# Capacity: Cups, Pints, Quarts and Gallons

by on May 24, 2011

The math concept of capacity can be a tricky one for children, as it requires them to think about the amount of space inside a 3-dimensional object, which is less concrete than other concepts.  Further to that, your child will learn that we tend to use the word capacity when we refer to liquids (as opposed to solids, when we tend to use the word volume).  There are several things around your house (think kitchen!) that will help you and your child play with the capacity of containers.

What is it?

Capacity is the maximum amount that something can contain or hold.  Your child will likely learn about the U.S. Customary system first, and move on to the Metric system later.  We are going to talk about the U.S. Customary system today.

• Capacity can be measured in fluid ounces, cups, pints, quarts, and gallons
• There are 8 fluid ounces in a cup, 2 cups in a pint, 2 pints in a quart, and 4 quarts in a gallon
• Your child may not be exposed to fluid ounces at the beginning of learning about capacity

Tips/Activities

KITCHEN TOOLS

• Have fun exploring various measuring tools in your kitchen.  Ask your child to see if she can find anything in the kitchen that is used for measuring.  Place all the items on the counter.  Next, ask her to put them into 3 groups: 1 group that measures how heavy something is, one group to measure how much liquid there is, and another group that measures how much of something solid there is.  Hopefully, she will pull out tools such as measuring cups, a kitchen scale, measuring spoons, etc..
• Ask her to put away all the tools except the ones used for measuring liquids
• Talk about why we would need such tools when we cook and bake (to ensure the quantities are consistent)

FRIDGE FINDS

• The refrigerator is a great place to find various vessels for capacity.  If you have a large plastic jug of milk, take that out of the fridge and tell your child that it holds a gallon of milk.  That is its capacity.  That is the maximum amount of liquid it can hold.  If you have a smaller milk container, look at the label to check its capacity.  It might be a quart.
• Look for other containers in your fridge.  You may have a 2 quart container (such as a buttermilk container), or you might have a whipping cream container that measures a pint.  Show all these containers to your child so she can begin to have some visual clues as to how big each of these units really are.

POUR THE LIQUID

Materials: 1 cup measuring cup, empty pint container (whipping cream), empty quart container (ice-cream), empty gallon container (milk, orange juice)

• Ask your child to estimate how many 1 cup measuring cups of water she thinks will fit into each of the other containers.  Have her think of her estimates as she’s looking at the containers.  Then, have her fill them with water and experiment by pouring the water into each of the other containers.  If you’d like to keep track of your estimates and measures, you can simply use the following:

I think I can put _______ cups in a pint.       Real answer:_____________

I think I can put _______ cups in a quart.     Real answer:____________

I think I can put _______ cups in a gallon.    Real answer:____________

I think I can put _______pints in a quart.      Real answer:____________

I think I can put _______pints in a gallon.     Real answer:____________

I think I can put _______ quarts in a gallon.   Real answer:___________

What to Watch For

• The purpose of these activities is to familiarize your child with the various names we use in measuring the capacity of liquids.  Be sure she is using the vocabulary as she explores the containers.  For example, you will want to hear her say things such as, “I can put the same amount of water in 2 pints as I can put in 1 quart.  They have the same capacity!”
• If your child has learned about liters or milliliters at school, you can tell her that these are also units to measure capacity, but that they are part of the metric system, which is a whole other way to measure.  Tell her that she will learn about those another day.

WANT MORE?

• As always, playing math games at home is a great way to reinforce math skills learned in school.