geo

• Water


  An important resource
• Reasons why water is an important resource

  • Human beings need water to survive
  • Life on earth depends on water (flora & fauna)
  • Plants provide us with oxygen to breathe
  • Water is necessary to grow food (both crops & livestock)
• Why do we study this topic?

  • Water is an important resource
  • A resource is anything we use to satisfy our needs and wants
  • Water is an environmental resource (because we get it from the natural world)
  • All life on Earth depends on environmental resources like water
  • As our population grows, we place more and more pressure on these resources
  • Not everyone has the same access to resources like water
• Types of environmental resources

  • Renewable resources
  • Non-renewable resources
  • Continuous resources
• Examples of environmental resources


  • Renewable: Trees in a forest, Fresh water
  • Non-renewable: Coal, Oil
  • Continuous: Energy from the sun, Energy from wind
• Fresh water is considered a renewable resource however it needs to be carefully managed
• Water is a renewable resource

  • The amount of water on earth has not changed since the beginning of time
  • The water used by ancient and extinct animals and plants millions of years ago is the same water that falls today as rain
  • The amount of water on earth cannot be increased or decreased. It is cycled and recycled (by the water cycle), and constantly changes its state/form
• The three forms (or states) of water

  • Gas: such as fog and evaporation
  • Liquid: such as water in a river or the ocean
  • Solid: such as ice in a glacier
• Liquid water is constantly being recycled through the atmosphere, rivers and oceans in a natural system known as the water cycle
• Where is the world's water?

  • How much of the world's water is fresh water, available for our use?
  • What percentage of fresh water on earth is: Liquid (not ice)?, Surface water?, Groundwater?
  • Where is the 0.4% of water that is freshwater surface water stored?
• Although the surface of the Earth is covered with water, only a tiny percentage of that water is fresh and available for consumption
• As the population grows, the demand for water will increase. This will put increased pressure on Earth's finite water resources. The earth cannot produce more water for more people - the amount of water is finite.
• Groundwater


  Located within the earth's surface. It begins as rain water and filters its way through the earth's layers until it becomes trapped under the earth (in aquifers). It is drawn up to the surface naturally as spring water or by humans through bores and pumps.
• Frozen Water


  Much of the earth's fresh water is frozen in the ice caps and glaciers in mountains. This water may enter the rivers as glaciers melt, and this can increase the drinking water supply. If the ice caps were to completely melt there would be a rise in the level of the ocean of 60 meters. Some scientists have suggested that towing icebergs to countries with no water could produce a source of drinking water.
• Water


  An essential and renewable resource that occurs naturally on Earth
• Water is one of our most precious environmental resources. Without it, nothing can survive
• Water can exist as a solid (such as ice in a glacier), liquid (such as water in a river), or gas (such as fog)
• Fresh water


  An available resource when in liquid form and a potential resource as a gas or a solid
• Water cycle


  A natural system where water is constantly being recycled through the atmosphere, rivers and oceans
• Water may change form, but it never disappears. For this reason, the water cycle is considered to be a 'closed system'
• The water cycle is a good video for consolidating understanding and may also be a good revision tool
• Evaporation


  1. Energy from the sun heats the water

  2. Liquid water turns into water vapour

  3. Evaporation takes place all over the earth, but especially in the oceans and lakes
• Condensation


  1. Water vapour rises and cools

  2. Water vapour condenses into water droplets or ice crystals

  3. Water droplets or ice crystals form clouds
• Precipitation


  1. Water droplets or ice crystals become too heavy and precipitate as rain or snow

  2. Sometimes, the rain freezes before it hits the earth and precipitates as hail
• Runoff


  1. Precipitation gathers into rivers and streams that flow down to the lakes and oceans

  2. Not all of the water makes it back to the oceans and lakes right away, some is used by animals and plants, some is frozen into glaciers
• Eventually, the animals and plants breathe the water out and the glaciers melt, releasing the water back into the water cycle
• Types of rainfall


  • Orographic
  • Frontal
  • Convectional
• For all three types of rainfall, there is a mass of moist air that is forced to rise
• The Great Dividing Range in Australia has a significant impact on rainfall due to the rain shadow effect
• Rain shadow effect


  An area having relatively little precipitation due to the effect of a topographic barrier, especially a mountain range, that causes the prevailing winds to lose their moisture on the windward side, causing the leeward side to be dry
• Fresh water is essential for life on earth
• Most of the water on earth is NOT fresh water that is accessible for human use
• The water cycle is the natural process that 'recycles' water to replenish fresh water sources
• Fresh water is not equally distributed across the planet
• Some areas of the world have more water than they need, while other areas do not have enough water
• Water rich


  Countries with large rivers (such as the Amazon River in Brazil) and those with high rainfall (e.g. Indonesia)
• Water poor


  Countries (including Australia) that do not have enough water
• This map shows the proportion of the world's freshwater resources found in each country
• Countries that appear fat on the map are water rich, countries that appear thin are water poor
• Latitude lines are the imaginary lines that run horizontally around the world