Over the years there have been many explanations about why toast always lands butter-side down. Most of these reasons involve luck or simply the concept that life (particularly yours) sucks. Like in most cases, there is a simple and logical reason for this phenomenon.
For the purpose of this writing, we will assume references to toast mean buttered toast. There have been almost no reported cases of unbuttered landing butter-side down. There was only one recorded case from ancient Greek writers, but since it involved Zeus it may be discounted as mythology. There were also experiments in France in 1923 where toast had pieces of paper stapled to the side. The papers were marked ?beurre,? French for ?butter?.
We?ll begin with a couple of definitions relevant to the explanation. Toast is a bit of bread where the larger faces are usually without crust. This piece of bread has been exposed to a source of radiant energy for the purpose of carbonizing the outer layer of these crust-less faces in a process called toasting. Toasting gives the bread a distinct flavor, a more rigid surface, and a darker color. Because bread tends to be filled with air pockets, the surface of the toast is very rough.
Buttering toast consist of putting butter, or a butter substitute, onto one toasted face of the toast. The butter is applied and then smoothed over the surface of the toast as evenly as possible to a thickness determined by the person making the toast. (If you?re like me, you like to lay it on thick.) This also changes the flavor of the toast while softening the buttered face. Butter and its substitutes are usually made up of a fatty substance and have a smooth texture.
Some people put things other than butter or butter substitutes. These other things tend to also be smoothed over the toast and tend to be denser than the toast itself. In these cases, this explanation applies equally to why dropped toast will land other-substance-side down. I think I saw a book describing the effort to put a ?Watership? onto toast that ended in similar results.
When you drop your toast, gravity pulls the toast downward. Air resistance works against the falling of the toast. These two force work together to flip the toast around to land with the butter on the floor. There are two components to how this works.
It was mentioned above that the surface of the toast is course and that butter is smooth. Putting butter on the course surface of the toast gives that face a smoother texture than the unbuttered face. The air resistance is greater on the more course face, causing that side to fall more slowly. The buttered side can go through the air more easily and can fall faster and reach the floor sooner.
The butter is also denser than the bread. This makes the buttered side heavier than the non-buttered side. Though this does not directly cause the buttered side to fall faster (science has shown that heavy things do not fall faster than light things though they do put on a better show when landing), it does mean that the denser side can fight the air resistance more effectively.
Combining these two factors you get the cause for your toast to hitting the floor butter-side down. Of course, these are just the major factors; there are still things like gremlins, bad luck, and the fact that your life sucks. The main thing to remember about this, and I say the following mostly for the science fair kids who may want to site this document in their experiments, is that I?ve pretty much just made this up because it amused me. Though the ideas here may seem reasonable (to some people) I have no science to back up any of this. Do not use this information in anything more serious than drunken barroom discussion. You could also use it to mess with the heads of that neighbor kid who is always stoned, but I don?t officially condone drug use.
There you have it, a reason for why toast lands butter-side, jelly-side, watership, or marmalade-side down.
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