The instructor breaks several boards with a swift blow of the hand.
What it shows:
The impulse momentum theorem is demonstrated in a most dramatic way by breaking several boards with the blow of your fist. You need not be a karate expert to show how the force of a well executed hammer-fist strike will easily break a stack of five to eight boards. The impulse is given by
impulse = F∆t = ∆mv
The point of the demonstration is: the greater the speed, the smaller ∆t will be and thus the greater the force.
How does shielding work? Is it a two-way street and work both ways? Can electric fields not penetrate metals? What's going on? This sequence of demonstrations addresses these questions.... Read more about Electrostatic Shielding
Wave/particle duality observed in Young's double slit experiment with camera sensitive to individual photons.
What it shows: In this demonstration we perform the double-slit interference experiment with extremely dim light and show that even when the light intensity is reduced down to several photons/sec, the audience can see the familiar Young's double-slit interference pattern build up over a period of time. This addresses the question of how can single photons interfere with photons that have already gone through the apparatus in the past, or with those that...
What it shows: The intensity of light from a point source decreases as 1/r2, where r is the distance from the source.
How it works: For the point light source, we use a 1500 watt clear light bulb. The detector is a small solar panel.1 The output current is directly proportional to the intensity of the light falling on the panel and the current is displayed on an analog milliameter. (The current can also be measured by a digital meter or computer.) Measured...
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.
How it works:
The lecturer (or some volunteer) climbs the three steps and sits upon a plain wooden chair. Their assistant pulls the mesh door closed and fastens it. A Van de Graaff, whose dome is in contact with the cage, begins to charge itself and the cage up to a high voltage. The person inside is oblivious to the large amount of charge now...
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.
How it works:
Using a mercury source, we have at our disposal three very bright visible lines, in the blue, green and yellow (doublet), and a rich selection of ultra-violet. Our main source is a Phillips Lifeguard 1000W street lamp with its outer (uv...
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