Scientific Measurements:

Objectives:

    1.    Compare the different units of measurement in the metric system.

    2.    Explain how to measure distance, volume, mass, & temperature in standard metric measurements.

    3.    Demonstrate how to measure the metric units distance, volume, mass, & temperature.

Key Terms:

    

Web Resources:

    www.unc.edu/~rowlett/units/

    www.physics.nist.gov/cuu/Units/background.html

    Units of Measurements and Uncertainty:

Notes:

Metric prefixes    English to metric conversions    SI values    Common measurements is science

Throughout the different scientific disciplines you will find the use of the metric system.  Becoming familiar with the standard prefixes will make solving equations and converting units easier.

Prefix Symbol Meaning Scientific Notation
exa- E 1,000,000,000,000,000,000 1018
peta- P 1,000,000,000,000,000 1015
tera- T 1,000,000,000,000 1012
giga- G 1,000,000,000 109
mega- M 1,000,000 106
kilo- k 1,000 103
hecto- h 100 102
deka- da 10 101
meter   1 100
deci- d 0.1 10-1
centi- c 0.01 10-2
milli- m 0.001 10-3
micro- m 0.000001 10-6
nano- n 0.000000001 10-9
pico- p 0.000000000001 10-12
femto- f 0.000000000000001 10-15
atto- a 0.000000000000000001 10-18

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English to Metric Conversions:


Distance Mass Volume Pressure / Energy Temperature
1km = 0.62 mi 1kg = 2.2lbs 3.744L = 1 gal 101,325Pa = 1atm oC = 5/9 (oF-32)
1m = 39.37in 907.185kg = 1ton 1 L = 1.06qt 4.184J = 1cal oK = oC + 273
1m = 1.0963yd 28.3g = 1oz 250ml = 1c    
1cm = 0.39370in 453.59g = 1lb      

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The units used in science are those primarily used throughout the world.  The International System of Units (SI) is a system based on the metric system.  There are 7 fundamental units of measure. 

Name Symbol Unit of Measure Unit Symbol Unit Dimensions
length (distance) l (d) meter m m
mass m kilogram kg kg
time t second s s
electric charge Q coulomb C C
temperature T Kelvin K K
amount of a substance n mole mol mol
luminosity intensity l candela cd cd

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All other SI units can be derived from the above 7.

Name Symbol Unit of Measure Unit Symbol Unit Dimensions
acceleration a meter per second squared m/s2 m/s2
area A square meter m2 m2
capacitance C Farad F C2*s2/kg*m2
density D kilogram per cubic meter kg/m3 kg/m3
electric current I Ampere A C/s
electric field intensity E Newton per coulomb N/C kg*m/C*s2
electric resistance R Ohm d kg*m2/C2*s
emf x Volt V kg*m2/C*s2
energy E Joule J kg*m2/s2
force F Newton N kg*m/s2
frequency f hertz Hz s-1
heat Q Joule J kg*m2/s2
illuminance E lumens per square meter lx cd/m2
inductance L Henry H kg*m2/C2
luminous flux F lumen lm cd
magnetic flux f Weber Wb kg*m2/C*s
magnetic flux density B Tesla (weber per square meter) T kg/C*s
potential difference V Volt V kg*m2/C*s2
power P Watt W kg*m2/s3
pressure p Pascal (Newton per square meter) Pa kg/m*s2
velocity v meters per second m/s m/s
volume V cubic meter m3 m3
work W Joule J kg*m2/s2

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Some commonly used values in science.

Speed of light in a vacuum 2.9979 x 108 m/s
Speed of sound 330 - 350 m/s (depending on temperature)
Acceleration due to Gravity 9.8 m/s2
Average Earth - Sun distance (1 AU) 1.50 x 1011 m
Average Earth - moon distance 3.84 x 108 m
Average radius of the Sun 6.96 x 108 m
Average radius of Jupiter 6.99 x 107 m
Average radius of Earth 6.37 x 106 m
Average radius of the moon 1.74 x 106 m
Average radius of the hydrogen atom ~5 x 10-11 m
Mass of the Sun 1.99 x 1030 kg
Mass of Jupiter 1.90 x 1027 kg
Mass of Earth 5.98 x 1024 kg
Mass of the moon 7.35 x 1022 kg
Proton mass 1.6726 x 10-27 kg
Neutron mass 1.6749 x 10-27 kg
Electron mass 9.11 x 10-31 kg
Atomic mass unit (amu) 1.66054 x 10-27 kg
Electron charge 1.6 x 10-19 C
Avogadro's number 6.02 x 1023
Planck's constant (h) 6.6262 x 10-34 J-s
Gas constant (R) 0.08206 atm-L/mol-K 
Molar volume of gas 22.4L

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