# Balance the blobs: find the rule 1

TLF ID L5979

Balance scales by using blobs. Using unit ratios, such as 1:3, 2: 1 or 1:4, explore how many black blobs and white blobs balance each other. Discover the rule that balances the scales with the correct number and type of blobs. For example, 2 black blobs balance 1 white blob. Find out how many black blobs balance 2 white blobs. Build a number pattern. Then use the rule to solve a problem by moving blobs to make the scales balance. This learning object is the first in a series of three learning objects.

#### Educational details

Key learning objectives
• Students identify that one item can be used to represent a value of more than one.
• Students predict the numerical relationship (ratio) between two or three types of items.
• Students analyse number sentences and record the equivalent relations.
Educational value
• Introduces the concept of ratio pictorially with unit ratios such as 1:3.
• Provides experience in basic algebraic thinking by moving from one-to-one correspondence thinking to one-to-many thinking.
• Features a dynamic model of equality that allows the students to explore number relations through the equal-arm balance (scales).
• Includes a printable worksheet for students with a record of the rule and its solution, and a new problem to solve using the same rule.
Year level

4

Learning area
• mathematics
Strand
• Mathematics/Number and algebra
Concept
• Mathematics/Algebra
• Mathematics/Algebraic methods
• Mathematics/Arithmetic
• Mathematics/Equations
• Mathematics/Number concepts
• Mathematics/Number operations
• Mathematics/Number patterns
• Mathematics/Number relationships
• Mathematics/Number sentences
• Mathematics/Numbers
• Mathematics/Thinking
• Mathematics/Simple equations
• Mathematics/Reasoning
• Mathematics/Working mathematically
Skill
• Knowledge;
• Comprehension;
• Application;
• Analysis
Student activity
• Interactives;
• Experiment;
• Analysis;
• Modelling
Learning design
• Experiential learning;
• Independent learning;
• Problem solving;
• Visual learning

#### Other details

Contributors
• Publisher
• Date of contribution: 20 Sep 2013
• Organisation: Education Services Australia
• Address: Melbourne VIC 3000 Australia
• URL: http://www.esa.edu.au/
• Subject matter expert
• Name: Dr Jenni Way
• Organisation: University of Western Sydney
• Address: Penrith NSW 2750 Australia
• Script writer
• Address: Ultimo NSW 2007 Australia
• Technical implementer
• Educational validator
• Name: Graham Jones
• Organisation: Griffith University
Access profile
• Colour independence
• Device independence
• Generic
Learning resource type
• Interactive 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.

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