Earth and Space Science Notes

Chapter 10: Space Systems

The Age of Earth

• Earth is estimated to be about 4.6 billion years old.
• Scientists use three major types of evidence to determine the age of Earth and objects on it:
  • Landforms
  • Fossils
  • Radiometric dating

Landforms

• The processes that build up and wear down landforms today are the same processes that have been at work throughout Earth's history.
• Studying these processes helps scientists understand Earth's history by examining the structure and composition of landforms.
• Sedimentary Rock Formation:
  • Sediment (weathered material) settles and becomes compacted into layers of sedimentary rock over time.
  • New sediment is added to the top, making the youngest layers at the top and the oldest layers at the bottom.
  • This allows scientists to determine the relative age of layers in a landform.

Fossils

• Fossils are remains (shells or bones) or evidence (imprints) left behind by dead organisms.
• They are most often found in sedimentary rock.
  • The age of a fossil can be determined by the layer it is found in.
  • Conversely, a fossil of known age can provide information about the age of the layer it is found in.
• Comparing rock layers and fossils provides information about the relative age of objects on Earth.

Radiometric Dating

• Provides the exact, or absolute, age of objects on Earth.
• Elements have a specific number of protons in their nucleus.
• Radioactive Isotopes:
  • Some elements have radioactive isotopes that turn into another element by losing a proton.
  • Carbon-14 and uranium-235 are radioactive isotopes used in radiometric dating.
• Half-Life:
  • The amount of time it takes for half of an isotope's atoms to change into another element.
  • For example, uranium-235 (U) has a half-life of 1 billion years.
    • After 1 billion years, half of the U-235 atoms in a rock will have turned into lead (Pb) atoms.
    • After 2 billion years, only one-quarter of the original U-235 atoms will remain.
  • By looking at the number of U-235 atoms that remain, scientists can determine the age of the rock.

The Solar System

• Solar means sun.
• Our solar system consists of the sun and all objects that orbit it.
• The sun is a star located at the center of our solar system.
• Gravity:
  • All objects exert gravitational force on each other.
  • The sun’s gravity keeps all other objects orbiting around it because it is the largest object in the solar system.
• Planets:
  • After the sun, the largest objects in the solar system are the round-shaped planets.
• Two Groups of Planets:
  • Terrestrial Planets:
    • The four smaller planets located closest to the sun.
    • They all have rocky surfaces.
  • Gas Giants:
    • The four larger planets farther from the sun.
    • They all have gaseous surfaces.
  • Dwarf Planets:
    • A new category of planet was created called dwarf planets or minor planets.
    • One example of these objects is Pluto.
• Moons:
  • Any natural object in space that orbits a planet.
  • Earth has one moon.
  • A planet may have no moons (like Mercury) or several moons (like Jupiter).
• Asteroids:
  • A large, irregularly shaped chunk of rock.
  • Most are found in a band called the asteroid belt, which separates the gas giants from the terrestrial planets.
• Comets:
  • Made up of frozen gases and dust particles and are usually smaller than asteroids.
  • Some comets orbit the sun continuously.
  • Others orbit the sun once and then travel off into space.
  • Halley's Comet is a famous comet that continuously orbits the sun, passing by Earth every 76 years.

