Here is a fair test to see which kind of soil lets water through most easily. You need to look at the picture on the main screen as well.

Take three pots of the same size and fill them with the same amount of a sandy soil, a clay soil and a loam soil (mixture of sand and clay).

Pour the same amount of water quickly on to the top of each one.

When all of the water has nearly drained through one of the soils, take all collecting jugs quickly away and measure the amount of water. The more water in the jug, the faster the soil drains.