The Four Pyramid Building Activities
Left: Modern Egyptians pulling a stone block on a sled, on top of a reconstruction of the roads made by the ancient Egyptians. The roads were made by laying down wooden beams (recycled from boats used to bring some of the stones), and filling the gaps with stone chips and mortar. This was also covered in a layer of stone chips and gypsum (like plaster) to give a solid surface. On top of this, mud was probably used as a lubricant.
The limestone
blocks weighed an average of about 2.5 tonnes, and some were much
bigger. They were quarried nearby and pulled using ropes; perhaps 20 men
were required.
Using a force meter we will see how hard it is to pull
stone on sand. One child will pull while another reads the force meter.
We will write all the figures on the board so the children can draw
their own conclusions.
It should be clear that the blocks were not pulled
across the sand! In fact the Egyptians built sledges, and we will use a
replica on sand to see how much difference this makes. Of course we must
remember that much of the pulling was uphill, as the bocks had to be
taken up the pyramid - when the Great Pyramid was nearly finished, to a height of 146
metres.
Children will see that the benefit of the sledge does not last long, as
the sand gets caught between the beams of wood and slows the sledge down.
In fact the Egyptians had to build special roads, using wooden beams like railway sleepers, filled in with chips of stone and mortar (see photo at the top), to make a hard, smooth surface. We will show how much easier it is to pull the block on a smooth plank of wood by comparing the forces again.
We will also compare slopes of different angles, to see what difference that makes. In fact the slope had to be fairly shallow - around 7 degrees - or it would have been too hard to pull the blocks up the ramps.
2. Surveying
The tools used to build the pyramids were very basic by modern standards. Copper chisels were used to carve the stone, and because copper is quite soft the width of the cutting edge was only 8mm. Also the chisels wore out very quickly and had to be resharpened by a separate team of workers. To move the blocks the Egyptians used sledges and men pulling on ropes - they didn't have wheels at this time.
However, some of the tools are quite similar to modern versions. To check surfaces were vertical or horizontal, and to check right angles, they used the sorts of tools you see on the right (although these are not the 'real' thing - they are versions made to put into tombs for the afterlife). The set square is very similar to the modern type, and although we use spirit levels nowadays, plumb lines are still used by builders and decorators to check vertical edges.
From this activity children will learn both about the ancient Egyptian way of thinking and building, and about important mathematical concepts - the meaning of the terms horizontal, vertical, and right angle.
The Activity - checking verticals, horizontals, and right angles
Children will use replicas of these tools (see pictures). Three groups at a time will try surveying, taking it in turns (about 5 minutes long) to use the three different tools.
The groups will explore the classroom, looking for surfaces which are meant to be vertical, horizontal, or have right angles, such as walls, doors, tables, and windows. Using these tools they will check to see if the surfaces are well made. As an extension, more able children can try using the tools to draw horizontal and vertical lines or right angles. They can check them using a modern spirit level.
One of the most debated questions in pyramidology is what sorts of ramps were used to drag the blocks up the pyramids. How exactly did they approach the upper levels? Some of the theories can be seen in the picture to the right.
Many have said there was one very long and high ramp, leading up one side of the pyramid (as in the drawing above). There are problems with this idea however. The ramp would be enormous, using vast amounts of materials to build, and would constantly have to be added to as the pyramid got higher. The sides could not be too steep, or the ramp would collapse, as it was made of materials like stone chips, mudbrick, and clay. Therefore the base had to be quite wide. The top also had to be wide enough to let teams of men pull blocks upwards, and also allow them to come down with their empty sledges. Overall, then, building such a ramp would have been almost as big a project as building the pyramid.
Another problem is that the quarry for the Great Pyramid is only 320m from the south side of the pyramid, and there is a big drop off at the quarry - so the limit in length for the ramp is 320m. This does not allow for a long enough ramp to get up to the higher levels - in fact it only gets you to 60m. This is because the ramps could not be very steep - only about 7 degrees (or 1 in 8) - or the men simply could not have pulled the blocks.
