Kitchen Science Experiments

Butter Side Down

Sun, 16th Dec 2007

Listen Now    Download as mp3 Part 1,2 from the show The Naked Scientists Christmas Special

What you Need

Slice of toast

A slice of toast and something to spread on one side of it.

A table

A table

What to do

Pushing toast of table

Butter the toast

It is generally best to put something on the floor such as newspaper

Push the toast off the table at the sort of speed you might accidentally knock it off while having breakfast.

Which way up does it land?

Repeat the experiment 5-10 times. Does it actually normally land butter side down?

What may happen

 When we tried this we found that the toast landed butter side down six out of six times, although it is just about possible to get it to land butter side up if you push the toast off very slowly.

Toast 0

Toast 1

Toast 2

Toast 3

Toast 4

Toast 5

Why does it happen?

There have been lots of explanations for this problem ranging from bad luck to aerodynamics, but it is actually quite simple. As the toast falls off the table it starts to rotate. The speed of this rotation will depend slightly on how fast you push the toast off the table, but at the sort of speed you normally push things off a table the piece of toast will be spinning at a rate that means it will have turned upside down by the time it hits the floor.

Flash Object

What can you do to make the toast land butter side up?

If on the other hand you knock the toast off the table very fast it will be rotating slowly and can land the right way up.

Flash Object

Or of course you could sit at a higher table so the toast has time to turn all the way over as it falls, there is only one problem, you would have to build the table about 3m high!

Flash Object

Multimedia

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