Balance and Weighing Name ____________________________

Balancing and Weighing is a 17-lesson unit designed for second graders In lessons 1-5, they explore ways to create balance and use a beam balance. In lessons 6-9, students compare objects using an equal-arm balance. In lesson 10, students are introduced to weighing with the equal-arm balance, and they record weights in data tables. In lesson 11, students use the recorded weights from lesson 10 to make bar graphs. In lessons 12-15, students use their skills to investigate problems dealing with the weights and volumes of four foods. In lesson 16, students use the skills and concepts they have developed to solve a mystery. In lesson 17, students assess what they have learned about balancing.

Balance Engagement Have you been on a skateboard? Let’s observe how a skateboard can help you balance. on_math/skateboard_flex.php

List ways to balance… Ways to balance

Lesson 1 Thinking about Balance Have teams balance the butterfly figure on the pencil eraser. Give out the jumbo paper clips. Have them attach the paper clip to the butterfly. How does this change the balance? Record in Balance and Weighing notebook

Lesson 2 Building Structures that Balance Give out the beam, fulcrum, and connecting cubes. Ask the students to use these materials to build structures. Have students draw their structures in their Balance and Weighing notebook. Choose several student to draw on the board and share their steps for balancing.

Lesson 3 Exploring the Beam Students explore the relationship between balance and mass by varying the number and position of connecting cubes.

Lesson 3 Exploring the Beam Balance Demonstrate the balance beam with the beam balanced on the fulcrum. Refer to Procedure on p. 18. Have them try different combinations of 10 cubes to balance the beam. Have participants fill in Record Sheet 3-A. *Ask the questions under Final Activities steps 1and 2 on p. 19.

Julie’s Balancing Act Optional: Have them read “Julie’s Balancing Act” ( Reading Selection p ). Ask, “What are some ways you might relate this story to the activities you just completed?” “How might you relate this story to things you do?”

Lesson 4 Moving the Fulcrum Note that the focus of this lesson is moving the fulcrum to obtain balance. Draw attention to Record Sheet 4-A. Ask the teams to make an “x” on the beam in each drawing to indicate where they predict the fulcrum should be placed to create balance. Then let them test their predictions. * Point out the Note under step 2 on p. 29 that recommends moving the beam instead of the fulcrum.

Lesson 5 Building Mobiles Teams gather paper clips, red squares, straws, beam and tape or text book.

Mobile Engagement

Glossary Alike: Acting or looking the same. Balance: A tool used to compare weights. Beam balance: A device used to compare the weight of two objects. A beam balance consists of a beam and a fulcrum. The position of the fulcrum can be changed, and the weights can be placed anywhere on the beam. Brainstorm: To share ideas on a topic. People often brainstorm to solve a problem. Communicate: To share information and ideas through speaking, writing, or drawing. Compare: To look at two or more things to see how they are alike or different. Data: Information, such as that gathered during an experiment.

Equal-arm balance: A device used to compare the weight of two objects. The position of the fulcrum and the position of the weights are fixed. Experiment: A procedure that is carried out to investigate a scientific question. Fair test: A test that compares two or more things by keeping everything the same except the thing being compared. A race is a fair test. Everyone starts at the same place and at the same time and ends at the same place. The only thing that is different is the speed of the runners. Fulcrum: The support on which a beam balance rests; the support on which a lever turns Graph: A diagram used to show the relationship between things. Guess: To give an idea about something when you are not sure.

Investigate: To study something closely and in an organized way. Length: The distance from one end of something to the other. Line plot: A type of graph. Measure: To find out the length, size, or weight of something. Mobile: A hanging piece of art. It is made up of many parts that are balanced at different positions. Object: Something you can see or feel. Observe: To use your senses to study something closely. Pattern: A repeating arrangement of shapes, colors, numbers, or other things. Plot: To locate a point or points on a graph.