ED3662 Lecture Notes - Lecture 2: Weighing Scale, Metric System, Kilogram
Week Two
Lecture Two: Mass
Big Ideas about Measurement
- Identify the attribute to be measured
o Length
o Mass
o Capacity
o Area
o Volume
o Time
- Compare and order
- Use non-standard units
- Use Standard units
- Application of measurement
o If it is a measurement lesson, you should be measuring
What is Mass (Siemon et. Al)
- Mass
o The quantity of matter an object contains
o Metric Units – grams/kilograms
o An object has mass (say 100kg)
▪ This makes it heavy enough to weigh 100kg
▪ An object’s weight is how hard gravity is pulling on it
▪ Because gravity is pretty much the same anywhere on earth, we don’t notice a
difference
▪ An objects mass doesn’t change (unless you remove some), but it’s weight can
change
- Weight
o Size of the force gravity exerts on an object
o Determined by how much mass it has
o Measured in Newtons
Curriculum
- Mass is introduced to students in year 2
- We start developing the understandings from Pre-Primary
- Try to develop in the students a belief that in dealing with mass, you cant trust what you see
o Eg different sized balls
Hefting
- Development of language
o heaviest / lightest – polarised/dichotomy
o investigating the use of comparative language
o eventually we have to start using superlatives (light, lighter, lightest etc) so that the
differentiation can be more fine grained the purpose of measurement all measurement
is about the comparison of different attributeslanguage helps us articulate the
comparison
- The purpose of measurement
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o All measurement is about the comparison of different attributes
o Language helps us articulate the comparison
- Comparisons
o Direct comparison using hands
o Indirect comparison using hands
o Direct comparison using a balance scale
o Indirect comparison using a balance scale
o Indirect measurement using balance scales using non-standard units (Blocks - quantifying)
o Indirect measurement using balance scales using standard units (Weights)
Scales
- Needs to be used appropriately in appropriate age ranges
- Variety of scales
Standard units for mass
- Metric system – grams
- In the metric system the basic unit of weight is directly related to units used for volume and length
- The inventors of the metric system began with a litre of water (one cubic decimeter) and decreed
that the weight of that amount would be one thousand grams, or one kilogram
- Once again, the 10-to1 relationship and the use of powers of 10 are built in to the system by
design
Converting Standard Units
Questioning
- Consider the following questions
o Which is heaviest
o How heavy is it
o How much heavier is it than the other one?
Developing a ‘sense’ of mass and of standard units
- Find a kilo of:
o Potatoes, junk mail, cotton balls, bottle tops, straws, lead fishing weights, socks
o Objects have the same mass but differing objects
- Helps to develop the understanding that objects with the same mass don’t have the same volume
First Steps in Maths
- To measure something means to say how much of a particular attribute is has
- We measure by choosing a unit and working out how many of the unit and working out how many
of the unit it takes to match the thing
- When we want to describe ‘how big’ or ‘how much bigger’ we use numbers
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Identify the attribute to be measured: length, mass, capacity, area, volume, time. If it is a measurement lesson, you should be measuring. Mass: the quantity of matter an object contains, metric units grams/kilograms, an object has mass (say 100kg) Weight change: size of the force gravity exerts on an object, determined by how much mass it has, measured in newtons. Mass is introduced to students in year 2. We start developing the understandings from pre-primary. Try to develop in the students a belief that in dealing with mass, you cant trust what you see: eg different sized balls. The purpose of measurement: all measurement is about the comparison of different attributes, language helps us articulate the comparison. Indirect comparison using hands: direct comparison using hands, direct comparison using a balance scale. Indirect measurement using balance scales using non-standard units (blocks - quantifying) Indirect measurement using balance scales using standard units (weights) Needs to be used appropriately in appropriate age ranges.
