An object rolling down a hill acquires both translational and rotational kinetic energy. One must take the rotational kinetic energy into account when calculating the object's velocity at the bottom of the hill Read more about Rolling Down an Incline
The photoemission of electrons from a metal surface depends on the energy of the incident radiation and not on its intensity. Knowing the energy of the emitted photoelectrons and the frequency of the incident light, you can calculate a value for Planck's constant h. Read more about Planck's Constant Determination
The full spectrum of colors (including white) in a television picture is produced by the additive mixing of only three colors: red, green, and blue.
How it works:
In a color television tube, three separate electron beams are focused so as to strike the appropriate phosphor dot on the screen. By looking at the television screen under considerable magnification, one can clearly see that there are only three phosphors which are stimulated by the electron beam(s). The apparatus is diagrammed below. Read more about TV Color Perception
Sodium 'D' line absorption showing up as a black line in the yellow of a continuous spectrum. Good as a simulation of the sodium portion of the Fraunhoffer absorption spectrum caused by atoms in the solar atmosphere; it does not however, resolve the 5890/5896Å doublet. Read more about Sodium Absorption
Radio controlled car moves one way while road moves the other.
What it shows:
We tell our students that, when a car drives down the road, the road and the Earth move in the opposite direction, albeit imperceptibly. This demonstration is a realization of that concept, made possible (and perceptible) by the fact that the road is not attached to the Earth. Read more about Reactionary Roadbed
A lecturer's faith in the principle that an electric field cannot exist inside a charged conductor is put to the test using a Faraday cage that is large enough to sit in. Read more about Walk-In Faraday Cage