The focus of this activity is to find out what students know and understand about length and the metric system. Are students able to identify the standard unit for length (metres) and the relationship between metres and other measures, e.g. mm, cm and km? Do students understand the ten times bigger/smaller concept or do students simple apply a rule such as “move the decimal point” without truly understanding what this means?

##### Purpose
• Develop a clear definition of length and provide examples of when it is used
• Recognise that the standard unit for length is the metre
• Explain the relationship between metres, centimetres, millimetres and kilometres
• Recognise and explain the connection between place value (including decimals) and the metric system
• Convert between mm, cm, metres and km and explain the strategy used
• Accurately use measuring tools, such as rulers and tape measures to find the length of various objects
• Make comparisons between different measures and explain their relationship

##### Stage 3.2 – Length 2
• Connect decimal representations to the metric system (ACMMG135)
• Convert between common metric units of length (ACMMG136)

##### At the end of this lesson students should be able to answer the following questions
• What is the metric system? How is the metric system related to place value?
• What is length? What is a definition for length? How do we measure length?
• What are different tools we use to measure? How do we use these tools accurately?
• What is the standard unit for length? What are the related units?
• What is the relationship between the units, e.g. 1 cm and 1 mm?
• How can we convert between the units in order to compare size?
• Can ratios help us to better understand the relationships between the measures?
• How can we use ratios to help us convert between measures?