No one knows when early engineers first tackled this challenge Sometime after the wheel was invented they discovered the pulley This well uses a type of pulley fixed
A pulley is a simple machine that uses a long pulling rope with a load attached on one end The other end is threaded along a grooved wheel The wheel changes the direction of the pull Moveable pulley Fixed pulley System of two pulleys
ANCIENT ELEVATORS How did ancient Egyptians lift heavy stone to build pyramids some 4 600 years ago They had no iron to make a strong pulley axle Researchers think ancient Egyptians used a polished stone cylinder with a groove carved for a rope The cylinder could turn smoothly in a stone cradle as workers pulled the rope Math at Work The Greek scholar Archimedes developed an elevator around 236 BCE It used a screw to lift water crops for
Each block in the Great Pyramid of Giza in Egypt weighs about 5,000 pounds 2,268 kilograms 9
