How long would it take to find a needle in a haystack?
A needle in a haystack is the textbook hopeless search. But how hopeless exactly? We worked it out using the haystack from our game HALM: 20 million straws, one needle.
The assumptions
- The pile has 20 million straws. Real haystacks are smaller or bigger depending on size, but the order of magnitude fits.
- You check one straw per second: pick it up, look, put it away. That is already quite quick.
- The needle sits somewhere at random, so on average you find it after half the straws.
The math
On average you have to check 10 million straws. At one straw per second that is 10 million seconds.
- Non-stop, day and night: about 116 days, almost four months.
- 8 hours a day: about 347 working days, almost a year and a half of full-time work.
- Worst case the needle is the very last straw. Then it is twice as long, almost three years of working time.
In short: by hand, a needle in a haystack is not an idiom, it is a career change.
How to do it faster
Luckily you don’t have to check every straw. The needle is metal, and that changes everything:
- A strong magnet pulls the needle out of the hay when you get close enough. You comb through the pile instead of checking straw by straw.
- A metal detector tells you where to look. Instead of digging through the whole pile, you only dig where it beeps.
- A sieve separates heavy metal from light hay. With enough people and time this is surprisingly fast.
- Burning the pile is the brute force option: the hay is gone, the needle stays. Then again, the hay is gone too, and the farmer probably wanted to keep it.
That is exactly how HALM works
In HALM you start like the math above: bare hands, 10 straws per grab. Every load of hay you deliver earns money, and with that money you buy exactly the shortcuts from above: pitchfork, shovel, metal detector, later farmhands, conveyor belts and machines. Almost three years of work turn into a few hours of play. How fast can you find all five needles?
Questions
How long does it take to find a needle in a haystack?
With 20 million straws and one straw per second, about 116 days on average without breaks, or almost a year and a half at 8 hours a day.
What is the fastest way to find a needle in a haystack?
Use tools that react to metal: a metal detector shows the spot and a strong magnet pulls the needle out.
How many straws are in a haystack?
It depends a lot on the size. A big pile can have millions of straws. In the game HALM it is 20 million.
Want to try it yourself? HALM runs free in your browser on Mac, PC and phone, no download and no sign-up.
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