Interactions Between Earth and the Solar System

• Earth orbits (revolves) around the sun every 365.25 days, which we call a year.
• Earth also spins (rotates) on an axis every 24 hours, which we call a day.
• Eclipses:
  • Caused by the positions of the sun and moon in relation to Earth.
  • Occur when one object in space blocks light from reaching another object.
  • Solar Eclipse:
    • The moon blocks sunlight from reaching Earth.
  • Lunar Eclipse:
    • Earth blocks sunlight from reaching the moon.
• Tides:
  • The daily rises and falls of ocean levels.
  • High Tide:
    • The ocean reaches its highest point on the shore.
  • Low Tide:
    • The ocean reaches its lowest point on the shore.
  • Shorelines experience two high tides and two low tides every day.
  • Caused by the pull of the moon's gravity as Earth rotates on its axis.
    • The moon's gravity pulls on the water in the ocean, causing it to bulge on the sides closest to and opposite of the moon.
    • Shores within the bulge areas experience high tide.
    • Shores not located in the bulge areas experience low tide.
    • As Earth rotates, the bulges stay in line with the moon, causing different locations to experience high tide at different times throughout a day.
  • The sun's gravitational force also affects tides.
  • Spring Tides:
    • When the sun is in line with the moon (new moon and full moon), they both pull the ocean in the same direction, causing extra high and extra low tides.
  • Neap Tides:
    • When the sun and moon are perpendicular to each other (first quarter and third quarter moon), they pull the ocean in different directions, causing only minor differences in high and low tides.

The Universe

• The total of all matter and energy that exists.
• The universe contains many other solar systems, as well as other types of objects.
• Stars:
  • Our sun is a star.
  • A ball of gas that produces its own light and heat.
• Constellations:
  • A recognized pattern of stars in the night sky.
  • Examples include Ursa Major (the Big Dipper) and Orion.
  • Different constellations are visible at different times of the year due to Earth's orbit.
  • Scientists can identify the area of space that is visible by the constellations present.
• Galaxies:
  • A massive group of stars, gas, dust, and dark matter held together by gravity.
  • Our solar system is part of the Milky Way Galaxy, along with about 200 billion other stars.
  • The universe is estimated to contain at least a billion other galaxies.

Types of Galaxies

• Spiral
• Elliptical
• Irregular

Age and Development of the Universe

• Scientists believe that the universe formed 10 to 20 billion years ago.
• Big Bang Theory:
  • The most widely accepted model of how the universe began.
  • All of the matter and energy in the universe was once contained in an area the size of an atom.
  • An enormous explosion (Big Bang) caused the matter and energy to rapidly expand outward, creating the universe.
  • Scientists believe the universe has been expanding ever since.

Age and Development of Stars

• Stars vary in composition, size, and age.
• They all follow the same basic life cycle.
• Nebula:
  • A star forms in a cloud of gas and dust.
  • Gravity causes some gas and dust to pull inward, forming a protostar.
• Protostar:
  • Then turns into a main sequence star.
• Main Sequence Star:
  • A star spends most of its life as a main sequence star.
  • The fusion of hydrogen (H) atoms into helium (He) atoms causes main sequence stars to release heat and light.
• Black Dwarf:
  • A main sequence star that has run out of fuel will eventually stop glowing and become a black dwarf.
• White Dwarf:
  • Stars that are close to dying out.
• Supergiant Stars:
  • Sometimes a protostar is too massive to become a main sequence star.
  • Die in a sudden explosion called a supernova.
• Black Hole:
  • The death of a supergiant can result in a black hole.

Chapter 11: Earth Systems

The Structure of Earth

• There are three main layers that make up Earth's interior:
  • Crust
  • Mantle
  • Core
• Each layer has its own materials, properties, and conditions.

Crust

• Outermost layer.
• Thin outer layer of rock that includes both the dry land and the ocean floor.
• Oceanic Crust:
  • Beneath the ocean.
  • Consists mostly of dense, dark, finely textured rock called basalt.
• Continental Crust:
  • Forms the continents.
  • Consists mainly of granite, a lighter, less dense rock with larger crystals than those found in basalt.

Mantle

• Underneath the crust.
• Composed mainly of silicate rocks that contain lots of iron, nickel, and magnesium.
• Lithosphere:
  • The uppermost part of the mantle and the crust are similar.
  • Together, they form a rigid layer.
• Asthenosphere:
  • Below the lithosphere, temperature and pressure increase with depth, resulting in less rigid rock that is somewhat bendable and plastic-like.
  • A soft layer of the mantle where material can flow freely.

Core

• Consists of two parts:
  • Molten, liquid outer core
  • Solid, dense inner core.
• Both parts are made up of metals like iron and nickel.
• Together, the inner and outer cores are just slightly smaller than the moon.

