Let Us Create a River

  1. Making a model:
    • Place a couple of centimetres of moist sand on a wide board.
    • Place one side of the board on a brick or rock to create a slope.
    • Slowly pour water on the top of the tilted board.
  2. Observe the path of the water current through the sand:
    • What happens to the sand? (The water – river carries the sand away and makes itself a curved path.)
    • What do we call a process when water carries sand away? (Erosion)
    • What happens when we lean the board higher? (The process of erosion is stronger. The water current is faster.)
    • What is the shape of a river and what does the surrounding landscape look like when the flow of water is quick? (The water channel is more narrow and straight. The water current is faster.)
    • What happens if you lean the board lower? (The process of erosion is not that strong any more. The water current is slower.)
    • What happens with a water channel? (The water current is slow, and the water channel makes many curves and parallel channels.)
    • What happens within the curves? (Water takes away sand from the outer side of the curve and deposits it on the inner side of the curve. This is how meanders are formed and become larger.)
    • What is the shape of a river and what does the surrounding landscape look like when the flow of water is very slow? (The water channel is very wide and makes wide curves. The landscape is flat.)
    • What happens if you lean the board just a little bit in a perpendicular direction to the flow of the water? (The river creates a new path, which is the shortest according to the new conditions. The old river channel may dry out.)
  3. Learn new terminology:
    • Which word describes streams or small rivers that join a main river? (tributary)
    • What are the processes through which rivers shape a land called? (erosion, deposition)
    • What is the name of a lake that forms behind a dam? (reservoir)
    • What name is given to the mouth of a river as it nears a sea or ocean? (estuary)
    • What is a place where a river starts called (source, spring)
    • What is the name for the winding bends formed by rivers flowing through vast valleys and plains? (meander)
    • What are flat areas where mud is deposited called? (mudflats, floodplains)
    • What are the parts of a river where the flow of it is fast and in cascades called? (rapids)
    • Where do waterfalls form? (where a river flows from hard to soft rock)
  4. Make a model or a drawing of a river system from its springs in mountains, hills or other high grounds all the way to its discharge into a lake, lagoon or sea. Name all the elements in the drawing and discuss with other students what you have learned.