Slide 1

Allen High School IB Physics SL Source: Chris Hamper Physics Slide 2 Solar Hydroelectric Wind Wave This is the future of energy! Lets take a closer look.... Slide 3 The Sun emits 3.90 x 10 26 J of energy PER SECOND! The energy spreads out and by the time it reaches Earth (radius = 1.5 x 10 11 m), the Suns power is less intense. Power per unit area 3.90 x 10 26 = 1380 W/m 2 -- This is the Solar 4 (1.5 x 10 11 ) 2 Constant The Suns energy is either absorbed or reflected. We use the Suns energy to either heat something or to make electricity. Slide 4 The amount of energy that reaches surface of the Earth depends on how much atmosphere it has to travel through. Intensity depends on Latitude. The Sun shines through the least amount of atmosphere (most intense) when it is directly above (most atmosphere at sunset and sunrise = least intense). Intensity also depends on the season; at different times of the year, since the tilt of the Earth varies throughout the year. Slide 5 Solar Heating Panel These are found on roofs of houses/buildings. Solar radiation is absorbed by the panels black metal plate, which then warms water by conduction. The warm water is then circulated. Photovoltaic Cell (Solar Cell) Converts solar energy into electrical energy. Similar to a batterys conversion of energy, except instead of chemical energy, its solar energy. The potential difference & current produced by one cell is small, therefore many cells are connected together. Slide 6 In a previous presentation, you learned that hydroelectric power originates with the Sun warming oceans; evaporation; clouds condensing; and then the rain falling has a high PE. Note that height (in PE = mgh) would be the average height of the water. This process can produce electricity. Dams store energy in the form of water. Electricity is produced via generator when the water is released. (See picture on next slide) Slide 7 Slide 8 Windmills have been around for a while for a variety of purposes. Nowadays, we use them to generate electricity. You learned previously that wind is caused by the Sun. The flow of warm air creates areas of different pressure, causing air to move = wind. The rotation of the Earth causes this wind to move in circular patterns. Slide 9 Coastal winds are caused due to different rates of heating of the land/sea. We learned previously that water has a high specific heat and warms in day and releases at night. This air movement is wind. Katabatic winds are formed when a high pressure is caused by cold air pressing down at the top of a mountain, resulting in a downhill airflow. Slide 10 Slide 11 Waves crashing ashore = energy transfer There are surface waves (small) or rolling waves (originate out in ocean). The energy of a wave alternates between PE as the water is lifted up and the KE as it falls. This method is (as are the others) limited to the supply of waves consistently. Slide 12 A column half full of water. As water flows in, it compresses the air above pushing it through a turbine, which (if you havent guessed by now) generates electricity. The turbine is specially designed so that as the water drops back down the column, the turbine also turns as it pulls air into the chamber. Slide 13 Slide 14 Renewable resources are usually nontraditional and more expensive in the beginning, but their benefits can have long- term effects. The challenge of the future = Make non-traditional the new traditional!