To show the impact of a raindrop on soil
Place a saucer or jar lid filled with soil on a piece of white paper. Fill a medicine dropper with water and hold it about a metre above the soil. Release water a drop at a time and get how much soil is splashed out on the paper. Place a clean sheet of paper under the saucer. Again free drops but hold an obstacle like as a pencil in the path of the drop to break the force of the raindrop. Do plants stop the wearing away of the soil in this way?