Topic C: The Metric System
When you measure something, you are comparing. Measurement is comparing something with a standard unit of measure.
In the past, units of measure were based on things found in a community. Often, lengths of parts of the body were used to measure:
- Inch: the width of a thumb
- Span: the distance from tip of thumb to tip of little finger when the hand is spread out
- Foot: the distance from big toe to heel of foot
- Yard (becomes “rod): the distance from tip of nose to tip of thumb of an outstretched hand and arm
- Cubit: the distance from the tip of the middle finger to the elbow
- Fathom: the distance from the tip of one hand to the tip of the other with both arms stretched out
- Mile: 1000 military double steps in the Roman army (mile passuum means “1000 paces”)
The problem with these units was the distances would be different based on the size of the person doing the measuring. The problem grew even more when trade was started between cities.
Over a long period of time, people in different countries came up with different standard units of measure.
The British came up with imperial units such as inch, foot, yard and mile.
The French came up with metric units such as metre, centimetre, litre and gram. In Canada, we use both metric and imperial units.
Measuring Length
The basic unit of measure for length is the metre (abbreviation m). If you stretch your arm straight out beside you, a metre is about the distance from the tip of your nose to the tip of your middle finger.
Exercise 1
Consider the following distances. Answer yes or no if you would use a metre to measure. Check your work using the answer key at the end of the exercise.
Example:
- The length of a table – Yes
- The width of your watchband – No
- length of your classroom
- thickness of a piece of paper
- length of your pen or pencil
- height of the door
- distance from Prince George to Fort Nelson
- the width of your baby finger
- the size of a postage stamp
- the thickness of a quarter
- the length of the hallway outside your classroom
- the distance from your home to college
- the height of your coffee mug
- the width of your book
- the distance from your home to Moncton, New Brunswick
- the length of a city bus
- yes
- no
- no
- yes
- no
- no
- no
- no
- yes
- no
- no
- no
- no
- yes
Exercise 2
Estimate the length of each item. Remember a metre is about the distance from the tip of your nose to the tip of your middle finger when your arm is stretched out beside you. Be sure to include the unit of measure in your answer. Have your instructor check your work.
- the height of the doorway
- the height of your table
- the width of the doorway
- the length of your arm
- the distance from the floor to hip
- the distance from the floor to waist
- the height of the ceiling
- the width of the window
- the length of your classroom
- the width of your classroom
Exercise 3
Circle the most reasonable measure. Remember a metre is about the distance from the tip of your no