Unit: Energy and Control- Electricity

 Niagara Falls is more than just a scenic place. The famous waterfall is also home to Ontario’s first hydroelectric generating station. And just north of the falls are two more huge generating stations, one in Ontario and one in New York. The generating stations at Niagara Falls are only two of Ontario’s 68 hydroelectric generating stations. Although we have access to a lot of electricity, it is important to use electricity wisely.

 Look back at your list from Investigation 2. Draw a table, similar to the one on the right, in your notebook. Under “electric device,” list 10 devices in your home that you think use the most electricity.  Find out which device in your home actually uses the most electricity in one day. To find out how much power a device uses, look for the power rating on the CSA (Canadian Standards Association) sticker. The amount of power is measured in watts (W).

Electric deviceWattageHours used in one day Watt hoursKilowatt Hours/ Day (kWh) Kitchen light100 W

 We are billed for our power use in kilowatt hours (kWh). Using a calculator, multiply the wattage of the appliance by the number of hours you use it in a day. Divide the number by Your answer is the amount of electricity the device uses in a day in kilowatt hours.

 Calculate the energy use of these ten appliances for one day. Keep a record of how long each one was turned on. Multiply their wattage by the number of hours they were used. Write down the answer in the fourth column of the chart. Which device actually used the most electricity in one day?

 Think of some ways to save electricity in your home and develop a plan. Some ways of saving electricity are behavioral, such as remembering to switch off the light when you leave a room. Other ways are physical, such as using lights that need less power, i.e., have a lower wattage.

 There are many ways to save electricity. What are some of the positive effects of saving electricity? Don’t forget where electricity comes from. Some devices that help conserve electricity cost more money to buy, but save money over the time they are used. For example, an ordinary light bulb may use 60 watts of electricity. An energy-conserving fluorescent light bulb that gives the same amount of light only uses 13 watts of electricity, but costs more money to buy. However, it saves money because it uses less power and lasts longer than the ordinary light bulb

 Describe the plan you have developed to save electricity in your home.  Present your plan to the class.

 Today, there are many ways to produce electricity (as we have learned in previous lessons). Electricity generation from fossil fuels causes air pollution. Coal, oil, and natural gas are non-renewable sources of energy and will eventually run out. In most areas, generating stations that burn fossil fuels are used to meet “peak” electricity demands, i.e., during the day when people use more power

 Coal, oil, or natural gas is burned to boil water. The resulting steam is passed through a turbine which turns a generator which produces electricity. It is a modern variation of the steam engine invented over 200 years ago. The main by-products of burning coal and natural gas are carbon dioxide, nitrous oxide, and sulfur dioxide. These, along with elements such as arsenic, mercury, and cadmium, are released into the air and contribute to acid rain and photochemical smog.

 In a nuclear reactor, uranium, a non- renewable resource, is the fuel. The energy of the uranium atom is harnessed in a process called nuclear fission. When a uranium atom is split, a lot of energy is released. This energy is converted to heat which is used to make steam. The steam turns a turbine which turns a generator, which produces electricity.

 Electricity generated from nuclear energy has the potential of being extremely dangerous. While there has never been a nuclear disaster in Canada, in 1986 the Chernobyl reactor in the former Soviet Union suffered a serious nuclear disaster, a meltdown. The surrounding area was badly affected from radiation and a lot of people died.

 Hydroelectricity is electricity from falling water. Ontario Power Generation’s first hydroelectric generation station was Niagara Falls, and one is still there today. Hydroelectricity is a renewable resource. There is no pollution.  Most hydroelectricity comes from generating stations located near a dam. These dams can last a long time. When a hydroelectric dam is build, however, a lot of land is flooded to create a reservoir. This changes wildlife habitat and displaces people. Also, most hydroelectric dams are a long distance from cities, so electric wires must be run long distances.

 Electricity from the wind and from the sun is renewable and non-polluting. Yet in most areas only a tiny fraction of electricity is produced this way. The main disadvantage of solar power and wind power is that the sun does not shine all the time and the wind does not blow all the time. A method of storing the electricity must be included in the design. The cost of these sources of electricity is far higher than conventional sources. But this may change in the future.