• "Monkey Hunter" demonstration including blow gun, steel ball, magnet & target
  • Second law of motion apparatus propels one ball horizontally while dropping another vertically at the same instant (Cenco #75345).

Newton's 3rd Law - Colliding Cars

  • Colliding homemade cars equipped with Pasco force sensors interfaced to a computer

Angular Momentum

  • Euler's Disk - 1/2" thick, 3" diameter chrome plated steel disk spinning on edge on a concave mirror base

Rotational Motion

  • Turntable, stool, and weights

Moment of Inertia 

  • Rolling ring and disc down an inclined plane; similar to Cenco #75255; plus mechanical device (designed by J. Hunt) to simulate rolling disc or liquid or soup can; plus lucite cylinder which can be filled with water and rolled down plane
  • Brick suspended by recording tape


  • Electric gyroscope - similar to Cenco #74730
  • Rotating stool and bicycle wheel
  • Gyro-Ring :  5 little tops of unusual design strung on a metal ring
  • Dynabee/Dyna-Flex/Supergyro - handheld gyro exercisers in which the rotor can be accelerated to high revs by simple wrist movement

Centripetal Force Demonstrator

  • 2 jars mounted on ends of horizontal bar free to rotate on its stand; float attached by short cord inside each jar forms an inverted pendulum when jar is filled with water; similar to Sargent-Welch #0922

Center of Mass

  • Balancing man
  • Belt holder
  • 3 weighted aluminum tubes


  • Wooden arm with rope handles pivoting about fixed point

Newton's Cradle

(Conservation of Momentum)

  • Six steel balls suspended from a frame to perform elastic collisions

Torsion Pendulum

  • Two foot steel wire running from a rod to a flat round disk


  • String with 50 gram weight attached runs over 2 pulleys to 100 gram weight on the other end; protractor is used to measure angle of swing required to lift 100 gram weight slightly off table

Falling Faster than "g"

  • Pair of hinged boards with cup; steel ball tee on top board

Breaking Broomstick (Inertia)

  • Special wood dowel with pin in each end balanced between 2 wine glasses; dowel is broken in half with no effect on glasses

Egg Crusher

  • Demonstrates ability of egg to support large forces due to its curved shape

Ice Demonstration

  • Wire passes through a block of ice and ice remains intact

Scaling Model

  • Small wood "cow" with barely adequate legs to stand on and another scaled up by a factor of 5 which collapses

Strobed Disk

  • Strobe, motor, black and white circular disk


  • For use on overhead or table; has counterclockwise spin bias and magnifying properties

A Precessing Orbit

  • Ballbearing rolling in an acrylic hemispherical dome

Blood Vessel Model

  • Device to show stretching of elastin and collagen in blood vessel walls - 2 handles attached to wooden pieces between which are short alternating strands of black neoprene 'O'-ring material and clear vinyl tubing.

Multiple Collision Accelerator

  • Illustrates the laws of conservation of momentum and energy.  Also simulates the creation of a supernova.  Arbor Scientific Astro Blaster - 4 superballs on guide rod; when dropped vertically, top ball projected up to 5 times the height of the drop.

Circular Orbits of Ball on Rotating Turntable

  • Spinning turntable with raquetball.

Dynamic Balancing

  • Rod with 2 separate holes drilled through to allow it to spin about the axis of another fixed rod


  • The Pira resource directory for mechanics.

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