Energy from the sun


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Energy from the sun

  1. 1. Energy from the sun *twerp – huevón, tonto (informal English)
  2. 2. The enormous amount of energy emitted by the Sun is created by nuclear reactions in its core. This energy allows life in the Earth. The energy from the Sun is responsible for the water cycle and the geological agents that shape the landscape. Where does solar energy come from? Water cycle Sun
  3. 3. How does solar energy reach the Earth? Most of the energy from the Sun is absorbed by the atmosphere and warms the land and the sea. The energy which reaches the ground is mostly visible light.
  4. 4. Different parts of the Earth receive different amounts of solar radiation. This is because the Sun's rays strike the Earth's surface most directly at the equator. As you move away from the equator, you will notice that different areas also receive different amounts of sunlight in different seasons.
  5. 5. <ul><li>But what causes the seasons? </li></ul><ul><li>The Earth revolves around the Sun once each year and spins on its axis of rotation once each day.  </li></ul><ul><li>At the summer solstice, June 21 or 22 of each year, the Sun's rays are hit the Earth most directly along the Tropic of Cancer. When it is summer solstice in the Northern Hemisphere, it is winter solstice in the Southern Hemisphere. Winter solstice for the Northern Hemisphere happens on December 21 or 22. </li></ul><ul><li>When it is winter in the Northern Hemisphere, it is summer in the Southern Hemisphere. </li></ul>
  6. 6. Rays from the Sun reach the Earth at different angles: • Around the Equator: The rays from the Sun are almost perpendicular to the ground. Because of this, the air, ground and ocean waters are warm. • At the poles: The rays reach the Earth at an oblique angle. Consequently the ground, air and ocean water is not warm. As a result of this unequal heating of the Earth, air currents and ocean currents are created: • Warm air from the Equator moves towards the poles and cold air from the poles moves towards the Equator. • Warm ocean currents move from the Equator towards the poles and cold ocean currents generated at the poles move towards the Equator.
  7. 7. What are local atmospheric phenomena Thermals. These are columns of hot air which rise from the warm surface heated by the Sun. Storms . When there is a big difference in temperature between the warm air on the ground and the cold air at higher altitudes, big thunder clouds are developed. Coastal breezes . At the coast, the Sun warms the land and the sea, but the land heats up and cools down faster than the water.
  8. 8. Thermal inversions. Sometimes, the air at higher altitudes is warmer than the air near the ground. The air does not move. This cause, pollution from industries and traffic to be trapped near the ground.
  9. 9. What is meteorology? <ul><li>Meteorology is the science which studies the atmosphere and its phenomena, including weather and climate. </li></ul><ul><li>Weather : the state of the atmosphere, at a certain moment and in a certain area. That is to say, the temperature and other conditions such as sun, rain, and wind. </li></ul><ul><li>Climate : the typical weather conditions in a particular area. </li></ul><ul><li> For example, Los Angeles' warm, dry climate </li></ul>
  10. 10. So, weather and climate are meteorological terms that are related but not interchangeable. While weather defines the conditions of the atmosphere over a short period of time for example, a day or week, it is climate that defines the conditions of the atmosphere over longer periods like an entire year or decade. Climate Weather
  11. 11. On the weather maps they draw isobars. Isobars are lines which connect points of equal atmospheric pressure, measured in millibars. Weather maps help to make predictions about: • Wind : It is the movement of air. If there is a different temperature between two places, the pressure is also different (warm air = low pressure, and cold air = high pressure). Wind forms because air tends to move from high pressure areas to low pressure areas. • Clouds : Warm air rises, then cools and condenses. When vapour condenses, it forms clouds made up of tiny water droplets. When the clouds are near the ground, they form fog. • Precipitation : If the temperature descends sufficiently, water vapour condenses. When the microscopic water droplets expand and become heavy, they can form rain, snow or hail. Fog Rain Hail Snow Wind Cloud Temperature
  12. 12. <ul><li>Weather maps can also help make predictions about anticyclones and depressions. </li></ul><ul><li>Anticyclone : It is a high pressure area. </li></ul><ul><li>There is good weather in this area </li></ul><ul><li>(Letter H in weather maps). </li></ul>
  13. 13. <ul><li>Depression : It is a low pressure area. </li></ul><ul><li>There is bad weather in this area and </li></ul><ul><li>it usually causes rain. (Letter L in </li></ul><ul><li>weather maps). </li></ul>
