#  Rotational Dynamics (centripetal forces and rotating reference frames) 

 



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### Tennis Ball on a String

\[M | t | —\]  
Whirl it around and then let go.

### Loop-the-loop

\[M | t+ | ★★★\]  
A toy car rolling down a loop-the-loop track demonstrates the minimum height it must start at to successfully negotiate the loop. Can also be performed with small pendulum  
  
\[[In-Depth Description](/presentations/loop-loop)\]

### Barrel of Fun

\[L | t+ | ★★\]   
Turntable model of amusement park ride to investigate angular velocities necessary to keep objects pinned to wall.   
  
\[[In-Depth Description](/presentations/barrel-fun)\]

### Bucket of Water

\[M | t | ★★\]   
A bucket, partially filled with water, is swung in a vertical circle at arms length without spilling a drop.   
  
\[[In-Depth Description](/presentations/bucket-water)\]

### Olive-Wineglass Puzzler

\[S/M | t+ | —\]   
The trick is to pick up an olive with an inverted wineglass and transfer it to another.   
  
\[[In-Depth Description](/presentations/olive-wineglass-puzzler)\]

### Motor Driven Turntable

\[L | t+ | —\]  
A row of weights, aligned on the radius of the turntable, come flying off as rate of rotation is increased.   
  
\[[In-Depth Description](/presentations/motor-driven-turntable)\]

### Centripetal Force Puzzler

\[S/M | t | —\]  
Tethered, floating balls move radially *inward* on rotating turntable, contrary to intuition; also done with candle flame.  
  
\[[In-Depth Description](/presentations/centripetal-force-puzzler)\]

### Coriolis Force

\[XL | t+ | ★★★\]  
Students try to throw a volley ball to each other or into a basket while sitting on a rotating platform; lots of fun  
  
\[[In-Depth Description](/presentations/coriolis-force)\]

### Foucault Pendulum Model

\[M | t++ | ★★\]  
A "working model" of a Foucault pendulum to show how its oscillations appear to change due to the rotation of "Earth" below it.  
  
\[[In-Depth Description](/presentations/foucault-pendulum-model)\]

### Foucault Pendulum

\[L | t+++ | ★★\]  
Plane of pendulum oscillation appears to change due to rotation of Earth.  
  
\[[In-Depth Description](/presentations/foucault-pendulum)\]

### Contact Us

**Mailing Address**: Lecture Demonstration Services, Science Center, Rm B-08A, 1 Oxford Street, Cambridge, MA 02138  
**Campus Location**: Science Center B-08A | **Tel**: (617) 495-5824 | **Email**: scidemos-at-fas.harvard.edu