With a selection of different soil types, analyse their components by sieving and a sedimentation in water.
The activities can be set up as two stations, which the students switch between.
This can be a messy activity - do it outdoors if you can.
The seiving sorts soil components by size and the sedimentation test sorts soil components by how well they float or sink in water.
Learn that there are a wide range of different soil types.
Beach soil is mostly rock particles.
Forest soil is mostly organic matter.
Garden soil is in the middle.
Discuss how each soil type was formed and how this determines its’ composition:
Forest soil is mostly made from the decomposition of dead plants by the decomposers (snails, worms, wood bugs). If relevant, refer back to a forest walk and the decomposers observed.
Beach soil is mostly composed of sand. This is made by the weathering of rocks, and is then carried by ocean currents before being deposited on the beach. The few plants that grow in the sand generate a thin soil as they die and decompose.
Garden soil is a mixture of rock (mineral) components and organic matter.
City soil (construction site fill) has very little organic components - it is mostly rock particles of different sizes.
Soil also contains water, air and living things.
Good soil info at: https://www.nature.com/scitable/knowledge/library/what-are-soils-676476…