Natural Science Exam Questions with Latest Update

What about alternatives to fossil fuels? - ANSWER-Neither the availability or cost of fossil fuels, nor the upfront cost in public opinion of nuclear fuel, look very promising solar energy - ANSWER-energy that comes from the sun Used by the Greeks 2000 years ago and the Anasazi Indians of the desert Solar energy technologies - ANSWER-There are some interesting solar technology such as solar furnaces and photovoltaic cells- Then silicone we first which admit electrons in produces electricity Three basic types of photovoltaic or solar cells - ANSWER-Single crystal cells (monocrystalline) Polycrystalline cells Amorphous silicon cells single crystal cells (monocrystalline) - ANSWER-Made in long cylinders and sliced into round or hexagon or wafers. Although this process is labor-intensive expensive and wasteful it produces the highest efficiency cells. Polycrystalline cells - ANSWER-These are made of molten silicone that is cast into ingots or drawn into sheets then sliced in squares Lower production cost but only 15% efficiency Amorphous silicon cells - ANSWER-Made up by spraying silicone onto a glass or metal surface in thin films The least expensive method but very low efficiency which is about 5% passive solar heating - ANSWER-the use of sunlight to heat buildings directly, The simplest in oldest method of using natural materials or absorptive Structures without moving parts together and hold heat example, stone and brick walls that gather heat during the day and lose it slowly at night geothermal energy - ANSWER-Earths heat, radioactive decay from within the planet. Cheaper and cleaner than many sources. How was geothermal energy captured - ANSWER-Geothermal springs for power plants