• Earth - our home - is a unique and beautiful entity.  It is also a complex entity because it is not static.

• It is a dynamic place with many interacting parts that form a complex and continuously interacting whole - "Earth System".

• A change in one part of the Earth System can produce changes in one or any of all of the other parts.

A. Weather and Climate
 

• Weather (definition) - the state of the atmosphere at any given time; a short period of time.

• Climate (definition) - a description of aggregate weather conditions; the sum of all statistical weather information that helps describe a place or region; it also includes the extremes.

B. Earth’s Subsystems (Spheres)
 

• Biotic - living; Abiotic - nonliving; all four spheres are interconnected

• Atmosphere - a thin layer of gases (below 480 km) surrounding the Earth, and held to the Earth by gravity; it forms a protective boundary between outer space and the biosphere
• Hydrosphere - an abiotic open system that includes all of the Earth’s waters (surface, atmosphere, & crustal; & gaseous, solid, & liquid)
• Lithosphere - the Earth’s crust and that portion of the upper mantle directly below the crust that extends downward to 70 kilometers (km) (45 miles)
• Biosphere (ecosphere) - that area where the atmosphere, hydrosphere, and lithosphere function together to form the context within which life exists.

• it is an interconnected web that links all organisms with their physical environment
• just as the other three spheres impact and shape life, life itself impacts and shapes the other three spheres

(1) Weather/Climatic Elements/Variables:

• air temperature
• humidity
• cloud cover - type & amount
• precipitation - type & amount
• atmospheric pressure
• wind - speed and direction

• Mass .... SI unit is the kilogram (kg)

• Length .... SI unit is the meter (m)

            (1 km = .621 miles)

• Time .... SI unit is the second (s)
• Temperature SI unit is the Kelvin (K)

• a quantity that tells us how hot or cold something is relative to some standard value
• a measure of the average kinetic energy of the air molecules
• a measure of the average speed of the atoms and molecules that comprise air. (Higher temps correspond to faster average speeds.)

Fahrenheit (⁰F)     32 F = freezing point of water

            212 F = boiling pt. of water
 
 

Celsius (⁰C)     zero C = freezing pt. of water

            100 C = boiling pt. of water
 

Kelvin Scale (Absolute scale)
 

        0 K = coldest possible temp = no molecular motion

        273 K = freezing pt. of water = 0 Celsius =32 F

        373 K = boiling pt of water = 100 Celsius = 212 F
 
 

                        ** 1 degree of Celsius = 1 Kelvin * *
 
 

Temperature Conversions:
 

        C = K - 273, K = C + 273

        C = 5/9(F - 32); F = 9/5C + 32
 
 

• mass, length, time, and temperature are "scalar quantities" - they are specified only by a "magnitude"
• Vector quantities: are specified by magnitude and direction

• Speed - change in distance/change in time

           Examples: miles/hour; meters/secs; km/hr
 

            1knot = 1 nautical mile/hour = 1.15 statute mi/hr; 1 m/s = 2.24 mi/hr
 
 

• Velocity (v) - speed in a given direction

• Acceleration (a): change of velocity in time

• Force (F): mass times acceleration

Note: weight (w) is actually a force. It’s a measure of the force exerted by a mass under the acceleration of gravity (g).
 
 

        w = m x g (g = 9.8 ms^-2)

        (near Earth’s surface, 1 Netwon=.2248lbs)
 
 

• Energy: the ability to do work (types: kinetic, potential, radiant, chemical, electric, and magnetic).

• Pressure (p): force per unit area (F/A)

        1 inch of mercury = 33.86 mb

        average atmospheric pressure at sea level = 1013.25 mb = 1 std. atmosphere

        =29.92 in mercury (Hg) =14.7 pounds/square inch (psi)
 
 

        Sea Level Pressure
 

        1084 mb - highest ever recorded (Agata, Siberia Dec. 31, 1968)

        1050 mb - a strong high

        970 mb - a strong low

        870 mb - lowest press. ever recorded (Typhoon, Pacific Ocean, Oct. 12, 1979)
 

D. Conversion of Units
 

• It is often necessary to convert from one system of units to another or from one unit to another of the same type but of different size.

• Say, for example, we wish to convert 8 feet to its equivlent value in inches. We need to use a conversion factor - which has a value of 1.

• Consider the fraction 12in/1ft. The numerator and denominator are equal, so the value of the fraction is 1. Thus, we can multiply by this fraction without changing the physical length, but we do change the unit in which it is measured.

        8 ft X 12 in/1 ft = 96 inches (feet cancel)

• Let’s convert from 90km to its equivalent in meters:

• Let’s try another, 90 km to miles:

• One more, 35cm to inches: