Question

Describe an activity to show the effect of low pressure and particulate nuclei over water vapours?

Answer 1

Pour 5-10 mL of water into an empty mineral water bottle. Close the bottle rigidly. Shake the bottle well or keep it in sun for about 10 minutes. This causes evaporation of a major part of water so that the bottle becomes saturated with water vapors. Take lighted incense stick. Open the cap of the bottle and introduce some smoke of incense stick into it. Quickly replace the cap tightly.' Press the bottle between your hands and then release the pressure. Repeat the process 2-3times. Entry of smoke from incense stick makes the air foggy inside the bottle. The smoke particles function as nuclei and cause condensation of water vapors over them just as what happens during cloud formation. These water droplets appear on the sides of the bottle which come to have low pressure when pressure is released from the bottle. It is just like raining in response to low pressure.