Use a ball on string to demonstrate circular motion.
Location: Ball on String – ME2A-26-1
Prep time: none
Hold the whirligig horizontal by the metal bar. Notice the large mass falls straight down. Now whirl the nut around and the large mass doesn’t fall. Whirl faster and the large mass rises.
Location: Whirligig – ME2A-27-1
Prep time: none
Swing a pail of water overhead to demonstrate centripetal force. Have a student see how slow they can swing the bucket before the water begins to fall out.
Location: ME0B-74-1
Prep Time: none
Have a student sit on the stool with their arms extended and weights in hand. Give them a push and watch them turn. While turning have the student slowly bring their arms toward their chest. Note the difference in rate of turn.
Location: Stool -
ME0G-58-2
kg weights - ME0G-59-3
Prep Time: none
Use the set of wheels and stand to demonstrate the effects of radius on a rotating object. The ropes are the same length and have equal masses at the ends. You may also relate radius to arc length.
Location: Wheels –
ME0G-57-2
Stand – C2-08-2
Prep Time: none
Take the funnel and role a marble around its side. As the marble goes further and further down the funnel its speed increases due to conservation of angular momentum.
Location: Funnel - ME2F-24-2
Marbles - ME2F-24-2
Prep Time: none
Use a yo-yo to demonstrate conservation of angular momentum.
Location: Yo-yo - ME2B-25-1
Prep Time: none
Use an old fashion top to demonstrate circular motion.
Location: Top – ME2A-28-1
Prep time: none
Use the tops to demonstrate rotational motion and the stability of spinning objects. The top on the right with the house shaped tip has an internal flywheel, which allows the top to remain stable while appearing to be motionless. Run the tip along the table to start the flywheel in motion.
Location: Tops- ME2B-61-1
Prep Time: none
The bicycle wheel can be used to demonstrate the stability of rotating objects. Hold the wheel vertically and make it spin very fast. If you hold the rope and drop the wheel, the wheel will remain vertical. Have a student hold the wheel vertically while it is spinning. Tell them to try to jerk the wheel over their head. They will find this very difficult.
Location: Wheels – ME0G-58-2
Prep Time: none
Have a student sit on the stool. Get the wheel spinning and hand it to the student. Have the student twist the wheel 90 degrees. You will see the student start spinning on the stool.
Location: Wheels –
ME0G-58-2
Stool – ME0G-58-2
Prep Time: none
A bear is supported at its center by a bar and rubber band, which is enclosed within a wheel. As the wheel is set in motion the bear remains motionless with respect to the wheel, as its center of mass is located beneath the pivot. HOWEVER, as the bear continues to roll the rubber band becomes twisted causing the wheel to stop and roll in the opposite direction. You may want to quiz the students before explaining this demonstration. This demo is most effective when done on the floor as it takes almost 10 feet to stop and change direction. Trick the students into thinking an unleveled floor is the cause by stopping the bear after one change of direction. Then do it again to prove them wrong.
Location: Bear- ME2B-64-1
Prep Time: none
To demonstrate centripetal force use the thin walled hollow plastic spheres. You can adjust the length of the strings at the handle. Hold one ball and let the other ball hang free. Now swing the free ball in order to begin a counterclockwise rotation. Once the free ball has a stable orbit set the hand held ball in clockwise rotation. In order to sustain the motion, move the handle up and down, not in a circle. This takes practice.
Location: Balls, string and handle - ME2B-65-1
Prep Time: practice
Spin the book about its three principle axes. The book will be stable when spinning about the axes with maximum and minimum moments of inertia. The book will not be stable spinning about the axis with the intermediate moment.
Location: Book – ME3B-60-1
Prep Time: none
Take a broomstick and put two pins in the ends of the sticks. Mark the exact middle of the stick. Fill two wine glasses with water or red liquid. Using the pins, place the broomstick on the wineglasses. With a metal rod break the broomstick exactly in the middle while swinging straight down at the point of impact. Remarkably the wineglasses don’t break. (Swing hard!)
Location: Broom stick – ME0D-29-3
Wine glasses – ME3A-29-3
Metal rod – ME0D-29-3
Prep time: 10 minutes
