Measuring Volume

 

Objectives: After completing the lesson, students will be able to:

  measure the volume of an object using three methods: displacement, capacity, and direct measurement

 

Key Question: "How do we measure the volume of an object?"

 

Overview: Students learn to measure an object's volume using three separate methods. They fill an object with liquid, measuring the capacity (in milliliters) of the object, using a graduated cylinder. They measure the length, width, and height of a rectangular prism, to find the volume of the object by direct measurement  (in cubic centimeters) and multiplication. They then build a device out of a plastic, 2 liter soda bottle, that allows them to measure the displacement  (in milliliters) of an object.

 

Time Required: 45-60 minutes (1 class session).

 

Materials:

for each group of 3-4 students


2 liter, plastic soda bottle

  graduated cylinder

  metric ruler

  a variety of small objects shaped like a rectangular prism

  water

  large bus tray


 

clear, plastic cup

  a variety of thin walled objects that can be filled with water

  scissors

  permanent marker


 

for each student

  a copy of "How to Use a Balance," pp. 7-10 in Focus on Earth Science: Laboratory Manual

  a copy of "Measuring: Mass," p. 32 in Inquiry Skills Activity Book

  a copy of "Measuring: Temperature," p. 33 in Inquiry Skills Activity Book

 

Procedure:

            Review with students the procedure for correctly measuring volume using a graduated cylinder (see homework in Lesson 21--My Favorite Stuffed Animal). Stress that the units are milliliters. Students should then determine the volume of an object by filling it with as much water as the object can hold (capacity), and measuring the amount of water with the graduated cylinder.

            Have students next measure the length, width, and height of a rectangular prism. They next multiply these direct measurements together (length x width x height), to determine the volume of the object in cubic centimeters.

            Finally, have students construct a displacement measurement tool out of a plastic, two liter soda bottle (see the diagram below). They fill the measurement tool with water, until it starts to run down the "chute" they have created. Have them place a cup under the chute to catch the water that is "displaced" from the soda bottle when an object is placed in the water. They then measure the water collected in the cup in their graduated cylinders, to determine (in millimeters) the volume of water the object has displaced. Remind the students that one cubic centimeter represents the same volume as one millimeter. They can confirm this relationship for themselves if you can find a rectangular prism that has no top side (such as an orange juice or milk carton with the top half evenly cut off).

 

Assessment:

  accuracy of measurements

  completion of homework questions

 

Homework:

  read "How to Use a Balance," pp. 7-10 in Focus on Earth Science: Laboratory Manual, and answer the study questions

  read "Measuring: Mass," p. 32 in Inquiry Skills Activity Book, and answer the study questions

  read "Measuring: Temperature," p. 33 in Inquiry Skills Activity Book, and answer the study questions

 

OUSD Science Content Standards (State of  California Science Content Standards): 

#1-b (7-b)

References:

Focus on Earth Science: Laboratory Manual. Upper Saddle River, New Jersey: Prentice-Hall Inc., 2001, pp. 7-10.

 

Inquiry Skills Activity Book. Upper Saddle River, New Jersey: Prentice-Hall, Inc., 2001, pp. 32-33.

 

Notes: It is a good idea to discuss with the students why there are three different methods for measuring volume, and what types of situations in real life require each of the three methods. It is worth reminding the students that cubic centimeters are the same as milliliters because water was used as the reference substance when the metric system was created. In other words, a milliliter was defined initially as the amount of water contained in a one cubic centimeter cube. A gram was defined initially as the amount of water contained in this one centimeter cube.

Key Vocabulary:

capacity: the amount of liquid an object can hold.

 

direct measurement: finding the volume of a rectangular prism by multiplying the length of the object by its height of the object, and then multiplying the product times the width of the object. It is important that the measurements for length, width, and height are taken using the same units.

 

displacement: the volume of water that an object "pushes aside," or displacements when submersed completely under water.