Chapter 11 Resources and Energy Section 4 Alternative Energy Sources Notes 11-4

Solar Energy  Fact: Sun puts out enough energy every 15 minutes to meet the needs of the world for one year.  How can we capture that energy and put it to good use?  Why aren’t more people using solar energy as a source of energy?

Solar Energy  Passive System:  Sun enters the dwelling and heats the area  Windows facing the sun all day  Requires no working parts  Active System:  Uses solar collectors  Box with a glass top, placed on a high surface (roof).  Box has tubes that circulate water through the building  Cloudy days must used stored heat to maintain heat in building

Passive Solar Energy

Active Solar Energy

Solar Energy  Photovoltaic cells:  Convert sunlight directly into electricity  Found in calculators  Making energy for cities is in the experimental stage

Geothermal Energy  Water can be used that has been heated by magma  Water is heated as it flows through rock  Hot water or steam is used to create electricity  Turning turbines to create electricity in generators  Water can be pumped into the area that has the hot rocks  Through a well that has been dug  Hot water or steam can be used as a direct source of heat

Geothermal Energy  Iceland uses geothermal heat  =annotation_136343&src_vid=- ajqiPe_9Ko&feature=iv&v=h1LMFyCgs14 =annotation_136343&src_vid=- ajqiPe_9Ko&feature=iv&v=h1LMFyCgs14 =annotation_136343&src_vid=- ajqiPe_9Ko&feature=iv&v=h1LMFyCgs14  watch?v=kjpp2MQffnw&f eature=related watch?v=kjpp2MQffnw&f eature=related watch?v=kjpp2MQffnw&f eature=related

Water and Wind Energy  Hydroelectric energy:  Energy produced by running water  11% of energy in US comes from hydroelectric power plants  Water spins the turbines which spins a shaft that goes to an electric generator

Hoover Dam

Water and Wind Energy  Tides:  Dams are built to trap water at high tide  Water is released to low tide  Creates moving water and works just like it  Wind:  Small wind mills can give enough energy for homes  Large wind mill farms can produce enough for neighboring communities  Wind is not a constant and can not always be depended on

Wind Turbines

Homework Test Ch. 11 Friday, Dec. 14