`BoomerangWilhelm L. Lilly               Kenwood Academy High School                               5015 S. Blackstone Ave.                               Chicago IL 60615                               (312) 535-1409Objectives:    This lesson can be effectively used with grades 4-12.* Estimation of angles in degrees.* Estimation of distances in feet or meters.* Data collection and histogram analysis.* (optional) Study gyroscopic precession and aerodynamics.Materials Needed:* Two 12-inch rulers (shatter-resistant) per group/student.* Rubber bands and/or strong tape.* Protractor per group/student.* TI-81/82 per group.* Data collection sheet per group.* Two skewers or sticks with marker flags per group.* One yard or meter stick per group.Recommended Strategy:   Have students form groups of two.  Discuss with students how a boomerang is designed to return when thrown (Australia and geography can be included).  Show how to make a boomerang by crossing two rulers and holding them together with crisscross rubber bands or tape.  Demonstrate how a boomerang is thrown over-hand like a baseball.  Show arm positions as: straight-up/vertical (zero-degrees); shifted to the side (30-degrees); shifted to the side (60-degrees); and shifted to the side/horizontal (90-degrees).  Distribute two rulers, rubber bands or tape, protractor, yard/or meter stick, two skewer markers, and a data collection sheet to each group.  After each group has made their "X" shaped boomerang, explain that each group must measure and mark a distance of 20 yards as a throwing range.  Each student will have three throws in each of the arm-shifted positions: 0, 30, 60, and 90 degrees.  Their group partner will record the estimated maximum distance reached for each throw and did it return or not. Take the students outside and assist them with the activity/data collection.    When the data collection sheets are complete return inside and use the data to create a histogram for angles thrown and distance reached.  TI81/82 calculators can be used to assist students in making histograms and analysis of data.  Have each group explain their histogram and their conclusions regarding whether or not angle thrown effects the flight of their boomerang.  Other factors such as wing profile, air resistance, force thrown can be discussed. Lesson can be extended by introducing the concept of gyroscopic precession, which is the physics principle causing a boomerang to return (possible library assignment).  `