The stretch of a rubber band

The stretch of a rubber band

Pencil and paper
Overview
Connecting to the Curriculum
Marking Student Responses

A tray is hanging by a thick rubber band. When John adds blocks to the tray, the rubber band stretches and the tray moves closer to the desk top. His results are shown on the chart below.

Number of blocks Height of tray above desk top (cm)
0 60
1 50
2 40
3 30
a) Graph John's results below. You must label and number each axis.
 

TITLE: The Amount of Stretch in a Rubber Band
b) What can you say about the relationship between the number of blocks and the stretch of the rubber band?

 
 
 
 
 
c)
How many blocks will be needed to make the tray just touch the desk top?
  (A)  4          (B)  5          (C)  6          (D)  7          (E)  8
Level:
4
Curriculum info: 
Science, Communicating in science, Physical World
Keywords: 
physics concepts, stretch, graph construction, graph interpretation
Description of task: 
Task: Use data in a table to construct a graph and answer questions about the patterns. Assessment focus: interpreting tables and graphs.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Interpret representations
This resource provides opportunities to discuss the relative benefits of using tables or graphs to convey the same set of data.
 
Science capabilities: 
Interpret representations
Answers/responses: 
    Y8 (08/98)

a)
  • All 4 points plotted accurately (bar or line graph).
  • Axis labelled accurately.
  • Axis numbered accurately.
  • Unit specified (cm).

moderate
moderate
moderate
difficult
b) For any statement such as:
For every block added the rubber band stretches 10 cm. (There is a linear relationship between the number of blocks and the stretch of the rubber band).		 difficult
c) C easy