Elements: pure substance, monatomic or sometimes homoatomic. Mixtures: can vary in composition and properties, components can be physically separated. Iron metal and sand can be separated with a magnet. Take base unit of something and establish relationship centimeter= 1/100 of meter kilometer= 1000 meters. Meters are gonna cancel out and you multiply across. Commonly used metric units: length meter volume cubic decimeter, cubic centimeter (cc), liter mass gram, kilogram temperature degree celsius, kelvin energy joules, second. 1 decimeter= 10 centimeter (1 cm) (1 cm) (1 cm) (10 dm) (10 dm) (10 dm) = 1000 dm^3. A celsius degree is about twice as big as fahrenheit. You also have to shift by 32 degrees. When you add 32, you have to already be in fahrenheit. The kelvin scale isn"t positive or negative (not relative to anything) To go between celsius kelvin, just add or subtract 273. Problem: 98. 6 fahrenheit is considered normal body temperature.