Chance in action

Kia ora! Will the sun come up tomorrow? Will a kiwi ride a skateboard to school? Some things are sure to happen, and some never will. Let's measure chance!

Picture a line from zero to one. Zero means impossible, like that skateboarding kiwi. One means certain, like the sunrise. Right in the middle, at one half, is an even chance.

Between zero and a half, things are unlikely. Between a half and one, they're likely. Rolling a six on a dice? Unlikely. Rolling anything except a six? Likely!

So why is a coin flip an even chance? A coin has two sides, and each one is equally likely. Heads is one out of two: a half. A spinner with four equal parts? Each colour is one out of four.

A dice has six faces, all equally likely. Only one of them is a six, so the chance of rolling a six is one out of six. We write it as a fraction: one sixth. Rolling an even number? Three out of six. That's a half!

But does real life follow the maths? Let's flip a coin and tally the results. Heads, tails, heads, heads. After ten flips, we have seven heads! That's not very even.

So let's keep going. Fifty flips, a hundred, a thousand! At first the results wobble about, but as the flips pile up, the line settles down, closer and closer to one half. After a thousand flips: four hundred and ninety nine heads. Almost exactly half!

So remember: chance goes on a line, from zero, impossible, to one, certain. Equally likely outcomes give us fractions, like one in six. And the more times you try, the closer your results get to the maths.