Posted tagged ‘Murphy’s Law’


July 10, 2010

Toast – the champion of breakfast foods, the bastion of simple nutrition. A perfect blend of bread (toasted impeccably), butter, and your choice of favourite preserve combine to provide wheat based motivation. To start your day with a toast filled stomach is to march forth into the days beginning unafraid, undaunted. With its solid, wholesome support anything is possible.

Ok, so toast isn’t particularly interesting. It’s crispy bread with a bit of butter on it, it was never going to light up the world. It does have one interesting property, though. It seems to provide a perfect example of Murphy’s law: anything that can go wrong, will go wrong. This is because when dropped, as everybody knows, toast always lands butter side down. If it doesn’t, you must have buttered the wrong side.*

It must be a myth though, mustn’t it? After all, it’s a similar situation to flipping a coin and no one’s claiming that always has one outcome. The claim seemed to be debunked when the BBC show ‘QED’ tossed 300 pieces of toast into the air and found that only 152 of them landed butter side down, obviously proving that it’s all a load of nonsense. We only believe it favours one outcome because of our very selective memories. Job done.

Time to put your feet up

But that wasn’t the end of it. Many people pointed out that the experiment wasn’t really an accurate reflection of dropping a piece of toast in your kitchen. After all, who tosses their toast in the air? If you do, how can you grumble about it landing on the floor? Surely this would only serve to highlight your own ineptitude. Are there hundreds of clumsy and disgruntled toast jugglers out there? I digress.

The stage was set for a mathematician to seize the initiative. Robert Matthews, apparently having nothing better to do, spent a bit of time analysing the dynamics of falling toast (a mathematician’s ability to procrastinate in this manner is, I believe, what truly distinguishes them from other people). He found that the main factor determining which side the toast lands on is the height from which it’s dropped. I’ll explain.

Most dropped toast is the result of it slipping off the plate or tumbling out of your hand. This is where it gets interesting. As the centre of gravity moves outside the support (plate or hand), the toast pivots on the edge and falls off, rotating slowly as it does so. The size and weight of your average piece of toast mean that, in the time it takes to fall from your hand or table, it will have completed half of a rotation. This all amounts to a nicely buttered kitchen floor.

Physics will ruin your breakfast

This is a prime example of gravity and drag forces combining to ruin your morning (aside from making getting out of bed even harder). While you’ll struggle to alter the gravity problem (it’s pretty constant on the Earth’s surface, and the Martians only do cereal) you can change a few other factors.

Extremely thick slices (probably about loaf size), for instance, won’t rotate as quickly. You could also limit the amount of rotation by pushing the toast off the table with force or dropping it evenly. Alternatively, Matthews predicted that toast falling from a height of about 8ft should undergo one full rotation, landing acrobatically on its non-buttered side. As you can tell, mathematician’s are only interested in highly practical solutions.

Not content with the theory (and perhaps not satisfied with his demonstration of the fact mathematicians have far too much time on their hands), he enlisted the help of 1,000 schoolchildren to drop over 20,000 pieces of toast. The results? 62% of the toast landed face down. When the toast was dropped from a height of 8ft, however, it landed face up 53% of the time. Hurray for maths!


So, looking to keep the dog hair off your beautifully crafted meal? Simply butter your loaf, take it to your 8 foot table and give it a good whack. You’ll never have to worry about spoilt toast again.

*Full credit to Ian Steward in his ‘Hoard of Mathematical Treasures’, I loved that joke.

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