Lesson 7: Motion - 2
(develop understanding of acceleration)
Grades: 8 - 12
| Possible Questions
Why do different parts of a Rickey sculpture move at different speeds?
What causes acceleration in Rickey sculptures?
How do the forces of gravity and wind change the directions of motion?
The goal of this lesson is to help the students’ understanding of Newton’s laws of motion
- so this can become more analytical at the higher grades.
The Rickey sculptures principally involve non-uniform circular motion (e.g. unlike most merry-go-rounds).
Hence, the introductory discussion should focus on the complexity of these motions, and how circular and linear motions might be separated,
and how the directions of the forces vary.
This separation of types of motion can then be developed in the group hands-on part of the lesson
Half the groups can build a model illustrating circular motion, the other half can do a linear motion experiment
- they should be able to develop the ideas, but helpful ideas could be given: e.g for circular motion:
a pendulum, a see-saw, a Rickey-like sculpture, twirling a rock-on-a-string - note that for most of these the force is varying.
For linear motion, a car or stone on a ramp (could vary the angle or the car or the texture of the ramp); or a person running or walking.
For all these experiments a motion detector (Labquests are in many South Bend schools) would be useful.
Summing up the experience: The groups need to compare and contrast their various results:
discuss the type of motion they made - circular or linear or varying or constant.
Can they understand the relationships between position, speed, velocity, and acceleration?
Extensions: Analyzing the motion of any familiar object:
the earth going around the sun, the moon around the earth, a car going from South Bend to New York (with stops).
Graphing position and velocity to understand slopes of straight lines and curves.