[L | t+ | ★★★]
Air table with fixed magnetic puck to represent nucleus scatters "projectile" magnetic pucks.
Rutherford Scattering Model with Van de Graaff
[M | t+ | —]
Charged Christmas tree balls scatter off of Van de Graaff.
Rutherford Scattering Model with Ping Pong Balls
[L | t+ | —]
Ping Pong ball projectiles scatter off of a sphere and into buckets set at different distances (scattering angles).
Potential Well Orbiter
[M | t | ★]
Orbital motion simulated by ball rolling on wooden potential well.
Roller Coaster Potential
[M | t | —]
One-dimensional model of electron trapped in atomic potential well.
Giant Nuclear Potential Well
[M | t | —]
Use a hammer to enable a ball to overcome potential barrier.
CRT Paddle Wheel
[S | t+ | —]
A beam of cathode rays (electrons) impinging on a paddle wheel cause it to spin and travel down the vacuum tube.
Determination of e/m
[L | t++ | —]
Charge to mass ratio of electron, using electron beam in magnetic field of Helmholtz coils.
JJ Thomson e/m Tube
[S | t++ | —]
Similar to preceding demo but the geometry is similar to Thomson's original experiment.
Cathode Ray Deflection
[M | t | ★★★★]
Small Crookes tube with built-in fluorescent screen shows electron beam deflection by magnetic field.
Maltese Cross CRT
[M | t | ★★★]
Maltese cross obstacle and fluorescing glass show that electrons in a Crookes tube travel in straight lines and are affected by magnetic fields.
TV Image Deflection
[L | t+ | ★★]
Image on black and white television is deflected by a magnet, not unlike the Maltese Cross.
Bremsstrahlung and X-Rays
[M | t+ | ★★★]
X-rays are given off by the stopping of electrons in the Maltese Cross CRT; a glass plate in front of detector shows they are "soft" x-rays.
NMR in Earth's Magnetic Field
[L | t+++ | —]
Hear the protons sing their FID! NMR frequency is in the audio range for earth's field. Videotape of actual experiment.
[M | t+ | —]
Gyro (with axially mounted magnets) positioned inside Helmholtz coils; field is switched by hand at "Larmor frequency" to flip the spinning gyro.
Reversible Fluid Mixing
[M | t+ | ★★★★]
Surprising reversibility at low Reynolds number. Also a mechanical analog of spin echoes in NMR.
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