Lesson 2

Discover

 

Before you can accurately estimate surface area, it is critical that you have a mental image of the more common area units in both the SI and imperial systems. To help you visualize the size of these units, complete the following activity.

 

Try This 1

 

You will need the following:

• one or two old newspapers
• tape
• scissors
• measuring tape
• ruler with both SI and imperial units

Step 1: Begin by taking pages from an old newspaper. Lay them out to form a square measuring 1 m on each side. Tape the pages together. The square is 1 m2 in area.

 

Are there any items around you, such as a window or a cupboard, that match the size of this area? Record at least three items in a chart like the one that follows.

 

Step 2: Using another piece of newspaper, measure and cut out a small square that measures 1 cm on each side. The square is 1 cm2 in area.

 

Are there any items around you that match the size of this area? Record at least three items in the chart.

 

Step 3: Repeat Steps 1 and 2 for squares measuring 1 yd2 (1 yd by 1 yd), 1 ft2 (1 ft by 1 ft), and 1 in2 (1 in by 1 in) in area.

 

Based on what you found, answer the following questions.

1. The term referent refers to the items you found that were about the same size as the newspaper squares you created. A referent is the mental image you “see” or “refer to” when you work with the various area units such as 1 m2 or 1 ft2.
   
   Fill in the chart with the referents that you found in Steps 1, 2, and 3.
   
   

   Area Unit	Referent 1	Referent 2	Referent 3
   1 m2
   1 cm2
   1 yd2
   1 ft2
   1 in2

   
   
2. A skill that is useful with respect to the trades is being able to convert between area units. Using the squares that you created from newspaper, determine the conversion factor between the following units.
   
   
   1. 1 m2 = ______ cm2
   2. 1 yd2 = ______ ft2
   3. 1 ft2 = ______ in2
   4. 1 yd2 = ______ in2
   5. 1 m2 = ______ ft2
   6. 1 m2 = ______ yd2

Save your work in your course folder.

 

Share 1

 

Share your responses to the questions in Try This 1 with a classmate or in a group.

• Share your lists of referents to create a larger, combined list.
  
  
• Confirm your conversion factors with your partner or your group and by using the Internet.

If required, save a copy of your discussion in your course folder.