## 9.Building Pyramids: Number of People

**Building Pyramids: Number of People**

Many hypotheses about the way the great pyramid was built suggest vast armiesof labourers working for 10s of years, or impossible machines that defy everydemonstration and measurement of the physical world.

Most of these hypotheses are based on vivid Victorian imaginations thathave not been properly scrutinised or tested.

## Estimates

The great pyramid is built from aproximately 2 million blocks of stone.Each block averages 0.9m x 1m x 1.2m

This stone has a density of 2.563kg/m^3 (160 lb / cu ft)

So each stone averages 2768 kg (2.5 tons)

## Calculations

Most big building projects, such as building the medieval cathedrals, useda constant, skilled work force over many years. Let us assume that the greatpyramid was no different. So let us assume a fairly constant skilled workforceworking 300 days per year, and a target of 10 years to completion. Thereis no reason to vary the rate of building as the pyramid rises.In 10 years we have 3000 working days.

So each day we need to cut, move and place 2 000 000 / 3000 = 666 blocksper day.

Let us assume 700 blocks per day to allow for some wastage.

I am going to use the figures for cuttingstone by hand provided by the Beer Quarry Caves in Devon UK. Here ittook 10 hours for one man to cut a 4 ton block of stone.

It seems a reasonable deduction that on average 1 man will be expected tocut 1 block of stone of 2.5 tons as his days work - an easy measure of whetherhe has worked well that day!

So 700 blocks per day requires 700 men as cutters in the quarries.

100 men each loading and transporting 7 blocks per day and removing debris.

10 men each preparing 70 saws per day.

If I were building the pyramid I would hope to cut the stone from a quarryfrom a rock face slightly uphill of the building site, even up to 10 milesaway, so that I can build a wooden sledge track with a downhill slope tothe quarry site. Even at that distance a team of one man and a pair of oxenshould haul 3 blocks per day.

So for transport to the building site we need 250 men.

Lifting the stone up the sloping face of the pyramid using the Herodotuslifting engine requires a team of 6 people pulling the levers to lifta block 1m in 10 seconds with an expenditure of 500w of energy each.

If we assume that they are not being flogged to death, take a reasonablerest between each block and we use 10 lifting engines side by side, theneach engine series needs to lift 70 blocks per day.

This is the one area where the workforce has to increase as the pyramidgets higher, because we are using a team of 60 people for every metre itincreases in height, but this is not skilled labour - just pull and releasethe levers, then sit down and rest for 5 minutes.

On the working level we need 100 people to move and place the blocks, 10people to move and rebuild the sledge tracks and perhaps another 20 peopleto lower the sledges back to the ground - but the sensible way would be tolower the sledges on ropes attached to the rising sledges, so reducing theenergy required for both operations.

Add another 10 carpenters to maintain the tracks.

Add another 300 people to do all the checking, supervising and procurement

**And we have a grand total of 2000 people to build a pyramid up to the10m level and then an extra 60 people for each metre extra height . **

**Not a vast number!! and far more likely to be specialist workerspaid well on a year round basis. **