Unit 2 Energy & Resources Pages & Ch. 7

Where does energy come from? §Solar Energy: 1. Energy from the sun % of energy that enters the earth system 3. Main energy source for plants 4. Causes rock to weather--forming soil 5. 40% reflected back into space

Where does energy come from? –Geothermal Energy: % of energy that enters the earth system 2.Drives crustal movements 3.Powers volcanoes, geysers, & earthquakes 4.Role in rock cycle

Where does energy come from? –Tidal Energy: 1. Energy that comes from the rise & fall of the tides % of total energy 3. Caused by pull of moon on oceans

Energy has a cycle! §Energy is neither created nor destroyed, only converted from one form to another! §Example of energy cycle: Energy from sun - plants use & store it plants die & compact over years - forms coal - coal burned to release stored energy – that energy is used to create electricity

Energy & Energy Transfer §Energy in Earth systems can exist in a number of forms (e.g., thermal energy as heat in the Earth, chemical energy stored as fossil fuels, mechanical energy as delivered by tides) and can be transformed from one state to another and move from one reservoir to another. Movement of matter and its component elements, through and between Earth’s systems, is driven by Earth’s internal (radioactive decay and gravity) and external (Sun) as primary sources of energy. Thermal energy is transferred by radiation, convection, and conduction. Fossil fuels are derived from plants and animals of the past, are nonrenewable and, therefore, are limited in availability. All sources of energy for human consumption (e.g., solar, wind, nuclear, ethanol, hydrogen, geothermal, hydroelectric) have advantages and disadvantages.

Energy Transfer on Earth Radiation from the Sun heats the land and water of Earth which in turn heats the atmosphere. Thermal energy produces movement of matter (convection) observed in wind and ocean currents. Thermal energy also moves between the ocean and the atmosphere when water evaporates and condenses.

White board You decide... §One day you decide to order a juicy and delicious hamburger from your favorite restaurant. Consider the thick 100% all beef patty embedded between the buns and the energy it will provide your body. Trace how/where the energy from this meat comes from. Name all Earth spheres involved. §Is energy destroyed in this process? Why or why not?

Environment The environment includes all of the Earth’s resources, influences, and conditions near the Earth’s surface.

What is a “resource?” What are some resources you use every day? Examples: Air Water Oxygen Minerals Metals Petroleum

Renewable vs. Nonrenewable Renewable Nonrenewable ~ Replaced in nature at a rate close to its rate of use. ~ Amount used = Amount replaced ~ Examples: food, solar energy, soil. ~ exists in “fixed amounts” -used up faster than can be replaced ~ Amount used > Amount replaced ~ Example: petroleum, natural gas, uranium, salt.

Renewable or Nonrenewable? Fossil Fuels Water Minerals Solar Power Fruit

Earth’s Minerals Two types : Metals and Nonmetals Metals are of more economic importance. All important metals are obtained from “minerals.” Minerals are nonrenewable. Ore is rock that contains enough metallic element to make separation profitable. 1. Most metals can easily be separated from surrounding rock (gold, silver)

Minerals (nonrenewable resource) §2. Some not easily separated: Ore minerals l *Ore mineral – valuable mineral (Iron, Copper) l * Gangue – the rest of the rock (Quartz, Feldspar, Calcite) l *Separation can be costly!! l 3. Some can be used as they are, others have to be processed

Minerals (nonrenewable resource) §4. Reserves – known deposits of mineral worth mining –**U.S. has some large mineral deposits but… one of the greatest consumers!! l ** Most reserves estimated to be used up w/in next 60 years!!

Minerals (nonrenewable resource) §5. What can we do to keep from running out? –Recycle/reuse –Conserve (cut back on use) –Use an alternative substance

Mining Concerns: 1. Destroys landscape 2. Leaves craters 3. Leaves piles of waste rock 4. Surface mining removes soil (supports little life) 5. The top soil only renews itself 1-2 inches every 1000 years 6. Runoff may become acidic or toxic

Risks and Disadvantages Using nonrenewable resources causes pollution to land, water, and air. Renewable energy sources have their problems too!

Nonrenewable Energy Resources Formed from remains of organism that lived millions of years ago Consist mostly of carbon Burning releases stored energy, CO2 and other toxins Primary energy source for power plants…… COAL!! Equation: C x H y + O 2 → H 2 O + CO 2 + ENERGY Hydrocarbon (Fuel) Fossil Fuels

Energy Resources—Nonrenewable §Coal (Fossil Fuels) Large U.S. Deposits l Steps of formation: l 1. Ferns, mosses, trees containing C,H,O l 2. Die & compress losing H & O = PEAT l 3. Lose more H & O = LIGNITE l 4. Lose more H & O = BITUMINOUS COAL l 5. Lose more H & O = ANTHRACITE (Mostly carbon) l ** The more C, the more energy released when burned! Large U.S DEPOSITS

Nonrenewable Energy Resources (Fossil Fuels) §Natural Gas (CH 4 ) l Usually exists above the petroleum layer l Pressure from gas brings oil to surface Methane

Nonrenewable Energy Resources (Fossil Fuels) §Petroleum/oil l Liquid hydrocarbons l Must drill wells in oil-bearing rock (sandstone or limestone)

Some Problems (with nonrenewable energy use): §1. Mining, drilling, nuclear accidents are risky §2. Nuclear reactors produce radioactive by- products §3. Nuclear waste last thousands of years §4. Burning of fossil fuels releases CO 2 and other pollutants that can create acid rain §5. Limited supplies of fossil fuels threatens protected land §6. Oil spills are risky

Renewable Energy Resources §Water (Hydroelectric Power)– water power used to produce electricity 1. Water moves turbines which move generators 2. More efficient method than using coal or uranium (steam must be made first) (Click on picture for film)

Renewable Energy Resources §Wind– Wind power used to produce electricity 1. Windmills capture air 2. Turbines move generators that make electricity 3. Power depends on wind speed, windmill blades, windmill efficiency 4. Windmill farms generate much electricity

Renewable Energy Resources §Sun (Solar Power)– solar energy used to produce heat/electricity 1. Passive system – collects & stores solar energy Ex. Greenhouses, homes, pools

Solar energy continued §2. Active system – collects, stores & distributes energy. These use pumps to move warmed liquids or fans to move warmed air to the desire location for use or storage.

Passive & Active Systems Source:DOE

Solar energy continued §3. Solar photovoltaic—use cells that convert solar energy directly into electricity EX. Solar cells on spacecraft, calculators, homes

Renewable Energy Resources §Biomass—uses a biological process to provide energy. Wood or plant material can be harvested and burned to produce heat and then steam to move a turbine… Click on picture for movie §Plant material can decompose or ferment to make a fuel.

Renewable Energy Resources §Geothermal – heat from earth’s interior is converted to electricity 1. Volcanic and geyser regions are ideal 2. Hot water or steam is piped to a turbine that moves a generator

Some Problems: (with renewable energy sources) 1. May have limited areas/times where/when it can work effectively 2. Windmills interfering w/ TV & radio reception 3. Energy cannot be stored effectively 4. Chemical-rich, superheated geyser water can pollute lakes & streams 5. Cave-ins are risky

What can YOU do about helping now? §1. Conservation – the protection, restoration, and management of natural resources l Research more efficient & improved methods of resource use l Dress appropriately for the temperature l Make wise choices at home

Energy Summary §Click picture for film

What can YOU do about helping now? §2. Reduce l reduce gasoline consumption Gasohol use Use of hybrid cars Carpool l reduce electricity use (reducing fossil fuel consumption) §3. Recycle – collect and reuse materials from waste