Science Soil Index Cards (7th Grade)

Question	Answer
Soil	a mixture of weathered rock, humus (organic material), water and air that supports plant life
Soil Formation	Over time, weathered rock is broken down into soil particles
What are 5 factors that affect Soil Formation?	1) Parent Bedrock 2) Topography 3) Climate 4) Time 5) Organisms
Parent Bedrock	rocks weather differently (EX: Limestone weathers to clayey soil, sandstone weathers to sandy soil)
When you have bedrock that forms fast, soil will what?	Form faster
Topography	The slope of the land also determines the affect of soil formation. (EX: On a steep hillsides soil does not form, but on flat land, thick soil develops)
Climate	In moist hot climates, weathering occurs at a greater rate than cold, dry climate. In tropical climate, there would also be more organic matter to decay faster
Time	Weathering rocks takes thousands of years. Soil formation takes many years. Thicker soil forms in areas that have been undisturbed for many years
Organisms	Different organisms affect the soil formation in different ways. (EX: Lichens and alga, small plants and others, and animal activity can affect soil formation.)

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