What you need
Section of drainpipe
What you do
Place the drainpipe on the surface of the soil or land. Insert the ruler into the drainpipe so that it is standing on the soil surface. Pour a predetermined amount of water into the drainpipe. Time how long it takes for the water to infiltrate, or measure how much water remains in the drainpipe after a given length of time.
When you use it
Compare infiltration rates between different land uses: soils, grassland, woodland, agricultural land, footpaths, tarmac. Use in a study of footpath erosion or trampling (the water will not infiltrate into saturated ground) or in an investigation into the role of man made surfaces in increasing the risk of flooding in urban areas.