FORCE AND MOTION
Grade levels: can be adapted for grades 2-8.
Length of time: 40 minute or 60 minute presentations.
Room preference: Classroom or all-purpose room, e.g. auditorium, gym, or library.
Equipment is located in the Lederman Science Center. Talk to Susan Dahl to borrow this set.
- Table cloth and dinnerware (plate, glass, cup and saucer)
- Ramp structure (two ramps, two support pieces, two skateboards, two bricks)
- Balls - bowling ball and hand balls
- Objects for rolling - billiard ball, ring, disk, rod (aluminum) and ring, disk, rod (steel)
- Wooden balance scale
- Options for Newtonian Demonstrator:
Bowling ball size (5 - 16 lb. bowling balls, A-frame (5 pieces)
Best to be used for assembly-style presentation.
See power point for assembly instructions
Bocce ball size (5 bocce balls, structure top, 4 legs)
Best to be used for classroom-style presentation.
When assembling, note which color ball to attach according to abbreviations on top.
Table top size (self-contained with metal balls)
- Bicycle wheel with handles
- 2 lb. weights
- Top kit
- Toy sword
Short presentation about World Year of Physics
Inertia and Newton's Law
Use inertia demonstration by pulling a tablecloth out from under dinner ware. Discuss.
Universality of gravitational acceleration
Use ramp, skateboards and two volunteers
One student releases both skateboards
Add bricks to one, ask class which will get to the bottom first
Release and note that both arrive at the same time.
Discuss gravitational force proportional to mass, inertia proportional to mass, effects cancel out.
Remove bricks, change one ramp so slopes are different.
Ask students which setup will get the skateboard to the bottom the quickest.
Show vector diagram on parallel/perpendicular components of acceleration/force.
Summarize: Mass doesn't matter, angle does.
Drop small ball or even a feather and bowling ball from the same distance.
Rotational motion on a ramp
Ask for two new volunteers.
Use scale to show class that mass of aluminum rod and ring are the same.
Ask class to predict which one will get down quickets.
Demonstrate and discuss rotational inertia, with dominant variable (radius).
Use two rings, one aluminum and one steel and ask the class which one will arrive at the bottom first.
Demonstrate and discuss that mass doesn't matter.
Ask class what would happen if you pull one ball back and release it.
Demonstrate and discuss how some things are conserved, like a property of motion (called momentum).
Ask class what would happen if you pull two balls back. Demonstrate.
If you have a good Newtonian demonstrator, repeat . This time explaining why the motion just goes on while not in the big one.
Put rope through hole in handle. Ask a volunteer to make the wheel axis be horizontal, only touching the rope.
Spin the wheel and watch the wheel precess.
Have the teacher sword fight with you. One person has a toy sword, the other has a wheel. Don't spin the wheel.
Spin the wheel and do the sword fight.
Ask for a volunteer (under 140 lbs.) to become acquainted with the turntable. (Spin them around.)
Ask them if it matters if they have their arms out of up.
The volunteer should start spinning with their arms out, spinning slowly, then have them put their arms up.
Explain that there is a measurement of rotation (angular momentum) that doesn't change.
They should try this again with 2 lb. weights in their hands.
Explain that mass at large radius is more important.
Have student get on turntable. Spin wheel on a vertical axis. Hand it to the volunteer. Can use hand or drill to spin. Turn wheel horizontally.
Have volunteer hold wheel vertically while standing on the turntable. Have them spin the bicycle wheel and note counterrotation.
Explain angular moomentum of conservation.
Challenge a student to put a bucket of water above their head without it falling out.
Demonstrate this for the group.
Bed of Nails