based in the fundamental physical constants. His reasoning was as follows. The height of the table from which a toast usually falls is directly related to the height of humans. Matthews proceeds to deduce the limits for a safe average human height from a simple chemical bond model: if a skull is higher than three meters from the ground, then a fall will lead to its fracture due to fracture of the chemical bonds after its acceleration under the Earth gravity. And here are the physical constants in question, quoting professor Matthews: "the electromagnetic fine-structure constant - determines the strength of the chemical bonds in the skull, while the second - the gravitational fine-structure constant - determines the strength of gravity. Finally, the so-called Bohr radius dictates the size of atoms making up the body.". For this work Mattews earned the 1996 Ig Nobel Prize in physics.

Other factors
The added weight of the butter has an effect on the falling process, since the butter spreads throughout the slice. A piece of toast has inertia as it flips towards the floor, preventing its spin from stopping easily; it is usually only stopped by hitting the floor. This moment of inertia is determined by the speed at which the toast is flipping, combined with the size and mass of the toast. Because most toast is relatively uniform, they often land in a similar manner.

Jokes
The buttered cat paradox is a question that asks if toast always lands butter side down and cats always land on their feet, what would happen if a slice of toast were attached butter-side-up to the back of a dropped cat?

A Wise Man of Chelm joke recounts a housewife being amazed at a slice of bread falling buttered side up one morning, contrary to the idiom. After consulting the elders at the synagogue at some length, they conclude: "Madam, the problem is that you have buttered the wrong side of the bread."