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Issue link: https://wardsworld.wardsci.com/i/1510313
Page 2 + ward ' s science Happy/Sad Balls Investigation (continued) Variety of materials to choose from: • Clear plastic cups • Ice • Paper towels • Cooler for ice • Hot water/tea kettle • Hot hands or potholders • Celsius thermometers • Hair dryer • Ramps or inclined planes • Meter sticks or measuring tapes • Compact digital scale or triple beam balance • Timing device Activity Setup: This lesson is designed to allow students to use scientific practices to plan and conduct descriptive, comparative, and/or experimental investigations. The teacher's role is to provide guidance and supplies but ultimately, the students will collaborate with their group to develop a cause-and-effect comparative and/or experimental investigation. Background Information: • After observing the two spheres, students will notice one ball bounces and one ball stays on the ground. Happy and sad balls are black spheres which appear to be almost identical. They have the same color, size, texture, and shape. Why do they behave differently? • The "happy" ball is made from polychloroprene (neoprene rubber). Polychloroprene is a synthetic rubber product. Polychlo- roprene is generally stronger and harder than natural rubber and more resistant to water, oils, and solvents. Polychloroprene is very bouncy—it stores very little energy in collisions and bounces well, or it snaps back to shape quickly. It is used to make wetsuits, and automobile parts, such as fan belts, hose covers, and shock absorber seals. • The "unhappy or sad" ball is made of polynorbornene (norsorex rubber), it stores a lot of energy and does not bounce well. Polynorbornene is used mainly in the rubber industry for antivibration, anti-impact equipment, shoe parts, bumpers, golf balls and snow tires. Step-by-Step Procedure: 1. Divide students into groups of 3–4. 2. Engage your students with the following event: a. Teacher Demo: Drop the two balls from the same height. 3. Have students work with their group to observe, describe, and hypothesize causes. 4. Have a whole group discussion, allow 2–3 students to share their thoughts on the cause of this behavior. 5. Ask the following question: a. What questions do you have now? b. What questions might a scientist ask about the behavior of the spheres? 6. Give each group a set of balls and a Happy/Sad Balls Investigation Student Data Sheet. Have them complete the chart as they observe the physical properties of the 2 spheres. Adjust the physical properties per grade level (density and volume may be added for MS). Set the timer for 5–10 minutes.