# Biscuit factory: three gears: assessment

TLF ID L9782

Test your understanding of ratios by interpreting three-wheel gear systems where the wheels have different numbers of teeth. For example, how many rotations does a 10-tooth gear wheel make when driven by two driver wheels having 20 and 10 teeth? Also, choose a combination of three gear wheels to achieve a required number of rotations of a specified wheel. This assessment object is one in a series of two objects.

#### Educational details

Key learning objectives
• Students interpret situations involving sense of rotation and using clockwise and anticlockwise conventions.
• Students demonstrate multiplicative thinking strategies to interpret situations and solve problems involving ratios.
Educational value
• Tests student understanding and interpretation of multiplicative thinking and ratios as applied to a practical situation.
• Assesses student's thinking in relation to solving ratio problems in a gear system.
• Includes a printable report of the student’s performance for teacher–student discussion.
Year level

7; 8; 9

TopicsRatios
Learning area
• mathematics
Strand
• Mathematics/Number
• Mathematics/Working mathematically
• Mathematics/Measurement
Student activity
• Interactives;
• Experiment;
• Analysis;
• Modelling

#### Other details

Contributors
• Technical implementer
• Script writer
• Name: Rod Rees
• Organisation: Rees Films Pty Ltd
• Address: Blackburn VIC 3130 Australia
• Subject matter expert
• Name: Howard Reeves
• Address: Lindisfarne TAS 7015 Australia
• Educational validator
• Name: Gayl O'Connor
• Organisation: Education Services Australia
• Address: Melbourne VIC 3000 Australia
• URL: http://www.esa.edu.au/
• Publisher
• Date of contribution: 20 Sep 2013
• Organisation: Education Services Australia
• Address: Melbourne VIC 3000 Australia
• URL: http://www.esa.edu.au/
• Script writer
• Name: Howard Reeves
• Address: Lindisfarne TAS 7015 Australia
Access profile
• Colour independence
• Device independence
• Hearing independence
• Generic
Learning resource type
• Assessment resource
Browsers
• Microsoft Internet Explorer - minimum version: 8.0 (MS-Windows) - maximum version: 9.0 (MS-Windows)
• Firefox - minimum version: (MS-Windows)
• Safari - minimum version: 5.1 (MacOS)
Operating systems
• MacOS - minimum version: 10.6
• MS-Windows - minimum version: XP - maximum version: 7
Rights
• © Education Services Australia Ltd, 2013, except where indicated under Acknowledgements.

## Related items

Others in the series: