Make your own fieldwork equipment: Gradient

What you need

• A water level/decorators level, available from DIY stores

• Two metre rules

• Tape

What you do

Attach the two cylinders to each end of the pipe and tape each cylinder to a meter rule so that the zero point of the ruler is at exactly the same place on the two cylinders. Fill the level with water so that it the pipe is full and water is visible in both cylinders. The water will naturally find its own level, so if the two meter sticks are on even ground the water in the cylinders will reach the same point on the meter stick. This equipment can be used to measure very slight differences in height between surfaces. For example, if the water level in one cylinder is 880mm and in the other cylinder it is 890mm, there is a 10mm difference in height between the two sites.

When you use it

Anywhere gradient measurements are required, for example sand dune or beach transects, river channel gradients, site levels. You can even use it to draw up contour maps of the school grounds. Gradient can be calculated using the following equation:

Horizontal gradient = Difference in height between sites ÷ Distance between sites