The fine clay particles will finally settle, but it may take a day or so. Organic matter may remain floating around on the top. Looking at the layers, you can now see, comparatively, just how much sand, silt and clay make up your soil. If the clay layer makes up half or more of your sample, you have a heavy clay soil. Soil that is equal parts of clay, silt and sand is called loam.
Sandy soils have very little clay.
The best way to do a percolation test is to dig a hole about 2 feet deep and a foot wide. Fill that hole with water and let it drain completely. Now fill it again and keep track of how long it takes to drain. If it drains in less than 12 hours, the soil should be able to support plants that require well-drained soil. If it takes 12-24 hours to drain, the soil is best suited to plants that tolerate heavy or clay soils.