Water Systems

Heat and temperature

• “hot” – lots of heat energy• “cool” – little heat energy• Something is cold if it will take away heat from

its surroundings

Heat Capacity

• The amount of heat energy that must be added to increase its temperature by 1 degree Celsius

Solvents

• Solvent – the liquid doing the dissolving• Solute – the substance being dissolved• Soution – the mixture of solvent with the

dissolved solute in it

What is salt?

• Any mix of acids and bases (an anti-acid)• Acids – lemon juice, coffee, vinegar, battery

acid• Base – baking soda, ammonia, soapy water,

bleach, drain cleaner• Table salt, Epsom salt, road salt, metal salts

that change the colour of fireworks, gunpowder

Salt water evaporation

• When water evaporates, dissolved minerals stay behind

• Water vapour is mostly pure water

If rainwater is fresh water, why are the oceans getting saltier?

• Dissolved rainwater weathers and erodes minerals as it runs down to the oceans and seas

• The minerals dissolve in the water

Hard and soft water

• Soft water has few minerals dissolved in it• Hard water is saturated with magnesium (Mg)

and calcium (Ca)• You want soft water running in your house– Doesn’t react well with soap = no suds or bubbles– Won’t build up deposits in your pipes

• People ‘soften’ their water with sodium salt, which kicks out the harsh Mg and Ca

Convection Cell

• What are the global sources of heat, and the global sources of cool

Ocean currents

• Lots of nutrients and oxygen comes from aquatic plants and decaying organic material– Get stirred up to surface by convection currents

• Cold water = nutrient rich water– Half of the world’s fisheries are supported by these

upwellings• Current is a movement in the water• Circular pattern of flow of ocean water called a gyre– A mix of several currents in different directions

Hot water meets air

• Hot water heats the air above it• Hot air contains more moisture• Hot air rises, cools in upper atmosphere, and

loses its moisture

High and low pressure

• Hot air rises – low pressure system– Usually comes with cloudy weather and

• Cold air sinks – high pressure system– Clear skies

• Air always moves from high to low pressure

Wind

• Sun shines on Earth, even heating of land and water, but different heat capacities– Means different temperature changes

Shortest distance between two points is…

• A Straight line

Why do flight paths look so curved

• Shorter distance at poles to travel• What about going straight north/south

Coriolis ‘Force’

• All things move in straight lines• Earth spins, makes objects moving in straight

lines appear to curve• **There is no force pushing winds or currents

in circles• Results in circular patterns to moving wind and

water – CW in the Northern hemisphere– CCW in the Southern hemisphere

Weather vs. Climate

• Weather is the present or day to day precipitation, wind, temperature, air pressure

• Climate is the long-term pattern in atmospheric pressure, temperature, humidity, wind, and precipitation

Ocean currents, wind, and climate

• Ocean currents moving away from Equator warm the air above them– More moisture/precipitation– Low pressure– Warmer air temperatures

• Winds blow this air over the land

What is a desert?

Desert formation

• Ocean currents moving away from the Poles are cold– Cool air over it, which then loses its moisture (as

fog usually)• When this dry air blows over land, sucks up

the moisture, creating dry climates• Dry, cold, descending air also creates dry, high

pressure climates

West coasts and ‘horse’ latitudes = deserts