Beacon Lesson Plan Library

Thirsty for A Liter or Milliliter?

Cindy Jacobs


This lesson allows students to select and estimate the most reasonable metric units of measurement to determine capacity using liters or milliliters.


The student uses and justifies different estimation strategies in a real-world problem situation and determines the reasonableness of results of calculations in a given problem situation.

The student uses concrete and graphic models to develop procedures for solving problems related to measurement including length, weight, time, temperature, perimeter, area, volume, and angles.

The student uses direct (measured) and indirect (not measured) measures to calculate and compare measurable characteristics.

The student uses estimation strategies to determine a reasonable estimate of a quantity.

The student solves real-world problems involving measurement using concrete and pictorial models for the following: length (for example, half-inch, centimeter); weight (for example, pound, kilogram); time (fifteen-, five-, and on-minute intervals); capacity (for example, cup, liter); temperature (Fahrenheit and Celsius); angles (right).

The student uses customary and metric units to compare length, weight, and capacity.


-Appropriate container for liter and milliliter (eyedropper works well for milliliter)
-Quart container (milk carton)
-Index cards (two for each student)


1. Gather the following containers: liter pitcher (filled with one liter of water), eyedropper, quart milk carton(empty), tablespoon.
2. Have enough index cards to provide each student with two.


1. The teacher tells students to pretend they just finished P.E. class on a very hot day. They are very thirsty from all the energy exerted on the playground.

2. The teacher holds up a pitcher containing one liter of water for the students to see. The teacher tells students the amount of liquid the container holds is one liter. To give students a customary unit of comparison, hold up the quart container (empty milk carton). Tell students that the quart container is close to one liter when completely full.

3. Remind students that they are pretending to be very thirsty. Ask students whether they would like to have one liter or one milliliter (most will probably pick one milliliter because they will assume it is more) to drink. Allow students to vote by a show of hands.

4. Next, hold up an eyedropper and tell students that it holds one milliliter. Tell students if they voted for one milliliter, a small amount from an eyedropper is all they would get. To give students a customary unit of comparison, hold up a tablespoon. Tell students that one tablespoon holds approximately five milliliters.

5. Write 1 liter (L) = 1,000 milliliters on the chalkboard. Tell students it would take 1,000 milliliters to equal one liter. Next, write the word -capacity- and its definition on the chalkboard. Capacity is the amount of liquid a container will hold.

6. Tell students that they are going to play an estimation game involving both liters and milliliters. Give each student two blank index cards. Instruct each to write liter on one card and milliliter on the other. Tell students you will call out names of different objects/containers. Depending on which unit of measurement is most sensible for determining capacity, each student will hold up a card with either liter or milliliter written on it.

7. Call out the objects/containers below ( answers are in parenthesis by each one ). Allow each student time to respond with his/her card. Give immediate feedback (answer) after each object/container is called out. You (teacher) can make up additional objects/containers for students to estimate the most reasonable unit of measurement for determining capacity.

bathtub (liter)
small milk carton (milliliter)
soup bowl (milliliter)
barrel (liter)
spoon (milliliter)
swimming pool (liter)
tea cup (milliliter)
baby bottle (milliliter)
water bucket (liter)
juice cup (milliliter)

8. After the game, review the following: liter, milliliter, and capacity.

9. Instruct each student to take his/her index card with liter written on it and brainstorm objects/containers that would most sensibly be measured using liters instead of milliliters. Encourage him/her to come up with new ideas. He/she is to write the names of the five objects/containers on the index card. Repeat this same activity with the milliliter card. When finished, collect cards to evaluate this lesson.


(A) Observation of student responses regarding the appropriate capacity of either liter or milliliter while playing the estimation game.
(B) Each student should get four out of five answers correct on his/her index card regarding whether liters or milliliters would most sensibly be used to determine an object/container's capacity.


1. Write incorrect sentences on the chalkboard involving liters and milliliters. Example: An eyedropper holds one liter of water (incorrect sentence). Have students rewrite these sentences so they are correct. Example: An eyedropper holds one milliliter of water (correct sentence).

2. Allow students to measure water or sand with containers marked for metric measurement. Help students see the relationship among a liter, milliliter, and other customary units of measurement. They can compare and order from least to greatest capacity and greatest to least.
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