## How much is a billion?

We are used to hearing large numbers such as a billion mentioned frequently on the news (often when the budget deficit is mentioned). However, it's very difficult to picture what these huge numbers really mean.

Working out how big these numbers are is made harder because, traditionally, the United States and the United Kingdom meant different amounts when each one talked about a billion.

The old UK meaning of a billion was a million million, or one followed by twelve noughts (1,000,000,000,000).

The USA meaning of a billion is a thousand million, or one followed by nine noughts (1,000,000,000).

Increasingly in this country we are using the USA meaning of a billion for these big numbers, and a trillion for the old UK meaning of one followed by twelve noughts. The UK government has been using the American meaning of billion since 1974 for the numbers it gives out.

Even the smaller American billion is a huge number, and hard to imagine, so we have tried to find a way to show how big it is using some every day objects. The object we chose was a cheesy wotsit.

We then wanted to describe how much space a billion cheesy wotsits would take up, so we decided to work out how many white vans it would take to transport this many wotsits if we just filled up the back of the vans with loose wotsits. (You'd need more vans if the wotsits were bagged, because you'd have to allow space for the packaging.)

(For any Americans reading, a cheesy wotsit is like a cheeto).

So what's the answer?

We estimate that you would need at least 772 white vans to move 1 billion wotsits.

How did we work this out? We had to guess a couple of things.

First, we had to work out roughly how much space there is in the back of a white van. We think that this is slightly less than twelve cubic metres.

Then, we measured a few wotsits, and decided that they were roughly four cm long, and roughly one a half centimetres in diameter, so we could work out how much space each one took up.

Doing this we realised that most wotsits aren't straight, but usually curved, and so wouldn't pack together very well. We guessed that a wotsit needed about half its own size again when packed together, to allow for the spaces.

Dividing the space inside the van by the space needed for one wotsit told us how many wotsits we could get in a van (slightly less than 1.3 million), and dividing one billion by this number gave us just over 772 white vans full of wotsits.

We have seen other sites trying to visualise large numbers using rice rather than wotsits. However, we worked out that filling the back of a white van with rice would probably break the axle of the van.

Since we wrote this, we have had the following simple and effective example contributed by Jess Monck.

1 million seconds is about 11.6 days

1 us billion seconds is about 32 years

1 uk billion seconds is about 32,000 years