1. Looking at rivers and maps

2. A map of all the rivers in Britain
Zoom in to the River Thames catchment area
Grayshott

3. Look at the rivers in the area around Grayshott
Why do the rivers wiggle and wander??
Grayshott
Let’s draw in the hills and see

4. Hills are shown on a map using contour lines
each contour line is drawn to show the same height on a hill, so as the lines are drawn, it starts to show the shape of hills and valleys

5. … and if we just look at the contours, we can start to see the shape of the land
but you need to know which bit is UP and which is DOWN

6. So if we put the rivers back …
rivers are always going downhill, so you can see which are valleys and which are hills
Topology maps are coloured to help, with pale green for lower areas, rising though shades of red/brown to show the hilly bits

7. Topology maps are coloured to help, with pale green for lower areas, rising though shades of red/brown to show the hilly bits
Now let’s see if you can make a map something like this in the sandbox, and see how the hills and valleys are shown, and how the water flows to make rivers