Natural Resources

 People depend on the environment for food, clothing, and fuels to heat and light their homes.  Natural resources: materials useful or necessary for the survival of living things Ex. minerals, trees eenvironment/naturalresources/

Natural Resources, cont.  Natural resources can be converted into synthetic materials. Ex. Plants from the tropical rainforest can be converted to produce important medicines. In order for natural resources to convert into new products, they undergo a chemical process.

Ex. How is plastic made? Dg-Kc

Where does it come from? (page 537 leopard)  Almost everything you use comes from natural resources or materials that come from the environment. Can you identify the natural resources used to make a common object?  Task: Choose an object from around the classroom. Determine the natural resources required to make the object.

Chemical Changes  Chemical changes produce new substances that have different properties from those of the original substances.  Atoms rearrange to form new substances by forming different elements or compounds.

Signs of Chemical Change 1. Changing color and odor 2. Burning 3. Rusting 4. Formation of a gas (bubbles) l-and-manmade-materials

Chemical Properties  Flammability  Reacts with oxygen, water, vinegar, etc.  Reacts in the presence of electricity, light, heat, etc.

Something New!  In a chemical change, a new substance is formed. Ex. Sugar, eggs, flour, and other ingredients become a cake.  If a chemical change has occurred, it is not reversible.  andchemistry/propertychanges/ andchemistry/propertychanges/

Fossil Fuels—Sources of Energy  Fuels formed in the Earth’s crust over hundreds of millions of years.  1. Gasoline—made from oil: cars, buses, trains, airplanes, plastics 2. Coal: power plants to produce electricity 3. Natural gas: used in manufacturing, for heating and cooking, also vehicle fuel

Fossil fuels, cont.  Power plants burn coal/natural gas. This results in chemical changes. ytechnology/fossilfuels/

Photochemical Smog  Sunlight reacts with waste gases from the burning of fossil fuels and forms a type of air pollution  Smog darkens the air, and the air smells bad.

Effects of Burning Fossil Fuels  Pollution: the contamination of the environment with substances that are harmful to life Ex. smoke, toxic chemicals  Most pollution occurs because of human actions, such as burning of fossil fuels.

Global Warming  Scientific observation that Earth’s average surface temperature is increasing  Can lead to climate change  Changes to ecosystems and food webs  Increases in number and severity of floods and droughts  Coastal flooding  TJCugs TJCugs

Acid Precipitation  Acid rain: forms when waste gases from cars and power plants combine with moisture in the air.  Coal-burning power plants produce a gas that combines with moisture to make sulfuric acid.  Cars and trucks make a gas that helps form nitric acid.

Air Pollution  gileenvironment/airpollution/ gileenvironment/airpollution/

Acid Rain, cont.  Pollutes soil  Can kill plants  Contributes to water pollution  Can damage buildings  67YkDE 67YkDE

Pollution

How do air pollutants move? (page 547 leopard)  Small particles of pollutants can be transported by air movement. Once a pollutant is in the air, how far can it travel?

Alternatives to Fossil Fuels  Reducing fossil fuels can be done by developing other sources of energy.  Alternative energy sources include: 1. Water 2. Wind 3. Atomic energy 4. Solar energy 5. Solar cells

Water Power  Hydroelectric power: electricity that is produced when the energy of falling water is used to turn the turbines of an electric generator  No fuel is burned, therefore no air pollution rgytechnology/dams/ rgytechnology/dams/

Environmental concerns  A dam must be built. The dam raises water levels to produce energy needed for electricity generation.  Many acres behind the dam are flooded.  Land habitats are destroyed.  NTQix8 NTQix8

Water Power  rce/phy03.sci.phys.energy.hooverelec/h oover-dam-and-hydroelectric-power/ rce/phy03.sci.phys.energy.hooverelec/h oover-dam-and-hydroelectric-power/

Wind Power  Wind turns the blades of a turbine, which powers an electric generator.  Winds must be blowing at least 32 km/hr for energy to be produced.  No wind, no electricity is produced.  rgytechnology/windenergy/ rgytechnology/windenergy/

Nuclear Power  Makes use of huge amounts of energy from the nuclei of atoms.  Energy is released when the nucleus is split.  The energy is used to produce steam that rotates the turbine blades of an electric generator.  Bad effect: radioactive wastes that can seriously harm living organisms.

Nuclear Energy  shistory/hiroshimaandnagasaki/ shistory/hiroshimaandnagasaki/

Solar Energy  Sun’s energy  Large windows are used to allow warm sunshine into buildings during the day.  Floors and walls are made of materials that absorb heat during the day.  At night, the stored heat is released slowly, keeping buildings warm.

Solar Cells  Photovoltaic cells: turn sunlight into electric current.  Small and easy to use  Make electricity only in sunlight  Batteries needed to store electricity at night  Too expensive to use for generating large amounts of electricity Ex. solar powered calculator

Solar Energy  AIcCQLQ AIcCQLQ