Using Pulleys and Gears by Wendy Sadler
Simple Machines for Kids: Science and Engineering for Children - FreeSchool
7 Facts About Pulleys
Last updated: July 17, Y ou've probably seen those amazing TV strongmen who can pull cars with their hair and drag trains with their teeth. But did you know science can make you strong too? If you need to lift huge weights, don't strain your back: use the power of science—and an amazing device called a pulley. Let's take a closer look at how they work! Photo: A pulley mounted on a huge lifting frame to make it safer to use. Thanks to the power of pulleys, one person can lift far more than their own weight without straining any muscles, because several ropes or chains support the extra weight.
A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that does not transfer power to a shaft, but is used to guide the cable or exert a force, the supporting shell is called a block, and the pulley may be called a sheave. A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope , cable , belt , or chain. Pulleys are also assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another. A set of pulleys assembled so that they rotate independently on the same axle form a block.
We don't know who invented the first wheel, but we do know that it was one of our most important inventions.
this boys life chapter summary
Once upon a time a person needed to move something heavy. He or she picked up a long stick and stuck it under the edge of the heavy object and then pushed down on the other end of the stick. And the first simple machine was invented. Simple machines are just that. The simplest form of using one thing to accomplish something faster or better. A tool. They were the first ones created and we still use them today.
They allow us to move and transport heavy workloads with minimum effort. But, how much do you know about them? The origin of pulleys is uncertain. Historians believe that people from Mesopotamia used them to hoist water in BF. Archimedes of Syracuse, an Ancient Greek physicist who invented the principle of the lever and the screw pump, is also credited for the invention of compound pulleys.