People record numbers in lots of different ways. This method was used by the Inca people and many others who lived near the Andes Mountains of South America.
Have you ever wondered how cranes can lift such heavy things? Their pulleys really help lighten the load. In this activity, have a play with some pulleys. These simple machines can make heavy weights as light as a feather!
In this trick, you’ll wrap a shoelace around a pencil and a strip of cardboard. The string seems to pass straight through both, tearing the cardboard, but leaving the pencil untouched!
