False-colour scanning electron micrograph of standard filter paper clogged with silt particles after soil-contaminated water was passed through it. Filter paper is used to separate the liquid from the solid parts of a suspension. It is made from wood pulp (in particular that obtained from spruce,poplar,pine and fir trees),hence the presence of the cellulose fibres seen here under the silt. Soil contains gravel,sand,silt & clay. Most of the particles here are silt,with a size range of 2 to 50 micrometres. Gravel & sand would be unlikely to stay suspended in water anyway,while,at this magnification,the clay is probably invisible. Magnification: x60 at 6x4.5cm size |