Fifth-graders in Becky Tobin’s class at Hammond Westside Elementary Montessori conducted a scientific investigation lesson Nov. 9 to determine what factors affect the period of a pendulum.
Students tested three independent variables having to do with motion: release point, mass and length. Concepts discussed during the lesson were motion, speed, gravity, force, potential energy, kinetic energy, independent variable and dependent variables.
RELEASE POINT: Using a 6-inch ruler, students released the bob of the pendulum from a height of 6 inches above the desk. They timed the amount of time it took to complete 10 periods (10 complete swings). They performed two trials at the same height. To determine if it would swing faster if released at a higher point, students did two trials from a height of approximately 16 inches above the desk. It took the same amount of time to complete 10 periods no matter from what height the bob was released.
MASS: Students timed 10 periods of the pendulum swing using one large washer and then compared the time to two large washers. The students determined the mass did not affect the time it takes to swing.
LENGTH: Students compared the initial length, 18 inches of string with a shorter length of about 8 inches. They determined the pendulum swung much faster with the shorter string.