  14. 14. How is solar energy used? <ul><li>The sun has produced energy for billions of years.  Solar energy is the sun’s rays (solar radiation) that reach the Earth. This energy can be converted into other forms of energy, such as heat and electricity. </li></ul><ul><li>Radiant energy from the sun has powered life on Earth for many millions of years and all living beings use solar energy in different ways: </li></ul><ul><ul><li>Plants, for example, use it during photosynthesis to produce organic material. </li></ul></ul><ul><ul><li>A lot of animals use it to warm their bodies. </li></ul></ul><ul><li>In the 1830s, the British astronomer John Herschel famously used a solar thermal collector box (a device that absorbs sunlight to collect heat) to cook food during an expedition to Africa. Today, people use the sun's energy for lots of things. </li></ul>
  15. 15. <ul><li>When converted to  thermal (or heat) energy , solar energy can be used to: </li></ul><ul><ul><li>Heat water — for use in homes, buildings, or swimming pools </li></ul></ul><ul><ul><li>Heat spaces — inside homes, greenhouses, and other buildings </li></ul></ul><ul><ul><li>Heat fluids — to high temperatures to operate a turbine to generate electricity </li></ul></ul>
  16. 16. <ul><li>Solar energy can be converted to electricity in two ways: </li></ul><ul><ul><li>Photovoltaic (PV devices) or “solar cells” change sunlight directly into electricity. Individual PV cells are grouped into panels and arrays of panels that can be used in a wide range of applications: calculator chargers and watch batteries, powers for homes… </li></ul></ul><ul><ul><li>Solar Thermal/Electric Power Plants  generate electricity by concentrating solar energy to heat a fluid and produce steam that is used to power a generator. </li></ul></ul> Solar calculator Solar charger Solar batteries
  17. 17. <ul><li>The main benefits of solar energy are: </li></ul><ul><li>1.  Solar energy is renewable. </li></ul><ul><li>2.  Solar energy is environmentally friendly </li></ul><ul><li>3.  Solar panels are extremely reliable. </li></ul><ul><li>4.  Solar cells make no noise while collecting energy. </li></ul><ul><li>5.  In the long run, solar electricity is cheaper than buying </li></ul><ul><li>it from the power company. </li></ul><ul><li>6.  There is a huge variety of solar panel systems available. </li></ul><ul><li>7.  You're not required to connect to the power grid. </li></ul><ul><li>8.  You can sell excess electricity. </li></ul><ul><li>9.  Most governments will provide some kind of tax credit or incentive for people purchasing solar energy systems. </li></ul><ul><li>10.  Solar technology is constantly improving. </li></ul><ul><li>Two limitations of solar energy are: </li></ul><ul><li>The amount of sunlight that arrives at the Earth's surface is not constant. It varies depending on location, time of day, time of year, and weather conditions. </li></ul><ul><li>A large surface area is required to collect the energy at a useful rate. </li></ul> Power grid lines Solar panels
  18. 18. What are the risks from solar energy? <ul><li>The atmosphere filters solar radiation. Dangerous x-rays and gamma rays are absorbed in the upper layers of the atmosphere. Harmful ultraviolet light is absorbed by the ozone in the ozonosphere. </li></ul><ul><li>Even though solar radiation is filtered by the atmosphere, solar energy involves two main risks: </li></ul><ul><li>• Damage to the ozonosphere. </li></ul><ul><ul><li>• The greenhouse effect and global warming. </li></ul></ul>
  19. 19. Damage to the ozonosphere : Some gases called CFCs interfering in the formation of ozone. Consequently ultraviolet light can reach the surface of the Earth more easily. As a result, exposure to the Sun is dangerous for human skin and the risk of suffering from skin cancer is growing.
  20. 20. The greenhouse effect refers to the solar energy which is trapped in the atmosphere by certain gases as carbon dioxide. Without these gases, heat would escape back into space,and the Earth would be too cold for life. However, due to increased concentration of greenhouse gases, more heat is retained in the atmosphere. As a result, the average temperature on Earth is increasing. This process is called global warming .
  21. 21. <ul><li>Small things we can do to help: </li></ul><ul><li>Walk, ride your bicycle, or take the bus instead of always going by car. </li></ul><ul><li>Don't waste electricity (turn off the lights, the radio, the TV and the computer when you're not using them). </li></ul><ul><li>Reduce, reuse or recycle all kinds of items, from soda pop cans to clothes, to save energy and raw materials. </li></ul><ul><li>Plant trees to help absorb excess CO2, and to provide shade and windbreaks to keep buildings at more even temperatures so they will require less energy for heating or cooling. </li></ul>How can we prevent the greenhouse effect? ride your bike reduce, reuse, recycle plant trees
  22. 22. http :// www.leonardo - / all - energy - sun http :// / cartoons / SOLAR%20ENERGY%20EARTH%20SUN%20TWERPS _23443 http :// / water / http :// /CPEP/ Chart_Pages /5.Plasmas/ SunLayers.html http :// /07aug/01849/en/ why - the_issues / index.html http :// / wiki / High_School_Earth_Science / Energy_in_the_Atmosphere http :// /2009/12/ convection.html http :// / topics / Thermal http :// / journal / evening - wind - clock / http :// /2011/09/ page /5/ http :// sb.westfordk12 . us / pages /6gweb/6gss/wtravel10/B/ bsai / index.html http :// kids / energy.cfm?page=solar_home - basics http :// /solar- energy - information /05-solar- panels.htm http :// /?10- Benefits - of -Solar- Energy&id=2154024 http :// / sp / Extincion.php http :// /Q/ How_are_we_to_prevent_the_greenhouse_effect References