E2.9 Use square centimetres (cm2) and square metres (m2) to estimate, measure, and compare the area of various two-dimensional shapes, including those with curved sides.
Activity 1: Visualizing the Standard Units of Area
Goal
In this activity, students construct two-dimensional shapes with a given area.
Materials
- Several very large cardboard boxes (for stove or refrigerator)
- Large newspaper
- Scissors
- Metres
- Adhesive tape or sticker
Instructions
On a large piece of cardboard, draw and cut out a square with sides one metre long.
Post this card on the classroom wall as a one-square-metre benchmark.
Ask students to construct a square with an area of 1 cm2 using a piece of cardboard and compare it to the 1m2 benchmark. They refer to the reference size on the wall to check whether their construction respects the requested measurement. Ask some students to tape their construction to a wall for comparison and discussion.
Using pages of large newsprint, have students construct a rectangle with an area of 1 m2 using their cm2 pieces. Have some teams show their construction to the rest of the class.
Source: adapted and translated from L'@telier - Ressources pédagogiques en ligne (atelier.on.ca), p. 1-2.
Activity 2: The Appropriate Area Unit
Goal
In this activity, students choose the most appropriate standard unit to estimate and determine the area of familiar objects.
Materials
- 30 cm ruler (graduated in centimetres and millimetres)
- Metre sticks
- A one-square-metre cardboard displayed on the wall
- The grid in 1 cm2 squares photocopied on an overhead
Instructions
For each object listed in the table below:
- Choose the most appropriate unit to determine the area of the object.
- Estimate the area of the object.
- Use the manipulatives to determine the approximate area of the object.
- Review the units chosen for each object and the approximate areas found.
|
Most Appropriate Unit of Area |
Estimation |
The Approximate Area |
|
|
The top of a desk |
|||
|
A slice of bread |
cm2 |
100 cm2 |
120 cm2 |
|
The floor of a corridor |
|||
|
A wall in the gym |
|||
|
A bank card |
|||
|
A basketball court |
|||
|
A sticky note |
|||
|
A soccer field |
Source: transalated from L'@telier - Ressources pédagogiques en ligne (atelier.on.ca), p. 3.