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This activity will help students discover that the total weight of an object is equal to the weight of its individual parts after being disassembled.
For Invitation to Learn:
“No matter how parts of an object are assembled, the weight of the whole object is always the same as the sum of the parts; and when a thing is broken into parts, the parts have the same total weight as the original thing. It is not obvious to elementary students that a whole weighs the same as the sum of its parts.” (The Structure of Matter: 3-5; AAAS Benchmarks) The following experiences will help your students to understand this relationship between wholes and their parts.
These activities are best done by small groups of 3-5 students. It is important that each group has access to a scale that can accurately measure 1-gram increments. If scales are not available, the activities can be done as a teacher demonstration.
1-Use science process and thinking skills
4-Communicate effectively using science language and reasoning.
Invitation to Learn:
Show the class a ball of modeling clay and have them name its physical properties. List their responses on the board. Remind students that weight is a physical property. Allow students to hold the ball and then have them make estimates of the clay 's weight. Record their estimates on the board. Weigh the ball of clay and compare it to their estimates. Record the
clay's weight on the board.
From the large ball of clay, break off a smaller ball for each team, and have the class list the properties of the smaller balls. (Students should notice that all the properties of the clay are the same except the size and weight of each ball has changed.) Have each team weigh their ball of clay and report its weight. Record the weights on the board.
Collect all the clay and mold it back into a large ball. Ask the teams to put their heads together and decide what they think the large ball of clay weighs. Have teams report the weight and explain how they arrived at it. Record responses. Weigh the clay and compare the weight to the teams' guesses and the weight of the original ball of clay. (The re-formed ball of clay will probably weigh less than the original ball because some of the clay will remain on the students' hands or desk tops. Ask the class to explain why the re-formed ball weighs less.) Tell the class they are going to further investigate the relationship between the weight of the whole and its parts.
Cooperative teams of 3-5 should complete the following procedures: (see Team Procedures)
After students have completed the activity, have the teams share with the class what they have learned. Discuss the statement: The weight of the arts is always equal to the weight of the whole. Is this statement always true? Can you think of a time when it may not be true? Can it be tested? How? What are some investigations that you could do to test the statement? You may wish to allow students to set up other investigations to test the statement.
shavings (bag holding shavings) + used pencils + graphite and erasers not collected = total new weight of pencils.
Have students fill in the values and solve for the graphite & erasers.
Use this rubric to assess your students ' performances:
Student 's Name ____________________________________
||Descriptions and data clear and accurate. All observations
|Descriptions and data mostly clear and accurate. All observations
|Descriptions and data somewhat clear and accurate. All obervations
|Descriptions and data unclear and inaccurate. All
|Used time well and focused attention on the activity.
||Used time fairly well. Stayed focused on the activity most
of the time.
||Did the activity but did not appear very interested. Focus
was lost on several occasions.
||Participation was minimal OR student seemed negative about participating.|
This lesson is part of the Fifth Grade Science Teacher Resource Book (TRB3) http://www.usoe.org/curr/science/core/5th/TRB5/. The TRB3 is designed to be your textbook in teaching science curriculum to your students. This book covers all the objectives of each standard and benchmark. If taught efficiently, a student should do well on the End-of-Level (CRT) tests. The TRB3 is designed for teachers who know very little about science, as well as for teachers who have a broad understanding of science.