AIM
To observe the effect that different gas pressures have on an electric discharge passed through a discharge tube.
BACKGROUND INFORMATION
The high voltage produced by the induction coil is applied across the terminals inside the discharge tubes. One plate (the cathode) becomes highly negative and releases a ray (cathode ray or electron). The electron passes through the gas in the tube and excites electrons in the atoms of the gas contained in the tube. The pressure of the gas determines the density of the atoms and therefore the nature of the collisions which take place between the electrons and atoms. Therefore, different discharge effects under different pressures can be observed.