Tectonic Plates

• Oceanic crust and continental crust come together in sections to make up seven primary tectonic plates and many other smaller plates.
• All of the tectonic plates have names that usually refer to their proximity to certain landmasses, oceans, or regions of the globe.
• Convection Currents:
  • Plates slowly move, or float, on the mantle by means of convection currents.
  • Hot currents of molten rock that cause the plates above them to move one or two centimeters each year.
• The motion of the tectonic plates explains the formation of ocean basins, mountains, and continental shelves.
• Continental Shelves:
  • Gently sloping, shallow sections of the ocean floor that extend outward from the edge of a continent.
• Ocean Basins:
  • Vast geologic regions below sea level that cover nearly 75% of Earth's surface.
  • Contain features such as deep-sea trenches and mountain-like ocean ridges.

Plate Boundaries

• Transform Boundary:
  • One plate is sliding past another.
• Divergent Boundary:
  • Two plates are pulling apart.
• Convergent Boundary:
  • Two plates are colliding with each other.
  • This collision can bring together two sections of oceanic crust, two sections of continental crust, or one of each.
  • The relative densities of the two plates determine which plate comes out on top.
• Mountains:
  • Made when one plate slides on top of another plate.
  • Fold Mountains:
    • Created when the collision of two plates squeezes the two plates together.
    • The layers of rock are slowly pushed toward each other and rise upward in folds.
• Trenches:
  • Created when one plate is forced down into the mantle beneath a second plate.
  • Volcanoes can occur in areas where trenches are created.
    • A volcano is a weak spot in the crust.
    • When heat deep beneath Earth's surface melts the plate material that was forced down, molten rock called magma is sent to the surface.
    • Magma that reaches Earth's surface is called lava.
• Earthquakes:
  • Created by the movement of two tectonic plates sliding past each other.
  • Formed by the shifting and breaking of the surface rocks.
  • The break in the crust where earthquakes can occur is called a fault.
  • Faults usually occur along plate boundaries.

Earth's Atmosphere

• Scientists estimate that Earth formed around 4.6 billion years ago.
• It is thought that gases from Earth's core were expelled from volcanoes.
• Earth's atmosphere is the envelope of gases that now surrounds the planet.
• These gases are most dense at sea level and become increasingly thinner higher in the atmosphere.
• The atmosphere exists as a series of layers, each having its own characteristics.

Layers of Earth's Atmosphere:

• Troposphere
  • 0-10 km
  • Lowest region of the atmosphere
  • Sustains life
  • Where all weather occurs
  • Increased wind speeds with height
  • Fall in pressure with height
  • Temperature decreases with increasing altitude ($6.4$ degrees per $1000$ m)
  • Unstable layer due to presence of clouds, pollution, water vapor, and dust
• Stratosphere
  • 10-30 km
  • Temperatures increase with height
  • Ozone, a form of oxygen, is concentrated here
  • Ozone absorbs ultraviolet (UV) radiation from the sun and warms this layer
  • Winds increase with height but pressure falls
  • Some jet aircraft fly here
• Mesosphere
  • 30-50 km
  • Rapid fall in temperature with height caused by lack of water vapor, clouds, or dust
  • Temperatures very low (as low as $-130$ degrees Celsius) and winds high
  • Space shuttle orbits within this layer
• Thermosphere
  • 50-400 km
  • Rapid increase in temperature with height due to steady influx of solar energy
  • Temperatures in excess of $1000$ degrees Celsius
• Ionosphere
  • Extending 50-600 km above sea level
  • Electrified region that contains large concentrations of ions and free electrons
  • Important for radio wave propagation
• Exosphere
  • Extending 480 km above sea level
  • Merges into the regions of Earth's magnetic field, radiation belt, and outer space

Atmospheric Gases

• The air around us, part of the tropospheric layer, is a mixture of gases.
  • It contains 78% nitrogen, 20% oxygen, and trace amounts of several other gases, including hydrogen and carbon dioxide.
• Greenhouse Effect:
  • Gases in Earth's atmosphere hold in heat from the sun and help to support life in the troposphere.
  • Greenhouse gases include water vapor, carbon dioxide, and methane.