The Activity - testing ramp theories
There are other theories, including ramps on different sides of the pyramid, ramps winding up in spirals, and even a ramp on the inside of the pyramid. To test some of these theories, children will use wooden pyramid models, plasticine and modelling tools to build ramps, and spirit levels, which are set to allow them to check the ramp is not too steep (see pictures below). They will try to use as little plasticine as possible, just as the Egyptians would want to use as little ramp material as possible, to save time. We will weigh the plasticine of their final model to check this.
Children will also be careful that the ramp they build is smooth enough for the blocks to be pulled up; that it's at the right angle all the way along (about 7.5 degrees, measured using the spirit level you see in the photo above right); and that it's not too steep on the sides (to avoid collapse of the ramp). Also a line is marked on the board (see photo right) to show the location of the quarry - in other words, the point the ramp cannot go past. Children will try to find out how high up the pyramid the single ramp could go. If done properly the answer should be 6 or 7 levels (as you can see in the photo).
Most groups will only have time to test the single long ramp theory. A more able group could test another theory such as the spiral ramp, to see how much plasticine that uses (answer - a lot!).
This activity not only gives children an understanding of the difficulties in building the pyramid ramps, including the need for a stable and useable structure, it helps them to learn about angles, and also gives them practice in clay modelling skills.
Another very important issue in pyramid building is what sort of blocks were used, and how did they fit together? In fact, at different times in Egyptian history different methods were used (see diagram right). In the Step pyramid, the very first pyramid of all, the blocks were fairly small and stacked on top in sections that leant against the body of the pyramid (number 1). The Giza pyramids were built in horizontal layers (2) with larger limestone blocks. Special casing stones were made for the faces of the pyramid, so they were smooth - not step-like as they are today. You can see one of these casing stones, with one face cut to a slope, in the photo below.
Later pyramids (3 and 4) used much smaller and rougher blocks in the centre, or even mud bricks. These pyramids tend to be in very bad shape, having collapsed or almost completely worn away. However they would have been much quicker to build.
As well as the cuboidal blocks and the casing stones, there had to be
'corner' stones with slopes on two sides, and also a mini pyramid shaped
capstone, for the top. This is know as a 'pyramidion'. In fact in the
Great Pyramid, further inside the blocks were not nice and even
cube-types but much rougher, filled in with rubble. as well as the
pyramid was built over an existing mound of rock, shaped in square
'shelves' to accommodate the blocks, which saved a lot of time in
building the lower layers.
The Activity - building pyramids with four kinds
of block
Children will build their own pyramids, stacking four types of wooden
block in a similar way to how the Egyptians built the Great Pyramid. The
four types are shown here:
They are edge, corner, cube (not really a cube, but close), and
capstone. With the help of photos children try to first make a simple
two or three layer pyramid, to get the idea of how the casing stones fit
with the squares. Depending on how much time they have left they can try
more ambitious pyramids, with four, five or even six levels.
In the course of this, children not only learn about stable pyramid
construction, they can also try to detect number series. There are
certain mathematical rules about how many of each type of block are
needed for each level. More able children pehaps can write the numbers
down, work out the rules, and predict how many of each block would be
needed for a larger pyramid (e.g. 10 levels).
The rules are as follows: for layer n of a pyramid (counting from the
top, and starting with layer 3, as layer 1 is just the capstone and
layer 2 is just 4 corners), you need:
4 corners (a constant - you always need 4 corners!)
4X (n-2) edges (a simple multiple of 4)
(n-2) squared cubes (square numbers).
For example, for layer 7 you need:
4 corners
4X (7-2) =20 edges (5 on each side)
(7-2) squared = 25 cubes.
More able children may be able to see that as the pyramid gets bigger,
the number of cubes you need grows much faster than the number of edges.
building a four layer pyramid
Building a Six-Layer Pyramid
The pictures below show the sequence for building a six
layer pyramid.
