How Big Is a Million?
In the Thousand, Million, Billion lesson we saw that a million is a thousand thousands, and a billion a thousand millions. It is easy to write the zeros. It is much harder to feel how big these numbers are. "Million" and "billion" sound alike, but the difference between them is enormous. How can we feel it?
Counting seconds
Imagine counting one number every second, without stopping to eat or sleep:
- to a thousand takes about 17 minutes;
- to a million takes about 11 and a half days;
- to a billion takes almost 32 years.
So a billion is not a bit more than a million. If counting to a million took one day, counting to a billion would take nearly three years.
Stacking paper
A sheet of printer paper is about a tenth of a millimetre thick. Make a stack:
- a thousand sheets: about 10 centimetres - two packs of paper;
- a million sheets: about 100 metres - as tall as a building of about 30 floors;
- a billion sheets: about 100 kilometres - higher than aeroplanes fly, right up to where space begins.
Back to the Sun
Now try the number from the start of the last lesson: the Sun is about 150 million kilometres away. A car on a motorway goes about 100 km in an hour. If you could drive to the Sun without ever stopping, it would take about 170 years.
That is why big numbers matter for measuring the world. Without them, we couldn't even say how far away the Sun is.
Try it at home
- Time yourself counting from 1 to 100 out loud. How long would a thousand take at that speed? (Multiply by 10.)
- Look up how many people live in your city, and in your country. Is each number in thousands, millions or billions?
Words to know
No new words in this lesson - just a better feel for the ones from the last lesson.
Big idea
A million seconds is about 11 and a half days, and a billion seconds almost 32 years. A billion is a thousand times a million, so the two are very far apart, however alike they sound.