Effects of Gases on Earth

• Human activities can add greenhouse gases to the atmosphere, contributing to steadily increasing temperatures over the last century.
• Global Warming:
  • A gradual increase in the temperature of Earth's atmosphere that can lead to climate change.
• Ozone Layer:
  • Ozone ($O_3$) is a molecule made up of three oxygen atoms.
  • Works as a protective blanket in the stratosphere, filtering harmful ultraviolet (UV) rays from the sun before they reach Earth.
  • Scientists have identified areas where the ozone layer has become increasingly thin.
  • Chlorofluorocarbons (CFCs):
    • Scientists believe that a group of chlorine compounds are the main culprit.
    • Were widely used in refrigerators, air conditioners, and spray cans until the late 1980s.
    • Unlike most chemical compounds released into the air, CFCs do not break down easily or quickly.
    • Instead, they last for decades, rising into the stratosphere where ultraviolet radiation breaks down the CFC molecules into chlorine.
    • The chlorine atoms then break down ozone into oxygen atoms, destroying the protective ozone layer.

Sources of Air Pollution

• Primary Pollutants
  • Natural
  • Stationary
  • Mobile
• Secondary Pollutants
  • Stationary
  • Natural

Main Air Pollutants

• Particles-measured by Air Particle Index (API)
  • Source: Internal combustion engines (e.g., cars and trucks), Industry (e.g., factories), Burning wood, Cigarette smoke
  • Effects on Human Health: Long-term exposure is linked to Lung cancer, Heart disease, Lung disease, Asthma attacks
• Nitrogen dioxide ($NO_2$)
  • Source: Motor vehicles are the biggest contributors., Other combustion processes
  • Effects on Human Health: Exposure to high levels of $NO_2$ may lead to lung damage or respiratory disease., It has also been linked to asthma and respiratory problems.
• Carbon monoxide (CO)
  • Source: Motor vehicle exhaust and burning of materials such as coal, oil, and wood. It is also released from industrial processes and waste incineration.
  • Effects on Human Health: When inhaled, carbon monoxide enters the bloodstream and disrupts the supply of oxygen to the body's tissues.
• Lead (Pb)
  • Source: Is largely derived from the combustion of lead additives in motor fuels as well as lead smelting.
  • Effects on Human Health: Retards learning in children and the development of their nervous system.
• Hydrocarbons (HC)- chemical compounds composed of hydrogen and carbon atoms
  • Source: Most fuel combustion processes result in the release of hydrocarbons to the environment. The largest fuel sources are natural gas and petrol. They are also a component of the smoke from wood fires.
  • Effects on Human Health: Exposure can cause headaches or nausea, while some compounds may cause cancer. Some may also damage plants.

Weathering and Erosion

• Two of the primary agents of change on Earth are wind and water.
• Wind and water interact powerfully to constantly change Earth's surface through weathering and erosion.
• Weathering:
  • The process of breaking down or dissolving minerals and rocks on Earth's surface.
  • Water, ice, temperature changes, acids, salt, plants, and animals can all be agents of weathering.
• Erosion:
  • Once rock is broken down, wind, water, and gravity can transport the bits of rocks and minerals away.
  • No rock on Earth's surface is hard enough to resist weathering.
• Weathering can be a mechanical or a chemical process, and often the two types work together.

Chemical Weathering

• Occurs when the materials that make up rocks and soil are changed by chemical means.
• Sometimes carbon dioxide from the soil or air combines with water to produce carbonic acid.
  • This is a weak acid that can dissolve rock and is particularly effective on limestone.
• Rust, through the process of oxidation, is also an agent of chemical weathering.

