Unit 3: Weather and Climate Ms. Thind

Where does water vapour take place? - rivers, lakes, oceans, soil, plants Evaporation that takes place at plants? - transpiration What is precipitation? - water in any state that falls on earth Where is this rain produced? - Clouds What type of clouds? - mostly nimbus clouds Different types of precipitation? - rain, snow, sleet, hail, frost,….

(1) Snow: * temperature of the air in which condensation is occurring is below 0°C * Ice crystals formed are 6 sided * Dry snow: condensation does not occur until well below freezing point * Large/wet snow: condensation takes place just below freezing point

(2) Sleet * Mixture of snow and rain * Occurs when condensation takes place near freezing point (3) Hail * Freezing of water droplets when upward air currents carry the drop of water into cold regions

* Evaporation of water from bodies of water and plants  evapotranspiration * The amount of water vapour in the air is called humidity * The actual amount of water vapour in a given volume of air is called absolute humidity * Relative humidity expressed as a % of the amount of water vapour in the air compared to the max. of water vapour the air could hold

* Important for weather forecasts because it is an indicator for the likeliness of precipitation, dew or fog. * High humidity: air is moist * Low humidity: air is dry * Temperature at which air becomes saturated is called dew point