Lesson 11 — Activity 3: Measuring Capacity


Getting Ready


The last unit of imperial measurement you will look at is capacity. Remember from the lesson on metric measurements that capacity is the amount a container can hold.

Here are the imperial measurements of capacity:


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As you noted in the image above, the five units of measurement that we use the most when talking about capacity are fluid ounces, cups, pints, quarts, and gallons.


  • A fluid ounce is very small. Remember the term ounce when you were measuring mass? Don't get these two units confused. An ounce measures weight, whereas a fluid ounce measures capacity. Fluid ounce can be abbreviated as fl oz.
  • Medicine can be measured in fluid ounces.

                      

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  • A cup holds about 8 fluid ounces. The abbreviation for cup is c.

  • It is a measure often used in cooking.

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  • 3 cups all-purpose flour, spooned and levelled
  • 1 teaspoon baking soda
  • 2 teaspoons cream of tartar
  • 1/2 teaspoon salt
  • 1 cup of unsalted butter
  • 1/2 cup of brown sugar
  • 1 1/4 cups of granulated sugar
  • 2 large eggs
  • 2 teaspoons vanilla extract
  • 2 teaspoons ground cinnamon

You can see there are many uses of cups in this recipe.


  • A pint is equal to 2 cups (e.g., a large glass of milk). The abbreviation for pint is pt.
  • One pint is equal to 2 cups, which is equal to 16 fluid ounces.
  • Often pubs will sell beer in pints.

          

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  • A quart is the same as 4 cups or 2 pints. The abbreviation for quart is qt.
  • 1 quart = 2 pints = 4 cups = 32 fluid ounces
    Milk comes in a quart in the US.

               
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If we still need to measure larger amounts, we can switch to using gallons.

  • A gallon is the same as 16 cups, 8 pints, or 4 quarts. It is the largest liquid measurement. A gallon is abbreviated gal.
  • 1 gallon = 16 cups = 8 pints = 4 quarts

There are two different types of gallons in North America.
  • A US Gallon is 3.785 litres. If you think of a 4 l container of milk, a US gallon would be slightly smaller than the milk container.
  • A Canadian gallon is 4.54 litres. It is bigger than a US gallon. It would be slightly bigger than a 4 l container of milk.

                 

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When working with imperial measurements at school, at work, at home, or in your community, it is important that you choose the appropriate unit of measure. Practise choosing the appropriate unit of measure for the items below.


If you wanted to measure how much paint you would need to paint your house, you would choose:
  • fluid ounces
  • cups
  • pints
  • quarts
  • gallons


The most appropriate unit would be gallons.



Courtesy of iStock


Courtesy of Pixabay

If you wanted to measure how much flour you require in a recipe, you would choose:
  • fluid ounces
  • cups
  • pints
  • quarts
  • gallons


The most appropriate unit would be cups.



If you wanted to measure how much cough medicine you should take, you would choose:
  • fluid ounces
  • cups
  • pints
  • quarts
  • gallons


The most appropriate unit would be fluid ounces.




Courtesy of Getty

  Self-check!

Try This!

Now that you have looked at imperial measurements, click here to try this game to compare units of length, mass, and capacity.