Juggling Makes Physics Fun: Elementary Students Learn the Physical Science Concepts Behind Juggling
Beck, Charles, Science and Children
We all hope our classrooms don't take on a circuslike atmosphere, but juggling can be an engaging way to introduce elementary physics to students. After presenting simple juggling demonstrations to my fifth- and sixth-grade students, I encouraged them to try juggling objects such as floating scarves, beanbags, and tennis balls. They soon learned that they had to control the direction, amount of force, and distance between the objects. The students were overjoyed when they learned to keep the objects in motion without dropping them. The very act of tossing and catching objects helped students to understand the basic physical principles involved in rotating a set of objects.
This article suggests a variety of simple hands-on activities and demonstrations for introducing physical science concepts associated with juggling. The goals of these exercises are as follows:
* To help students understand the juggling skills required to keep a set of rotating objects under control and in a predictable pattern.
* To suggest a simple set of tossing, dropping, and catching exercises designed to help students literally grasp a set of juggling concepts.
* To help students understand how balancing a set of stationary objects on a lever is analogous to balancing objects in motion.
* To provide several simple juggling routines designed to make the concepts and principles of juggling more tangible and meaningful.
The exercises in Figure 1 (p. 30) are designed to help clarify some key physical science concepts involved in juggling, such as force, motion, gravity, mass, and velocity. They are particularly helpful in demonstrating how mass and force affect rotating objects. Many upper-grade elementary students have already been introduced to many of these concepts based on their knowledge of simple machines. Before beginning the exercises, one or two volunteers can help demonstrate each of the concepts. For example, force can be shown by tossing a ball upward and observing how the force of gravity pulls the ball downward. Students can also observe how the upward velocity decreases as the object moves toward its apex and how objects with more mass require greater force to propel them upward than objects of less mass. For more information on the basic concepts and physics of juggling, see Internet Resources.
The hands-on exercises are simple to perform and do not require any ability to juggle. The teacher might want to divide the class into six groups and assign a different exercise to each group. Before beginning the exercise, ask the students to think about the question and predict the outcome. After the members of each group have had an opportunity to practice the exercise, rotate the groups until they have experienced all six exercises. After the groups have completed all of the exercises, ask them to summarize what they have learned from each exercise in the form of a conclusion.
Preparing Students to Juggle
Before the students learn how to juggle, invite someone who can juggle to visit your class. Because students can learn to juggle at a very early age, there is a strong likelihood that at least a few students in the school can juggle two or three balls. During the demonstration, encourage the class to carefully observe the position of the juggler's hands, arms, legs, and the objects being juggled. They should notice that each object is the same size and weight and small enough to grasp within the palm of the hand. They will also likely notice that the upward tossed object reaches about eye level and that the juggler's eyes are focused on the elevated object and not on the hands. After observing a live demonstration, the teacher should ask the students the following questions based on their observations:
* Why is it important to toss each object upward in front of the juggler at about eye level? …