Double Slit Interference

Helium-Neon Laser

Atomic spectra

To solve the puzzle of the atomic structure, we must study the atomic emission spectraWhite light is not actually white – it consists of many different colors. The composition of light – its spectrum – is studied by a device called a spectrometer

Diffraction grating

When there is a need to separate light of different wavelengths with high resolution, then a diffraction grating is most often the tool of choice. This "super Prism" aspect of the diffraction grating leads to application for measuring Atomic Spectra in both laboratory instruments and telescopes.

Refraction

Prism

Rutherford's atom

Rutherford's atom: 
Experiment:

He beamed alpha particles through gold foil and detected them on a screen

Discovery of cathode rays

Discovery of cathode rays

Discharge tube experiments:

Structure:

1.A cylindrical glass tube about 50 cm long, closed at both ends called the discharge tube

2.The tube is fitted with two metallic electrodes, which are connected to a source of high voltage

3.It is filled with gas and the discharge tube is connected to a side tube, through which the gas can be evacuated to any desired pressure with the help of a vacuum pump

Structure of Atom

Greek philosopher:

All matter can be divided into smaller parts
Each part can be subdivided into smaller parts and further into smaller one and so on until reaching undividable fragment called ATOM which means in Greek language (no divide)