Julian's Science Fair
Projects by Grade Level
1st 2nd 3rd 4th 5th 6th
7th 8th 9th 10th 11th 12th
Home Primary School Elementary School Middle School High School Easy Projects Advanced Award Winning Popular Ideas
   

Engineering science fair project:
Find out how elevators work using pulleys




Science Fair Project Information
Title: Find out how elevators work using pulleys
Subject: Engineering
Grade level: Elementary School - Grades 4-6
Academic Level: Ordinary
Project Type: Experimental
Cost: Low
Awards: 2nd place, Canada Wide Virtual Science Fair (2006)
Affiliation: Canada Wide Virtual Science Fair (VSF)
Year: 2006
Description: See Picture
Link: http://www.virtualsciencefair.org/2006/must6a2/
Short Background

A pulley is something that is used to lift objects with heavy weights. It is a kind of simple machine. It is sometimes called a block and tackle. Pulleys are usually used in sets designed to make the amount of force needed to lift something smaller.

Types of pulleys:

  • Fixed A fixed or class 1 pulley has an axle that is "fixed" or anchored in place. A fixed pulley is used to redirect the force in a rope (called a belt when it goes in a full circle). A fixed pulley has a mechanical advantage of 1.
  • Movable A movable or class 2 pulley has an axle that is "free" to move in space. A movable pulley is used to transform forces. A movable pulley has a mechanical advantage of 2. That is, if one end of the rope is anchored, pulling on the other end of the rope will apply a doubled force to the object attached to the pulley.
  • Compound A compound pulley is a combination fixed and movable pulley system.
    • Block and tackle - A block and tackle is a compound pulley where several pulleys are mounted on each axle, further increasing the mechanical advantage. Plutarch reported that Archimedes moved an entire warship, laden with men, using compound pulleys and his own strength.

Diagram of a fixed pulley (brown) that can raise or lower a weight (dark gray) using a rope (light gray)    Movable pulley

Lifts began as simple rope or chain hoists. A lift is essentially a platform that is either pulled or pushed up by a mechanical means. A modern day lift consists of a cab (also called a "cage" or "car") mounted on a platform within an enclosed space called a shaft, or in Commonwealth countries called a "hoistway". In the past, lift drive mechanisms were powered by steam and water hydraulic pistons. In a "traction" lift, cars are pulled up by means of rolling steel ropes over a deeply grooved pulley, commonly called a sheave in the industry. The weight of the car is balanced with a counterweight. Sometimes two lifts always move synchronously in opposite directions, and they are each other's counterweight.

In the middle 1800's, there were many types of crude elevators that carried freight. Most of them ran hydraulically. The first hydraulic elevators used a plunger below the car to raise or lower the elevator. A pump applied water pressure to a plunger, or steel column, inside a vertical cylinder. Increasing the pressure allowed the elevator to descend. The elevator also used a system of counter-balancing so that the plunger did not have to lift the entire weight of the elevator and its load. The plunger, however, was not practical for tall buildings, because it required a pit as deep below the building as the building was tall. Later a rope-geared elevator with multiple pulleys was developed.

Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License)

For More Information and Pictures: Pulleys

Useful Links
Science Fair Projects Resources
Citation Guides, Style Manuals, Reference
General Safety Resources
Electrical Safety FAQ
Engineering Science Fair Project Books


              




Follow Us On:
       

Privacy Policy - About Us

Comments and inquiries could be addressed to:
webmaster@julianTrubin.com


Last updated: June 2013
Copyright 2003-2013 Julian Rubin