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. [1] Various people have attempted to determine whether there is an actual tendency for bread to fall in this fashion, with varying results.
Written accounts can be traced to the mid-19th century. The phenomenon is often attributed to a parodic poem of James Payn from 1884: [2] [3]
I never had a slice of bread,
Particularly large and wide,
That did not fall upon the floor,
And always on the buttered side!
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). [4] 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. [5] [6] [7] A study on this subject by Robert Matthews won the Ig Nobel Prize for physics in 1996. [8] [9]
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. [10] However, if the table is over 10 feet (3.0 meters) tall, the toast will rotate a full 360 degrees, and land butter-side up. [11] 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. [4]
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.". [8] For this work Mattews earned the 1996 Ig Nobel Prize in physics. [12]
The added weight of the butter has an effect on the falling process, [13] since the butter spreads throughout the slice. [4] 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. [14]
Sometimes the toast falls butter up. The Wise Man of Chelm figured the reason for this long time ago:
A young housewife living in the town of Chełm had a very strange occurrence. One morning, after buttering a piece of bread she accidentally dropped it on the floor. To her amazement, it fell buttered side up. As everyone knows, whenever a buttered piece of bread is dropped on the floor, it always falls buttered side down; this is like a law of physics. But on this occasion it had fallen buttered side up, and this was a great mystery which had to be solved. So all the Rabbis and elders and wise men of Chełm were summoned together and they spent three days in the synagogue fasting and praying and debating this marvelous event among themselves. After those three days they returned to the young housewife with this answer: "Madam, the problem is that you have buttered the wrong side of the bread." [15]