Soil texture is a classification instrument used by geologists both in the field and laboratory to determine soil classes based on their physical texture. Soil texture can be determined using qualitative methods such as texture by feel, and quantitative methods such as the hydrometer method. Soil texture focuses on the particles that are less than two millimeters in diameter which include sand, silt, and clay. Soil classifications are based on the percentages of sand, silt, and clay in the soil.
Determining soil texture is often aided with the use of a soil texture triangle. The Soil texture triangle image below shows the major textural classes.
Sand is a granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass.
The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. The second most common type of sand is calcium carbonate, for example, aragonite, which has mostly been created, over the past half billion years, by various forms of life, like coral and shellfish.
At the cache site you should collect a sample of the soil. You then need to conduct an experiment to check the condition of the soil. You can do the experiment at the cache site or you can take the soil sample home and test there. Please provide the cache owner with answers to the questions listed after the experiment description.
Place your soil sample in a clear container at least 120ml in size. Half filled with soil is about right. Fill the container with clean water. Shake. Shake that thing. Sit the sample down and allow the container to rest for at least 15 minutes. The layers you see are sand, silt, and clay in the soil sample. The bottom layer is sand. The middle layer is silt. The top layer is clay. The clay may take all day to settle. Organic matter will float. Ignore this material.
-Can you see layers in the settled sample? Estimate the percentage of each layer.
-Based on your experiment what is the soil classification at the listed location using the chart?
-What was the colour and texture of the soil sample?