Download Science 10 Unit D: Energy Flow in Global Systems2011 Unit D

Science 10
Unit D: Energy Flow in Global Systems2011
Unit D: Overview [p 339]
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Solar energy sustains life and drives the global climate systems on Earth.
Without solar energy there would be no heat or precipitation and therefore, no life on Earth.
The absorption and transfer of thermal energy at and near Earth’s surface results in a variety of
climate zones with characteristic weather patterns and biomes.
Climatic factors determine the flora and fauna found in each of the world’s major biomes.
Using a variety of techniques, scientists have concluded there is a relationship between human
activity and climate change – a change that could potentially harm the environment and our economy.
Section D 1.0 Climate Results from Interactions of the Components of the Biosphere
Reference p 342 - 355
What is a Global System?
- a system is objects, organisms, processes, machines or things that have some influence on one another.
systems can be made of subsystems (eg. your body, a refrigerator etc)
Three kinds of Systems:
Open - both matter and energy can cross the systems boundary (eg. plants)
Closed - energy can cross but not matter (eg. a closed flask, Earth ...)
Isolated - neither matter nor energy is exchanged with surroundings
Biosphere ("living globe") - a global system which interacts with energy from the Sun
 the thin layer of air, land and water on or near the Earth’s surface that contains all life
3 Divisions of the Biosphere interact with each other:
Lithosphere ‑ Earth's crust (continental & oceanic)
‑ soil (mixture of fine particles of rocks, minerals and decomposed organic materials) provides water and
minerals for plants. (Fig. D1.6)
Hydrosphere ‑ all Earth's saltwater, freshwater, aquifers and cryosphere (frozen water)
‑ covers over 70% of Earth's surface & constantly cycles in and out of the atmosphere
Atmosphere ‑ a thin layer of well mixed gases (nitrogen, oxygen, carbon dioxide and water vapour*)
surrounding Earth.
*may be considered part of hydrosphere
- main divisions troposphere, stratosphere, mesosphere & thermosphere (Fig. D1.4)
Ozone Layer - O3 protects living organisms from high energy (UV) radiation (Fig. D1.5)
- recent evidence suggests CFCs limitations are resulting in a recovery of the ozone layer
Weather
Conditions of temperature, atmospheric pressure, humidity, and precipitation at a particular place and time
Climate
a trend in temperature, atmospheric pressure, humidity and precipitation over a period of many years
Read p 342 - 348 Check & Reflect # 1,3 -10, 12
Climate Affects Organisms Read p 349 - 351
Three types of adaptations:
- physiological - bodily functions
- structural - body parts
- behavioral - way of acting
Climate Change
Natural climate change - evidence indicates climate change has occurred in the past. (paleoclimatology)
Enhanced climate change – some evidence may suggest that human activities are affecting climate.
Types of Evidence
anecdotal evidence - reports from people on particular events
scientific evidence - uses the scientific method and data collection
Read p 352 – 354 Do Check and Reflect # 1- 6, 8
Complete Section D1.0 Review Questions 4 - 9, 12, 14 p 355
D 2.1 Energy Relationships and the Biosphere Reference p 356 - 369
Thermal Energy
- the total energy related to the continuous random motion of a substances atoms or molecules
recall KMT: (rotational vibrational translational)
Temperature
- a measure of the average kinetic energy of the atoms or molecules of a substance
Radiant Energy - Energy that is transmitted as electromagnetic waves
Electromagnetic Spectrum – radiation classified by wavelength. Solar energy contains all wavelengths of the
spectrum. [ROYGBIV]
Radiant Energy can be:
- Transmitted
- Reflected
Albedo - a measure of the reflectivity of a surface (Fig. D2.11, D2.12, D2.9, D2.10)
- Absorbed
Insolation - amount of energy received by a region of the Earth’s surface
- depends on latitude, angle of inclination and angle of incidence
Angle of Inclination - the tilt of the Earth’s axis (Fig. D2.2 & D2.3)
- determines length of day
Earth’s orbit is elliptical:
- closest to Sun on Jan 3; farthest July 4
- solstice; shortest and longest days (June 21 & Dec. 21)
- equinox; equal day and night (Sept. 22 & March 21) (Fig D2.4)
Insolation & Angle of Inclination
- at different seasons a particular location will be closer and farther from the Sun thus will receive more
or less radiation
- accounts for reversal of seasons in Northern and Southern Hemispheres
Angle of Incidence
- the angle at which radiation strikes the surface of the Earth measured from surface perpendicular
line (Fig. D2.5)
Insolation & Angle of Incidence
- increased latitude results in radiation being spread over a larger area
- radiation at higher latitudes also passes through more atmosphere before reaching the surface
Greenhouse Effect
Natural - maintains life sustaining temperatures on Earth’s surface
Enhanced - caused by greenhouse gases such as H20(g) , CO2, CH4, N2O, ground level O3, and the
halocarbons; CFCs and HFCs which absorb and retransmit radiation (Fig. D2.13)
Radiation Budget
incoming E (solar energy input) - outgoing E (terrestrial energy output) = Net Radiation Energy
Heat balance requires that;
heat input = heat output.
- The radiation budget is held in steady state by the interaction of the atmosphere, the hydrosphere
and the lithosphere.
- The Greenhouse Effect may be upsetting this balance.
Read p 367 – 369 Check and Reflect p 369 # 1 -13, 16
Second Law of Thermodynamics
- heat (energy) flows from matter at a higher temp. to matter at a lower temp.
