Lesson 4

Measuring Mass

Est. Class Sessions: 3

Summarizing the Lesson

Ask students to display the rocks that they brought from home. The rocks should be about 50 grams. Have students work with a partner to check the accuracy of their estimations by using zeroed two-pan balances and standard masses to find the rocks’ exact masses. As students are measuring, circulate around the room and assist as needed. If you are able to find a rock that is smaller in size, but has a mass that is greater than other rocks larger in size, take note. You can use it to illustrate a key concept that material is an important variable in determining mass. For example, depending on what an object is made of, smaller objects can have more mass than larger ones.

Students should record the mass on the Pet Rock page in the Student Activity Book. Next, ask student pairs to compare masses.

Ask:

X
  • Whose rock has the greater mass?
  • What is its mass?
  • What is the mass of the other rock?
  • What label do you need to include when reporting the mass of the rocks? (grams)
  • Whose rock is closer to 50 grams? How do
    you know?
  • Do you think a small object could have a large mass? Explain.

If you were able to find a small rock with a mass greater than a large-size rock, point this out to students. Display the rocks and use the two-pan balance to show students that the small rock has a greater mass than the other rock. If you were unable to find one, compare a large marshmallow or a cotton ball to a rock that is smaller in size, but greater in mass.

Ask:

X
  • Are the objects the same shape?
  • Do they appear to be the same size?
  • Are they made of the same material?
  • Does only the size of an object determine its mass? Because an object is bigger, like the [cotton ball, marshmallow], does that mean it has more mass than this small rock? (No; we have to think about what the objects are made of, too.)

Assign the Pet Rock page in the Student Activity Book. Tell students they will solve problems using the mass of their rock.

X

Use the Pet Rock pages in the Student Activity Book to assess students’ abilities to compose and decompose numbers using ones, fives, and tens [E1]; recognize that different partitions of a number have the same total [E4]; apply the properties of addition (e.g., commutative, associative) to write number sentences that represent mass [E5]; and use labels [MPE6].

Adventure Book:
Student Activity Book: 413 414
Answers
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SAB_Mini
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X
SAB_Mini
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Master: