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Mind Your Pints and Quarts: Making Sense of Liquid Measurement

Lesson Question:

How can students use the Visual Thesaurus to learn the U.S. customary system of measuring liquids and to apply their knowledge in solving measurement conversion math problems?

Applicable Grades:


Lesson Overview:

In this lesson, students use the Visual Thesaurus to learn about the different units of measuring liquids in the US customary system and how they relate to one another. They then develop mathematical strategies for solving conversation problems involving different units within this system.

Length of Lesson:

One hour to one hour and a half

Instructional Objectives:

Students will:

  • analyze liquid measurement conversion problems
  • use the Visual Thesaurus to learn how the different units of US liquid measurement relate to one another
  • use the Visual Thesaurus and their knowledge of conversion strategies to solve liquid measurement conversion problems


  • student notebooks
  • white board
  • computers with Internet access
  • different containers and measuring devices (e.g., measuring cup, quart container for milk, etc. — to help students conceptualize the different liquid units)



Analyzing a liquid measurement problem:

  • Write the following problem on the board: A standard barrel of oil measures 42 US gallons. If you were given only a one-cup measuring cup with which to measure a barrel of oil, how many cups would it take to fill the barrel?
  • Ask students to join partners and discuss the warm-up problem without trying to find its answer. Instead, have partners decide what information they would need in order to solve the problem.
  • Elicit students' responses, and establish that one would need to know how many cups are in a gallon in order to solve the problem.


Introducing the US Customary System of measurement:

  • Explain to the class that in order to solve the problem in the warm up, students will need to first figure out how all the different units relate to one another in the US system for measuring liquids. Then, they will be able to return to the problem having learned how many cups are in one gallon.
  • Display the Visual Thesaurus word map for gallon and point out the definition¬† "United States liquid unit equal to four quarts?" and explain that the United States Customary System for measurement is different than the system nearly all other countries in the world use — the metric system.
  • Look up the term United States liquid unit in the VT and reveal the different types of US liquid units contained in the Visual Thesaurus database by clicking on the red meaning bubble attached to the term or by clicking on the definition of United States liquid unit listed in the meaning list on the right side of the word map display. [The word map will configure to show the meaning "a liquid unit officially adopted in the United States Customary System" as the center of the map, with ten other red meaning bubbles fanning out above the central meaning, attached to words like pint, quart, gallon, etc.]

Converting from one liquid unit of measurement to another:

  • Have students copy and complete the following chart in their notebooks by using the Visual Thesaurus interactive display of United States liquid units and their definitions.

US liquid unit

converting to another unit of measurement

fluid ounce

1 fluid ounce = ____cup (hint: this answer should be a fraction)


1 cup = ____ounces


1 pint = ____cups or ____ounces


1 quart = ____pints or ____cups


1 gallon = ____quarts or ____pints

  • Explain to students that it will often require multiplication to complete the chart; if they are converting from a larger unit of measurement to a smaller one, they will need to multiply [e.g., to convert one pint into ounces, students will need to multiply 2 (cups in a pint) by 8 (ounces in one cup) to find that one pint is equal to 16 ounces.]
  • Circulate around the room as students work, ensuring that students are clicking on each of the liquid units of measurement in order to see how each of the units is defined. (Students may also need to be reminded that clicking on the "BACK" button in the upper left hand corner of the tool bar will return them to the previous display.)

Determining how many cups equal a gallon:

  • After students have completed the conversion chart, have them share their answers and explain what math problems they had to solve in order to complete the chart.
  • Model in a think-aloud fashion the process of determining the number of cups that are equal to a gallon (e.g., "We now know that there are four quarts in a gallon and there are four cups in a quart; therefore, I need to multiply 4 x 4 to determine that there are 16 cups in a gallon.").
  • A great visual way to reinforce this lesson on conversion would be to have students draw the following image in their notebooks [which conveys the relative size of a gallon (the large G) to the smaller units of measurement which descend in size (i.e., quarts — Q; pints — P; and cups — C)].


Returning to the warm-up problem:

  • As a review of the conversion strategies demonstrated in class, ask students to return to the original warm-up problem.
  • Invite a student to the front of the classroom to explain his or her conversion strategy [i.e., 42 (number of gallons in a barrel of oil) X 16 (number of cups in a gallon) = 672 cups of oil].

Extending the Lesson:

  • To further challenge students, you could give them additional conversion problems requiring division (e.g., "I have 64 fl. oz. of milk. How many quarts do I have?"). Or, you could also introduce conversion problems involving converting measurements in the metric system to the US customary system¬† (e.g., "I have 20 liters of soda. How many one-cup servings can I pour from those 20 liters?")


  • Check whether or not students accurately completely the liquid units conversion chart in their notebooks.
  • Assess students' comprehension of the various liquid units of measurement and their relationships by seeing if they can accurately compute conversions between smaller and larger units within the US customary system for measuring liquids.

Educational Standards:


Standard 4. Understands and applies basic and advanced properties of the concepts of measurement

Level II (Grades 3-5)

1. Understands the basic measures perimeter, area, volume, capacity, mass, angle, and circumference
2. Selects and uses appropriate tools for given measurement situations (e.g., rulers for length, measuring cups for capacity, protractors for angle)
3. Knows approximate size of basic standard units (e.g., centimeters, feet, grams) and relationships between them (e.g., between inches and feet)

Level III (Grades 6-8)

4. Solves problems involving units of measurement and converts answers to a larger or smaller unit within the same system (i.e., standard or metric)
5. Understands the concepts of precision and significant digits as they relate to measurement (e.g., how units indicate precision)
6. Selects and uses appropriate units and tools, depending on degree of accuracy required, to find measurements for real-world problems
7. Understands formulas for finding measures (e.g., area, volume, surface area)

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Comments from our users:

Friday October 2nd 2009, 3:39 AM
Comment by: Noel B.
So - will the students enquire why such a strange system is still in use?
I remember all those tables I learned in primary school (over 50 years ago!!) - & I'm so glad I don't need them anymore! Australians are still clutching some of the old measures - but they don't have a clue how to relate them to their "parts". Takes a while to teach everyone - & to see how a simple set of metric measures makes good sense - well the USA doesn't use pounds, shillings & pence, does it!

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