Energy Flows by:
1. Conduction - direct contact between particles of a substance
2. Convection - movement of particles from one place to another
3. Radiation - emission of energy in the form of particles or waves
Read p 370 - 371
Solar Energy
- arrives at the Earth as radiant energy (EMR) which is released only when it interacts with some form
of matter
- electromagnetic spectrum consists of a wide range of wavelengths of radiant energy (Fig. D2.2)
Atmospheric Pressure
- low pressure areas occur as warm air expands to become less dense
- high pressure areas occur as cold air contracts and becomes more dense
these account for convection currents and winds as air moves from high to low pressure areas
[winds are named for direction they blow from (eg easterly comes from the east)]
Coriolis Effect (p 372) - The deflection of wind, caused by convection currents, due to rotation of the Earth
- Named for Gustave Gaspard de Coriolis (1792 - 1843) who developed a mathematical description of
motion of a rotating sphere. [Note: work & KE terms also proposed by him]
- Figure D2.22 illustrates the culmination of convection currents (three cell model) and Coriolis effect
Jet Stream - a band of fast-moving air in the stratosphere
Check & Reflect pg 375 1-10, 15 & 16
Bodies of Water Affect Climate
- water has a high specific heat capacity (4.19 J/goC) thus it can act as a heat sink
specific heat capacity (c)
- the amount of heat required to raise the temperature of 1 g of a substance by 1 oC
- the ability of a substance to absorb thermal energy without raising temperature
Read p 377 - 378
Quantifying Heat Changes
Q = mc∆t
c can be determined using calorimetry or from reference tables.
Read p 378 - 380 & Example Problems D2.1 - D2.4
Do PP # 1 - 8 p 379
Review Supplemental Skills
See pg. 467 Text
Scientific Notation p 468
Problem Solving Strategies p 470
Conversion Factors & Unit Analysis p 470
Formula manipulation p 471
Change of State Triangle
- States of Matter: solid, liquid, gas
- phase changes involve the release or absorption of energy
Water Cycle transfers E
- release of energy occurs when water goes from liquid -> solid
- absorption of energy occurs when water goes from liquid -> vapor
(think of intermolecular bond changes)
- because energy is going to creating or breaking bonds no temp change occurs during phase changes
Water Cycle transfers E [evaporation, transpiration, condensation, precipitation, percolation, translocation, respiration,
combustion, excretion, run-off, aquafir]
p 384 Questions #1 - 4
Ideal Heating Curve of Water - temperature of water remains constant during a phase change
- exact temperatures at which phase changes occur will vary slightly with changes in altitude but the
shape of the graph will always be the same.
Heat of Fusion ∆H(fus)
- heat required to convert 1 kg of a substance at its melting point into its liquid phase without increasing
the temperature.
∆ Hfus = Q/m or ∆ Hfus = Q/n
- Water has a relatively high heat of fusion (333 J/g)(6.01 kJ/mol) This benefits living organisms by
moderating environmental temperatures as ice freezes.
Heat of Vaporization ∆H(vap)
aka Heat of Condensation
- amount of heat required to convert 1 kg of a substance from its liquid phase at boiling point to its
vapour phase without increasing the temperature.
∆Hvap = Q/m or ∆Hvap = Q/n
- Water has a relatively large heat of vaporization (2260 J/g)(40.65kJ/mol)
- Vaporization of water (perspiration) is a very effective way of cooling a living organism.
(excess heat damages living tissue, especially brain cells)
Evaporative Cooling
- Evaporative cooling works by reducing the average kinetic energy of the perspiration droplet and
transfer of heat from the body according to the 2 nd Law of Thermodynamics
Molar Heat of Fusion/Vaporization
Heat of fusion and vapourization are most often related as molar heats (ie rather than mass use moles)
- The formulas remain the same but the units change from kJ/g to kJ/mole
The Mole
1 mole = 6.02 x 10 23 things
To calculate the number of moles use the formula: n = m/M
Example Problems D2.5 – D2.7 p 386 – 387 as a class
Read 382 – 389 Do PP 9 – 15 p 386 Check & Reflect p 390 # 1 - 4, 6-11, 13–21
Biomes
Large geographical & climatic areas with distinguishable characteristic biota.
Examples;
- Tundra
• Tiaga
- Deciduous Forest
• Grassland
- Rainforest
• Desert
Read p 391 – 402 Do Check & Reflect # 1 - 4, 8,
Climatographs
- a graphical representation of climate data for a particular location and time period
Check & Reflect p 407 # 1 - 4, 6, 9 Review p 408
Unit D 3.0 Changes in Global Energy Transfer could Affect the Biosphere
Reference p 410 - 430
Evidence for Climate Change
4 Main Greenhouse gases
*most common & persistent
H2O; CO2*; CH4; N20
Skill Practice p 412 [Extrapolation of Data]
Read p 410 – 418 [define bold words into notes][InfoBit p 414 Why?] Check & Reflect # 1 - 6, 9 – 11
Scientific Collaboration
Collaboration - the act of working jointly.
Read p 419 - 420
Political Collaboration
Read p 421 – 425 [Note terms: Montreal Protocol, UNFCCC, ERCs, Kyoto Protocol]
Assessing Impacts
What if….?
Read p 426 – 430 Check & Reflect p 459-468
Deforestation
The clearing of trees can affect the climate of an area
CO2 released from burning & root decay
CO2 sink removed
Transpiration/moderation removed
Review questions p 431