[:PiraScheme#Mechanics: Table of Mechanics]

[:MotionIn2D: Mechanics (1D): Motion in Two Dimensions]

[:Newtons1STLaw: Mechanics (1F): Newton's First Law]

[:Demonstrations:Lecture Demonstrations]

Relative Motion

PIRA classification 1E

Grayed Demos are either not available or haven't been built yet

1E10. Moving Reference Frames


Demonstration Name



bull dozer on moving sheet (2D)

The bulldozer moves across a sheet moving at half the speed of the bulldozer or at the same speed.


moving blackboard

Using a large movable reference frame on wheels and a walking student, equations of relative speed can be deduced by non science majors.


Frames of Reference film

The classic film available on video disc permits use of selective parts.


stick on the caterpillar

A small stick placed on the top tread of a toy caterpillar moves twice as fast as the toy.


inertial reference frames

Two X-Y axes, one on a moving cart, and "cord" vectors are painted with fluorescent paint and viewed in black light.

1E20. Rotating Reference Frames


Demonstration Name



Foucault pendulum

A ceiling mounted pendulum swings freely. The change in path is noted at the end of the class period.


short Foucault pendulum

A 70 cm pendulum with a method of nullifying the precession due to ellipticity.


general and historical article

Some discussion of a current murder novel, some history of Foucault's work, etc.


Foucault pendulum model

A pendulum is mounted on a rotating turntable.


rotating frame

A monkey puppet sits on a rotating reference frame to help the student visualize a non-inertial frame.


Foucault pendulum model

Sit on a rotating chair with a table on your lab. A pendulum releasing ink marks a clear pattern on the paper.


geometric model

A geometrical model helps correct some common misconceptions about the plane of oscillation of the Foucault pendulum.


Foucault pendulum

Excellent diagram explaining the variation of rotation of the Foucault pendulum with latitude


Foucault pendulum precession

Derivation of the Foucault pendulum period shows that no correction factor is needed for (1 m) lengths. Contradicts C.L.Strong, Sci.Am. 210,136 (1964).


Foucault pendulum latitude model

A vibrating elastic steel wire pendulum demonstrates how the rotation of the plane of oscillation depends on the latitude.


Theory and two demonstrations

The concept of a locally inertial frame is used to study motion in accelerated frames. Two demonstrations are presented.


rotating room

Design for a rotating room that seats four at a table, and has four possible speeds.


catch on a rotating platform

Students try to play catch on a large rotating system. Other possibilities for the apparatus are discussed.


rotating coordinate frame visualizer

Experiments performed on a rotating frame are projected onto a screen through a rotating dove prism. Centrifugal force, Coriolis force, angular acceleration, cyclones and anticyclones, Foucault pendulum, etc.

1E30. Coriolis Effect


Demonstration Name



draw the Coriolis curve - vertical

Mount a rotating disk vertically, drive a pen on a cart at constant velocity in front of the disk. The speeds of the disk and cart are variable.


draw the Coriolis curve

Place a poster board circle on a turntable move a magic marker across in a straight line.


draw the curve

Move a magic marker in a straight line across a rotating disc.


draw the curve

A cart on a track with a marker passes in front of and draws on a large disc that can be rotated.


Coriolis ink drop letter

AJP 50(4),381 should have referenced AJP 27(6),429.



Turn a nearly vertical sheet as a drop of ink is running down it.


Coriolis machine

A clear plastic disk is placed over a inertial reference frame marked with a constant velocity path. Draw marks on the plastic disk while turning through equal angles.


Coriolis spark trace

The PSSC air puck is used to give a spark trace on a rotating table.


Coriolis gun

A spring loaded gun at the center of a 4' disc is shot at a target first at rest and then while spinning.


Coriolis gun

A clamped dart gun is fired by an instructor sitting on a revolving chair into a target board.


Coriolis gun

A spring gun at the center of a rotating table fires into a target at the edge.



Go to a merry-go-round and walk on it. You will feel a very strange "force".


spinning Coriolis globe

A ball on a string is threaded through the pole of a spinning globe. Pull on the string and the ball moves to higher latitudes and crosses the latitude lines.


Coriolis dish and TV

A ball oscillates in a spherical dish at rest, and follows various curved paths when the dish is rotated at different speeds. A TV camera is mounted to the rotating frame. More.


Coriolis rotating platform and tv

A puck is launched on a rotating platform and the motion is followed with a TV


Coriolis effect

Roll a ball across a slowly rotating turntable.


leaky bucket on turntable

A can with a hole is mounted above a rotating table. As the table turns, the stream of water is deflected.


drop ball on turntable

A mass falls on a disc first while it is rotating and then when it is stationary. Difference in point of impact is noted.


Coriolis trajectory

A ball describing an arc is released first in a stationary coordination system and then in a rotating system.


Coriolis water table

A flat board rotates in a horizontal plane with a flexible tube full of flowing water running lengthwise. The tube deflects upon rotation.


Coriolis water table

A flexible rubber tube with water flowing in it is stretched across a disc which can be rotated. The tube deflects when rotated.


Coriolis water table

A flexible rubber tube with water flowing in it is stretched across a disc which can be rotated. The tube deflects.


rotating water flow table

Food coloring used to mark flow is introduced at the edges of a circular rotating tank with a center drain hole. A rotating overhead TV camera allows motion in the rotating frame to be viewed.



A pan of water on a turntable has a recirculating pump with an inlet and exit of opposite sides of the pan. Floats above these areas rotate in opposite directions as the pan of water is spun.


rotating TV camera


rotating TV camera

A TV camera is rotated in front of an oscilloscope displaying a slow ellipse. Vary the camera rotation.


vacuum cleaner

Cover the exhaust of an old vacuum: the current decreases as the RPM increases. Demonstrates transformation of vectors from a moving coordinate system to a rest frame. In one frame the torque does no work, in the other with open exhaust torque is responsible for the entire power.


spinning dancer - Coriolis analysis

The spinning dancer, usually treated as an angular momentum problem, is used as a Coriolis example.