The Elephant on the Bridge

She's standing still but there are still forces on her - find out what they are.

Lesson idea. A fun scenario to introduce the idea of balanced forces. Could be used to frame the set of related ORBIT activities if the scenario was that Nelly the Elephant had escaped from the circus and consequently found herself in a number of different situations (crossing a bridge, crossing a river on a raft, jumping from a high cliff with a parachute, finding a new home with an unsuitable floor, etc) and needing help from the children. A sense of the ridiculous often appeals.

Teaching approach. An interactive way of exploring this activity might be to have the children in small groups^(ta) building a rope/string bridge and using a model elephant to stand on it. The children could either observe what happens and then discuss it or could film it and watch in time lapse to see exactly where the movement occurs in the bridge/elephant system. The latter would assist them in considering the direction of the forces acting as they would be able to see the direction of movements very clearly.

Resource details
Title	The Elephant on the Bridge
Topic
Teaching approach
Learning Objectives	to gain understanding of the nature of force and the way in which force acts on objects, in the context of an elephant balanced on a bridge to make observations and discuss the direction simple forces
Format / structure
Subject
Age of students / grade
Table of contents
Additional Resources/material needed	http://www.pbs.org/wgbh/buildingbig/lab/shapes.html
Useful information
Related ORBIT Wiki Resources	What floats and what sinks? What makes a good paper airplane? Building bridges from a piece of A4 paper Which material makes a good parachute? Forces in Static Situations Floors and Pillars
Other (e.g. time frame)
Files and resources to view and download	Download the document here File:The Elephant on the Bridge.doc, or view it on the wiki Elephant on the Bridge/Lesson Document
Acknowledgement	This resource was adapted from resources and original ideas contributed by Paul Warwick, at the Faculty of Education, University of Cambridge.
License