Buttered toast phenomenon

The buttered toast phenomenon is the tendency of buttered toast to land butter-side down after it falls. This has been considered to be a representation of pessimistic ideas. Murphy's law takes credit for this, but science and physics proved it happens in the right environment.

The phenomenon is said to be an old proverb from "the north country." Written accounts can be traced to the mid-19th century. The phenomenon is often attributed to a parodic poem of James Payn from 1884:

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 study by the BBC's television series Q.E.D. found that when toast is thrown in 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 does fall butter-side down. A study by Robert A J Matthews won the Ig Nobel Prize in 1996.

When toast falls out of one's hand, it does so at an angle, by nature of it having slipped from its previous position, then the toast rotates. Given that tables are usually between two and six feet (0.7 to 2 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 feet (3 meters) 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. In fact, the phenomenon is caused by fundamental physical constants.

The added weight of the butter has no effect on the falling process, since the butter spreads throughout the slice.

"The mass of butter added to toast ( ~4g ) is small compared to the mass of the typical slice of toast (~35g), is spread thinly, and passes into the body of the toast. Its contribution to the total movement of inertia of the toast and rotational dynamics, thus its effect on the toast is negligible” Tumbling toast, Murphy’s Law and the Fundamental Constants, by Roberts A J Matthews.

The following findings are from Mythbusters:

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Wikipedia