Soil, Rocks and Color

• Rocks are our world– Third rock from the Sun– Solid mineral deposits

• Soil is unconsolidated mineral matter– Influenced by decayed matter & environment

• Color is an important property of rocks & soil

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Rocks and Minerals

• Old rocks, new rocks and rocks of all ages in between– 3 billion years to less than 1 million years

• Continuous process called the rock cycle

• Three rock types Igneous

sedimentary Metamorphic

rock cycle rock types

Rocks are composed of one or more minerals

– Rock Salt - 1 mineral, halite (NaCl)

– Granite - Several minerals including: feldspar, quartz & mica

Rocks Website Rock Identification

Soil is much more than “dirt”

• Critical to life• How much soil is there?

Color of Rocks and Soil

• Early artists used natural pigments from rocks and soil (earth tones)– Mostly from iron oxides– Umber, sienna, ochre

• Color used in classification to asses– Physical properties– Mineral content– Chemical contentAncient Oil Painting From Pisa

Color of Soil

• Moisture level affects brightness– Typically moist soil is darker; dry is

brighter

• Soil temperature is affected by color– Black soil absorbs more solar radiation

• Warms up earlier in the spring for germinating seeds

• On a hot day in summertime, temperature can exceed 50 degrees C

Lab Activity

• We will investigate the possibility of using the ALTA II reflectance spectrometer to distinguish different rocks and soils

• We will investigate the possibility of using the ALTA II to determine soil moisture content.

Activity #1

Activity #2