water cycle

• The water cycle


  1. Energy from the sun makes water evaporate from the land and sea

  2. Water also evaporates in plants (transpiration)

  3. The warm water vapour is carried upwards

  4. It cools and condenses to form clouds

  5. Water falls from the clouds as precipitation onto land

  6. Some water is absorbed by the soil and taken up by plant roots

  7. Some water taken up by plants becomes part of the plants' tissues and is passed along to animals in food chains

  8. Water that doesn't get absorbed by the soil will runoff into streams and rivers

  9. The water drains back to the sea, before it evaporates all over again
• The carbon cycle


  1. CO2 is removed from the atmosphere by green plants and algae through photosynthesis

  2. When the plants and algae respire, some carbon is returned to the atmosphere as carbon dioxide

  3. When the plants and algae are eaten by animals, some carbon becomes part of the fats and proteins in their bodies

  4. When the animals respire, some carbon is returned to the atmosphere as CO2

  5. When plants, algae and animals die, other animals and microorganisms feed on their remains and respire, returning CO2 to the atmosphere

  6. The combustion of wood and fossil fuels also releases CO2 back into the air
• Global warming


  • The temperature of the Earth is a balance between the energy it gets from the sun and the energy it radiates back out into space
  • Gases in the atmosphere act as an insulating layer, absorbing and re-radiating energy, increasing the temperature of the planet
• There are several greenhouse gases which help keep the energy in
• The Earth is gradually heating up due to the increasing levels of greenhouse gases - this is called global warming
• Global warming is a type of climate change and causes other types of climate change
• Higher temperatures


  Causes seawater to expand and ice to melt, causing sea levels to rise, leading to flooding and loss of habitats