For practice :  TWO EVENTS :
1. The  water of the lake which is polluted by garbage dumping evaporates at a higher temperature .
2. The pressure cooker helps the mountaineers to cook  the food
OBSERVATIONS:

• The evaporation of the water  is affected due to impurities which affects the vapor pressure of water
  
• The water boils at lower temperature by increasing the pressure over the water in the pressure cooker