Mechanical Weathering

• Causes rocks to crumble.
• Freeze-Thaw Process:
  • Water enters cracks in the rock.
  • When the temperatures drop and the water freezes, it expands.
  • This places pressure on the rocks around it, causing rocks to crack and split over time.

Wind

• Can also be an agent of weathering.
• Wind Abrasion:
  • The wind carries dust, sand, and other small grit particles that repeatedly strike the surface of rocks, resulting in a gradual wearing away of the rock.
  • Can be compared to sandblasting.
• Wind is the movement and flow of gases on Earth's surface.
• It is caused by the uneven heating of the surface by the sun.
• Winds are generated by differences in atmospheric pressure.
  • For example, at the equator, the sun warms the water and land more than on the rest of the planet.
    • This warm equatorial air rises higher into the atmosphere and then flows toward the poles (Low pressure system).
    • A high pressure system composed of dense, cooler air flows toward the equator to replace the heated air.
• Generally, winds blow from high pressure areas to low pressure areas.
• Front:
  • The boundary between a high pressure area and a low pressure area.
  • The complex relationships between fronts result in different types of weather and wind patterns.
• Prevailing Winds:
  • Winds that regularly blow from a single direction over a specific area of Earth.
• Convergence Zones:
  • Areas where prevailing winds meet.
  • These winds usually blow east-west rather than north-south because of the Coriolis effect.
• Coriolis Effect:
  • Earth's rotation generates a circulation pattern that makes wind systems twist counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
  • Causes some winds to travel along the edges of the high and low pressure systems.

The Oceans

• Over 70% of Earth's surface is covered by water.
• The ocean is what makes Earth appear blue when viewed from space and what makes all life on Earth possible.
• Ocean water is a mixture of water and salts, with an average salinity of about $3.5$.
  • This means that for every $1000$ grams of seawater, there are approximately $35$ grams of dissolved salts.
  • The molecules that compose those salts are predominantly chlorine and sodium ions.
  • Other ions found in seawater are sulfates, magnesium, calcium, and potassium.
  • Seawater also contains dissolved gases such as nitrogen, oxygen, and carbon dioxide.
  • It is also denser than both pure water and freshwater because the dissolved salts add mass without contributing much to the overall volume of the water.

Ocean Currents

• Streams of water running through a larger body of water that are set in motion by a variety of factors.
• Ocean currents can be either warm or cold.
  • The temperature of a current affects the temperature of the coastal areas toward which it flows.
• Currents flowing near the surface of the oceans transport warm water from the equator to the poles and cool water back toward the equator.
• The paths of ocean currents are also influenced by The Coriolis effect.
• Cold, deep currents transport oxygen and nutrients to organisms living in the ocean's depths.
• Ocean food chains are constantly recycled because of the upwelling of ocean currents.
• Upwelling:
  • When winds push surface water away from the shore, deep currents of cold water rise to take its place.
  • Nutrients from various depths become available to nourish new plankton growth, which provides food for fish.
• Gulf Stream:
  • A warm surface current that originates in the tropical Caribbean Sea and influences weather patterns all over the globe.
• El Niño:
  • Warm-water currents sometimes displace the cold Humboldt Current along the west coast of South America, affecting weather patterns over large areas of the globe.

Ocean Zones

• Surface Zone:
  • Smallest and warmest, reaching down about 200 meters and making up only 5% of the ocean's depth.
• Twilight Zone:
  • Making up about 20% of the ocean depths, reaching from 200 meters to 1000 meters in depth.
  • It is cold and dimly lit to dark.
• Deep Ocean Zone:
  • Making up 75% of the ocean, there is constant cold and no sunlight.

Coral Reefs

• Can be found in the sunny and shallow surface zones of the ocean.
• Created by colonies of tiny coral animals that produce a hard structure around their soft bodies.
• Zooxanthellae:
  • Microscopic, symbiotic algae live in the bodies of coral animals and provide them with food produced by photosynthesis.
• Coral reefs provide diverse habitats for many organisms.
  • One-quarter of all ocean species depend on coral reefs for food and shelter.
  • Coral reef ecosystems also have tremendous impact on humans, providing food, shoreline protection from storms, ingredients for medicines, and jobs based on tourism.
• Humans are also the greatest threat to coral reefs, as pollution, destructive fishing, acidification of ocean water, and invasive species have all taken a negative toll.

