Personal life

Air Pressure The weight of the air above Earth?s surface Thanks to gravity, the atmosphere has weight. What affects air pressure? Altitude ? air pressure decreases the higher you go up 2 miles up Sea level Decreasing Air Pressure Higher Concentration of air molecules Gravity forces most air molecules to remain close to Earth?s surface Cold air is more dense than warm air Cold air has higher air pressure because the molecules are closer together v v COLD HOT Warm air has LESS air pressure because molecules are farther apart COLD HOT Which air mass can hold more water vapor? v v COLD HOT v v c COLD HOT Air Molecule Water Molecule Warmer air can hold more water molecules than cooler air

What about clouds? What are clouds? Large masses of millions of water droplets suspended in air Water evaporates from lakes, streams, and oceans and enters into the air Transpiration ? the loss of water from plants through their leaves Evapotranspiration ? combines evaporation and transpiration Example of Transpiration: Cloud Forest Steps involved in cloud formation: ?..Warm, MOIST air RISES ?.a drop in air pressure causes?.. ?.Expansion and the air Cools .... Water vapor then?.. ??..Condenses on?? ?..Condensation Nuclei (a surface upon which condensation droplets can stick on. Ex: dirt, salt, smoke) ??..Clouds form!!! Condensation Nuclei Size comparison between raindrop and condensation nuclei Cirrus clouds ? High altitude clouds Cumulus Clouds

WHY DO PEOPLE MIGRATE? Push Factors Why people want to leave a place. Their lives might be in danger (war, famine) There may be limited economic opportunity Family members may have died or moved Pull Factors Why people are attracted to a new place. The new place might be more secure There may be more available jobs Relatives or friends may be there already REASONS FOR THE BANTU MIGRATION The reasons for the migration of the Bantu are not known but most likely included the following: Drought and famine: The Bantu moved to escape famine, which was a result of overcrowding and drought. The climate in their cradle land had become unreliable/unpredictable.