Presentations

Energy Stored in a Capacitor

What it shows:

The electrical energy stored in a capacitor is converted to mechanical work, driving a motor and raising a weight.

How it works:

A motor 1 is mounted atop a 2.5m length of 2×4. As it turns, it raises a 1 lb mass on a string from the ground by wrapping the string around a spindle (figure 1). The motor is driven by the discharge of a 12800µF, 75V capacitor previously charged by a DC power supply. 2 A double throw switch allows a clean change-over from one circuit to the other.… Read more about Energy Stored in a Capacitor

Para and Diamagnetism

What it shows: 

The behavior of a substance in a non-uniform magnetic field will depend upon whether it is ferromagnetic, paramagnetic or diamagnetic. Here we test different substances to see how they are influenced by a magnetic field.

How it works: 

We have a collection of samples (listed in table 1) that exhibit well the three magnetic properties. Diamagnetic substances have a negative relative permeability (susceptibility); paramagnetic substances have positive.

Ferromagnetic substances have permanently… Read more about Para and Diamagnetism

Wien's Displacement Law

Changes in the spectral intensity distribution of a hot tungsten filament are observed as the temperature is varied.

wien

How It Works

A slide projector (Beseler Slide King II) with a 1kW lamp and adjustable lens is plugged into a Variac. The light from the projector passes through an inline… Read more about Wien's Displacement Law

Neutron Activation of Silver

What it shows:

One of the more important discoveries in modern physics is the production of isotopes (both radioactive and stable) by the capture of neutrons. 1 In this experiment the bombardment of silver by thermalized neutrons produces short lived radioactive isotopes of silver whose half lives can readily be measured. It can also be shown that bombardment by fast neutrons does not induce radioactivity because of the extremely low neutron cross sections involved. Using a Geiger counter in conjunction with a multichannel analyzer in the MCS (… Read more about Neutron Activation of Silver

Lead Bell

Dull at room temperature, rings clearly after immersion in liquid nitrogen.

What it shows: 

A lead bell, dull sounding at room temperature, rings brightly when cooled to liquid nitrogen temperatures.

How it works: 

A lead bell at room temperature is dull in more ways than one. But its elasticity is temperature dependant, with an increase in elasticity as its temperature decreases. This increase in elastic modulus narrows the resonance response with frequency and increases the quality Q of the lead as an… Read more about Lead Bell

Smog in a Bottle

Nitrogen dioxide is produced by an electric discharge in air and, when sprayed with a water mist, produces acid rain.

What it shows:

Some of the most irritating and dangerous pollutants in our atmosphere are gases such as sulfur dioxide and nitrogen dioxide. Nitrogen dioxide is a deep orange-red gas that, together with smokelike particles, is responsible for the color of smog. In this demonstration, nitrogen dioxide is produced by an electric discharge in air and, when sprayed with a water mist, produces acid rain.

How it works:Read more about Smog in a Bottle

Loaded Beam

loaded beamsBeam supported at ends with platform scales and toy truck as load to demonstrate moment arms.

What it shows:

The concept of moment arms is exemplified by this model of a truck on a bridge.

How it works:

A beam (board) supported… Read more about Loaded Beam

Gravi Car

A falling weight propels a car forward.

What it shows:

Gravitational potential energy can be converted into mechanical kinetic energy.

gravi car

How it works:

A Gravicar is a vehicle powered by gravitational potential energy that it stores in a 2.5kg mass on a thread which is coupled… Read more about Gravi Car

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