Chapter 12: Interactions Between Earth's Systems and Living Things

Cycles in Nature

• Every living thing depends upon oxygen, nitrogen, and carbon dioxide in the atmosphere.
• Water is also key to life on Earth.
• Nitrogen Cycle:
  • Nitrogen moves from the air to the soil, into living things, and back into the air.
    • Nitrogen enters the food chain when nitrogen compounds called nitrates are absorbed from the soil by plants.
    • Plants convert nitrates into usable nitrogen compounds which, are transferred between organisms through feeding (trophic) levels starting when primary consumers feed on the plants.
    • Decaying plants and animals also return nitrogen to the soil with the help of nitrogen-fixing bacteria.
    • These bacteria produce nitrates from the nitrogen compounds found in decaying matter.
    • Denitrifying bacteria play a role when they return nitrogen to the atmosphere by converting nitrates to nitrogen gas.
• Carbon Cycle:
  • A system involving living things and the nonliving matter in Earth's crust, oceans, and atmosphere.
    • In this cycle, carbon is transferred from one part of the environment to another.
    • The energy that drives the cycle is provided by the sun and Earth's core.
    • Organic compounds, such as carbohydrates, proteins, and lipids, are formed in producers when carbon is made usable (fixed) from carbon dioxide by the process of photosynthesis.
    • The fixed carbon is moved through the feeding levels from primary consumers to secondary consumers and beyond.
    • Carbon continues to be recycled through the processes of respiration, decay by decomposers, and the combustion of fossil fuels.
    • Fossil fuels (petroleum, natural gas, or coal) are drilled or mined from underground deposits and, are burned to extract energy.
    • The burning releases gases, including carbon dioxide, into the atmosphere.
    • Excess carbon dioxide contributes to the greenhouse effect.
• Oxygen Cycle:
  • describes the movement of oxygen within the atmosphere, organisms, and nonliving matter on Earth's crust.
    • The driving force in the oxygen cycle is photosynthesis.
    • Producers use solar energy for photosynthesis.
    • Using that energy, carbon dioxide and water are converted to glucose and oxygen.
    • Plants use some glucose to fuel respiration.
    • Glucose is also used in the making of fats and proteins.
• Water Cycle:
  • describes the continuous process of transporting water from the oceans to the atmosphere, then to the land, and then returning it to the oceans.
    • The processes of evaporation, condensation, and precipitation make up the water cycle.

Natural Hazards

• A natural hazard is the threat of a natural event that can have a negative effect on organisms and the environment.
• There is a wide range of events that can be classified as natural hazards, from droughts to volcanic explosions.
• In order for a physical event to be defined as hazardous, there must be the potential for the loss of life.
• Certain areas are more vulnerable to natural hazards such as, cities built on or near tectonic plate boundaries that, are far more likely to be negatively impacted by earthquakes, and Coastal cities that are, much more vulnerable to hurricanes.
• Additionally, the impact of hazards can be increased by human activity such as, flooding and landslides that, are more likely to result from heavy rainfall if poor farming practices have removed vegetation from hill slopes.

Natural Hazard Frequency

• Earthquakes:
  • 0. 11 (11% probability) for 10 fatalities
  • 0. 001 for 1000 fatalities
• Hurricanes:
  • 0. 39 for 10 fatalities
  • 0. 06 for 1000 fatalities
• Floods:
  • 0. 86 for 10 fatalities
  • 0. 004 for 1000 fatalities
• Tornados:
  • 0. 96 for 10 fatalities
  • 0. 006 for 1000 fatalities

Effects of Natural Hazards

• The short- and long-term effects that a natural hazard has on an area depend on a number of factors.
• In general, the less economically developed a country is, the more damage it is likely to sustain, both economically and in terms of loss of life.
• The more people there are and the more vulnerable they are to a disaster, the greater the impact of a natural hazard.

