A student dissolves about 200 g of sodium thiosulphate (hypo) in about 2L of clean water

in the tank and adds about 1 to 2 mL conc. H2SO4 to the water. What would he observe

after the source of light S is switched on –

(i) from the three sides of the glass tank ?

(ii) from the fourth side of the glass tank facing the circular hole ?

You will find fine microscopic sulphur particles precipitating in about 2 to 3 minutes. As the sulphur particles begin to form, you can observe the blue light from the three sides of the glass tank. This is due to scattering of short wavelengths by minute colloidal sulphur particles. Observe the colour of the transmitted light from the fourth side of the glass tank facing the circular hole. It is interesting to observe at first the orange red colour and then bright crimson red colour on the screen.