Sapna was making an orange flavoured drink. She poured 3-4 teaspoons of concentrated orange juice into a glass. She then added water until the glass was full and stirred it slowly.

(a) Explain how the orange juice spread into water.

(b) What is the effect of stirring?

(c) What is this intermixing of particles called? Name the type of substances which show this phenomenon the fastest.

(d) "There is no more movement in the liquid in the glass once the orange colour of the juice has stopped spreading."

Is this statement correct? Justify your answer.

(a) The particles of orange juice and water are constantly moving. Due to this random motion, the orange juice particles mix and spread throughout the water.

(b) Stirring increases the speed of mixing. It helps the orange juice particles spread faster in water.

(c) The intermixing of particles is called diffusion. Gases show diffusion the fastest.

(d) The statement is incorrect. Even when the orange colour stops spreading, the particles in the liquid are still moving continuously. The movement becomes uniform in all directions, so no visible change is seen.