Demonstration Observations/conclusions

Front 1

To show that light is a wave

Back 1

• A pattern is found on it as shown.

• The pattern can only be explained if light is a wave, which diffracts at each of the two slits, and creates an interference pattern as the resulting waves meet.

• As diffraction and interference are wave characteristics, this demonstrates that light is a wave

Front 2

To show that sound is a wave

Back 2

• Walking along the dotted line shown in the diagram, we would hear the sound repetitively grow and fall in volume.

• This can only be explained if the sound is creating an interference pattern, thus demonstrating that it is a wave

Front 3

To demonstrate atmospheric pressure

Back 3

• The can slowly becomes crushed as it cools.

• This demonstrates the effect of atmospheric pressure, which is acting on the outside of the can, but is no longer balanced by an equal pressure from within

Front 4

To demonstrate Archimedes Principle

Back 4

• When the mass is lowered into the water, the reading on the spring balance is reduced by 'W' Newtons.

• This is the upwards force experienced by the mass.

• The weight of the displaced water will also be equal to 'W', indicating that an object immersed in a fluid will experience an upthrust equal in magnitude to the weight of the fluid displaced

Front 5

To find the resultant of vectors

Back 5

According to Newtons third law, the bottom meter should be equal in magnitude but opposite in direction to the resultant of the two upper meters

Front 6

Using the ice and steam points to calibrate a thermometer

Back 6

Divide the length between the marks on the thermometer into 100 even units, each representing 1°C. Or graph the results

Front 7

To demonstrate an electric field

Back 7

The semolina particles become slightly charged at each end, and line up along the lines of force, showing the shape of the electric field

Front 8

To demonstrate that a capacitor stores energy

Back 8

The bulb flashes. The presence of light energy indicates that energy had been stored on the capacitor

Front 9

To demonstrate the factors on which the capacitance of a capacitor depend

Back 9

When the plates are drawn apart, the leaves collapse, indicating that the stored charge, and therefore the capacitance, is inversely proportional to 'd'. Similarly we can show that reducing 'A', the common area, reduces the capacitance, and varying the material between the plates affects the capacitance.

Front 10

To show the distribution of charge on an object

Back 10

The charge is evenly distributed over the dome

Front 11

To Demonstrate that a current-carrying conductor in a magnetic field experiences a force

Back 11

When the current flows, the strip of foil moves, indicating that a current carrying conductor in a magnetic field experiences a force. The direction of the force can be determined by the left hand rule, and its magnitude is given by the formula

Front 12

To demonstrate the principal on which the definition of the Ampere is based

Back 12

The wires move apart, indicating that parallel wires conducting a current will experience a force, the principal on which the definition of the Ampere is based

Front 13

To demonstrate Electromagnetic induction

Back 13

When the magnet is moving, a current is shown on the galvonometer, indicating that the changing magnetic field is creating an emf as stated in Faraday's Law. The faster the magnet moves, the greater the current

Front 14

To demonstrate Lenz's Law

Back 14

The loop always moves in the same direction of the magnet, indicating that a current is flowing in the loop which opposes the change, as stated in Lenz's Law

Front 15

Rutherford's Gold Foil Experiment

Back 15

Most particles went through the foil. A small percentage was diverted through various angles as shown, while an even smaller percentage was repelled back towards the source. This experiment gave rise to the idea of the Rutherford-Bohr model of the atom, which is now the standard view of the atom. In this model:

• most of the atom is empty space

• there is a positively charged nucleus, which contains the protons and neutrons.

• the nucleus is surrounded by several 'shells' of negatively-charged electrons

Front 16

Cockroft-Walton

Back 16

2 alpha particles were created, as shown. After the reaction, they noted that some mass had 'disappeared', but energy had 'appeared'. It turned out that the loss in energy and gain in mass fitted perfectly with Einstein's equation: E=mc². This was the first experiment to verify Einstein's equation