Lesson 2: Simple Pendulum; Driven Pendulum

Maureen Dooley, B.S.Ed.

Copyright 2004. Permission is granted for classroom use and for non-commercial educational purposes.

Subject __________________________

Anticipatory Set (focus) - A question will be written on the board as the students walk in: How would you build a driven pendulum? The students should be told to think about the answer to this question, but they will not need to respond with an answer to this question until they have broken into pairs, later in the class period.

Purpose (objective) - The students will be able to explain what is necessary to build a driven pendulum, and they will be constructing their own simple pendulums.

Input - The teacher will explain that the students will be working on a two part activity today; for the first part they will need to pair up and brainstorm what would be necessary to build a driven pendulum. For the second part of the activity they will remain in pairs and they will attempt to build a simple pendulum.

Modeling (show) - The teacher will restate the question from the board and ask the students to work in pairs to come up with what is necessary to build a driven pendulum. For the second part of the activity the teacher will suggest building a pendulum out of everyday items.

Independent Practice - 1st The students will pair up and brainstorm what would be necessary to build a driven pendulum. The students will each write down their ideas on a piece of paper. The students will remain in pairs for 10-15 minutes. Time may be adjusted as needed.
2nd The teacher will hand each pair a paper bag containing a washer, several lengths of string, and some tape. The teacher will explain that in the bag is everything necessary to build a simple pendulum, but no further instruction as to how to build the pendulum will be given. The pairs will have 10-15 minutes to construct a simple pendulum.

Closure - (Tell or show me what you have learned)-The teacher will ask the pairs to explain what they thought would be needed to build a driven pendulum and will correct/concur with their hypothesis.
Needed for a simple pendulum: Mass, string, pivot.
Methods to drive: Push like a swing, or pull up and down on pivot.
The teacher will walk around the room to observe that all pairs have correctly constructed their pendulums. (By tying a length of string to the washer and taping the other end of the string to the side of the desk or chair or other object where the washer can swing freely.) The teacher will ask for what was different about what they thought was needed to build a driven pendulum and what they needed to build a simple pendulum.
The teacher will explain another wrinkle: The ordinary motion of the pendulum is in a plane, but it can be in a circular path, or an ellipse. To make the pendulum move in a plane for sure, much care is needed. (One method of starting is to pull the weight back with a thread and then burn the thread with a candle)
The students will correct or add to their notes on what they thought would be needed to build a pendulum. The teacher will check for understanding before moving onto the next lesson/dismissing the class.