Differences Between Less and More Developed Countries

• Population densities are higherin less developed countries while, populations are more spread out in more developed countries.
• Less developed countries lack the financial authority to demand strict building legislation codes while, well-financed governments in more developed countries require strict building codes.
• Populations in less developed countries have increased vulnerability, because people are often not taught where to go during an emergency while, more developed countries are educated about what to do in the event of a hazard
• Homes are rarely insured less developed countries while, Homes can be insured against damage from hazards and offsets the cost of rebuilding in more developed countries.
• Less developed countries, economies are dependent on a cash crop; if a hazard wipes out the entire crop, then the whole economy suffers, while a more developed countries Economy has more stability.
• Power, communication, water and sewage systems sustain long-term damage in less developed countries while, Highly organized emergency services and communications ensures the population in need of help receives assistance as quickly as possible, this reduces the spread of disease and death in more developed countries.Clearly, the short- and long-term effects from a natural hazard can be markedly different, depending on the area of the world in which the hazard occurs.
• Short-term effects in a more developed area will include loss of power and communication, damage to water and sewage systems, infrastructure damage, financial loss, injuries, sickness, and death.
• In a less developed area, many of those short-term effects become long-term effects, and disasters may eventually lead to failed economies and outbreaks of disease.
• More developed areas typically have few, if any, long-term effects.

Hazard Mitigation

• Mitigation is an effort to reduce the loss of property and life by lessening the impact of the disaster.
• Structural Mitigation Techniques:
  • Involve building dams, dikes, levees, and containment ponds to hold water or slow its flow.
  • Other structures, like storm shelters, are designed for the specific purpose of saving lives and, are common in tornado-prone areas.
• Nonstructural Mitigation Techniques:
  • Building practices such as land use regulations, building codes, and zoning ordinances are effective nonstructural mitigation techniques.
  • Building codes specify what types of materials can be used to build homes and businesses based on criteria such as strength, durability, flammability, and resistance to water and wind.

Natural Resources

• The wind, water, and rock that can be sources of natural hazards also supply us with a wide range of natural resources that are essential for our daily lives.

Renewable Resources

• Resources that will never run out, either naturally or through proper management.
  • Naturally Occurring:
    • Wind
    • Waves
    • Air
    • Sunlight
  • Require Proper Management to Remain Sustainable:
    • Forests
    • Soil
    • Water
    • Fish
    • Wildlife

Nonrenewable Resources

• Resources that will eventually run out; they have a finite supply.
  • Minerals:
    • Diamonds
    • Iron ore (used to make steel)
  • Nuclear Energy:
    • Relies on minerals such as uranium and plutonium.
    • Minerals are extracted from rocks through the process of mining.
    • Fossil Fuels:
    • Are primarily used as energy sources and include oil, coal, and natural gas.
    • Oil and natural gas are thought to have formed slowly, over millions of years, from the decomposition of plants and animals.
    • Over time, the dead organisms were compressed between layers of sediment that added pressure.
    • Eventually, rock was formed, and, in areas that lacked oxygen, heat and pressure turned the remains of the organisms into oil and natural gas.
• Some of those rocks, such as limestone or sandstone, have networks of small holes called pores.
• Oil (a liquid) seeps into the holes in the rocks.
• Natural gas also diffuses into porous rocks.
• Oil and natural gas are extracted using techniques such as drilling and hydraulic fracturing.

Sustainability of Resources

• Untapped deposits of coal and oil are becoming increasingly difficult to locate.
• There are serious concerns about how much is left and how long the reserves will last.
• Some estimates suggest that oil reserves could run out in approximately 50 years, and coal reserves in approximately 300 years.
• Estimates spotlight a need for greater fuel efficiency and a decreased reliance on nonrenewable resources for energy.
• As dependence on renewable energy sources grows, people must also accept the responsibility to properly manage and sustain those sources.