Standard 1/Middle School/Benchmark
Benchmark Question: How does soil determine surface
changes over time?
Focus Question: What are the basic soil sample types
and what characteristics do they have?
The class will examine three
different types of sediments: sand, silt, and clay and compare grain size,
shape, and color.
The class will collect and
identify three very different types of soil samples by analyzing their
components and describing their qualities.
While collecting their
samples, students will need to list features of the environment — number of
trees, percent of ground cover, standing water, etc.
Students will place their
samples in jars with water, shake their jars, and observe them.
Students will record
observations of the layers of sediment and measure the depth of each layer.
Students will estimate the
percent of sand, silt, and/or clay in their soil samples. They will
classify their soil samples based on these estimates.
Students will apply their
gathered environmental data to hypothesize what surface changes can occur
at the soil sample site due to wind, water, and erosion.
Students will present their
findings and discuss their conclusions in written lab reports.
Note: This is a good activity related to
soil and surface change. Students may not be able to collect three
different types of sediments. Sandy, silty, and clayey soil (soil texture)
may not be found on one campus (or town). The teacher may need to get these
soils well ahead of time. Surface samples will have plenty of organic matter that will
cloud the water so much that it will be difficult to see the sediment.
Teachers should get soil samples that are relatively free of organic
Also, the number of trees, percent of ground
cover, standing water, etc. are not likely to be distinguished by soil type
on a campus as a function of texture because other factors (perched water
table, amount of humus, presence of surface impermeable surface) can mask
the effect of soil textures.