(Most Important) Unit Conversions

(Most Important) Unit Conversions

• length
• area
• volume
• mass
• pressure
• energy
• power
• temperature
• radioactivity
• scientific notation

Length

• 1 (statute) mile (mi) = 1.6093 kilometer (km)
• 1 (nautical) mile (mi) = 1.8520 kilometer (km)
• 1 foot (ft) = 0.3048 meter (m)
• 1 yard = 0.9144 meter (m)
• 1 inch (in) = 2.54 centimeter (cm)
• 1 angstrom (A) = 10-8 centimeter (cm) = 10-10 meter (m)

Area

• 1 square kilometer (km2) = 106 square meters (m2) = 100 hectares (ha)
• 1 hectare (ha) = 10,000 square meters (m2)
• 1 acre (ac) = 4047 square meters (m2) = 0.4047 hectare (ha)

Volume

• 1 milliliter (ml) = 1 cubic centimeter (cm3)
• 1 cubic meter (m3) = 1000 liters (L)
• 1 (US) quart (qt) = 0.9461 liter (L)
• 1 (US) gallon (gal) = 3.7854 liter (L)
• 1 (US) pint = 0.4723 liter (L)
• 1 (US) fluid ounce = 29.6 milliliter (ml)

Mass

• 1 metric ton (m.t.) = 1000 kilograms (kg)
• 1 pound (lb) = 0.4535924 kilogram (kg)
• 1 ounce (oz) = 28.3495 grams (g)

Pressure

• 1 pascal (Pa) = 1 newton/square meter (N/m2) = 1 Kg m-1 s-2
• 1 bar = 0.98692 atmosphere (atm) = 105 pascals (Pa)
• 1 pound per square inch (psi) = 68.97 millibars (mb) = 6897 pascals (Pa)

Energy

• 1 joule (J) = 1 newton meter (Nm)
• 1 calorie (cal) = 4.184 joule (J)
• 1 kilowatt hour (kWh) = 3.6 x 106 joules (J) = 8.60 x 105 calories

Power (energy per unit time)

• 1 watt (W) = 1 joule per second (J/s) = 14.34 calories per minute (cal/min)

Temperature

• from Fahrenheit to Celsius: C = (F - 32) x 5/9
• from Celsius to Fahrenheit: F = (C x 9/5) + 32
• from Celsius to Kelvin: K = C + 273.15

Radioactivity

• 1 Curie (Ci) = 3.7x1010 Becquerel (Bq)
• 1 Gray (Gy) = 1 J/kg tissue = 100 rad

Commonly used prefixes...

Scientific notation

Prefix...........	Exponent	Examples of exponential usage:
peta (P)	15	amount of CO2 in atmosphere (as C)- 750 Pg (or Gt)
tera (T)	12
giga (G)	9	pool sizes: amount of water in ocean - 1.37 x 109 km3
mega (M)	6	rates: flow of Anatarctic Circumpolar Current - 200 x 106 m s-1
kilo (k)	3	distance New York - Albany ~ 350km
hecto (h)	2	atmospheric pressure: ~1012.5 hPa (=1012.5 mbar)
base unit	0
milli (m)	-3	typical amount of medicine ~1ml
micro (m)	-6
nano (n)	-9	wavelength of violet light ~400nm
pico (p)	-12	size of atom ~10pm
femto (f)	-15	detection limit of gas chromatographs for SF6 : ~1 fmole/L