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This is actually funny but science is a crazy thing and that's why am not so surprised.

Have you heard aboutsomeone lying on a bed of nails?
It's not magic.

It's science and I'll show you about it here.

How nails work
Look closely at a nail and you'll see it has a sharp point at one end and a big flat head at the other. Thumbtacks (drawing pins) are just the same.

The two different ends of a nail are designed to make the force you apply have a bigger effect. When you hit a nail with a hammer, you apply a certain amount of force to the bigger end.

At this end of the nail, your hammering force is working over quite a large area. That same force travels down the nail to the opposite end. Here, the nail comes to a very sharp point. So the same force is now acting over a much smaller area. The effect a pushing force has on something is called its pressure.

The pressure of a force is the size of that force divided by the area over which it pushes. If the same force presses at both ends of the nail, but one end (the sharp end) is much smaller than the other, the pressure at that end is much greater.

So a nail or drawing pin actually increases the pressure of your pushing force. That makes it easier for the nail or pin to enter the wall.

Working together, the flat end and sharp point of a drawing pin can magnify the pressure you apply by over 100 times.

How does a bed of nails work?
A bed of nails is made of several thousand nails hammered through a large wooden board. All the nails are extremely sharp. If you tried to stand or lie on just one nail, and you could balance on it without falling off, the nail would pierce your skin instantly and hurt you very badly.

You might think thousands of nails would do thousands of times more damage—but you'd be wrong!

Think about the forces that are involved when you lie across a bed of nails. There's your weight, which pulls you downwards because of gravity. The only thing supporting your body is the nails. So your weight must push down on the nails.

Since your body doesn't go anywhere, there has to be another force keeping it still. It turns out that the nails push up on you with the same force as your weight pushing down.

Your weight pushes down not on one nail but on several thousand. So the force acting on each nail is your weight divided by several thousand. Suppose a person weighs about 70 kg and lies down on 3500 nails.

The average weight on each nail is about 20 grams—roughly the same as a pen. A weight of 20 grams is just not enough to push the nail through someone's flesh.

That's why it's safe to lie down.
What does this tell us about normal beds?
If for "nails" you read "springs," you'll see straight away why a bed with many springs is more comfortable than one with fewer: your weight is more evenly distributed over more supporting points so the force acting on each part of your body is less.

You feel more comfortable and you sleep better.

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