• What are the world’s largest bodies of ice?
  The largest bodies of ice are the ice sheets of Antarctica and ...

• What is an ice age?
  During ice ages, average temperatures fall and ice sheets spread over ...

• When did the last ice age take place?
  The last ice age began about two million years ago and ended 10,000 ...

• What are wadis?
  Wadis are dry waterways in deserts. Travellers sometimes shelter in ...

• Can water change desert scenery?
  Thousands of years ago, many deserts were rainy areas and many land ...

• Where do rivers start?
  Some rivers start at springs, where ground water reaches the surface. ...

• Why do waterfalls occur?
  Waterfalls occur when rivers cross hard rocks. When softer rocks ...

• What are tributary rivers?
  Tributary rivers are rivers that flow into a main river. This swells ...

• How do you date fossils?
  Sometimes, dead creatures are found buried under volcanic ash. The ...

• What are deltas?
  Deltas are areas of sediments -made up of sand, mud and silt - that ...