Review
Electricity can be generated in many ways. Static electricity causes object to attract one another. Is called static because it builds up on object and does not move. Current electricity flows through wires.
Measuring electrical energy: -The energy consumed by a device is measured in kilowatt/hours.
Electrical appliances use different amount of electricity. POWER refers to how much electrical energy is required to run an appliance for one second and is measured in watts. Energy usage is usually measured in kilowatts/hours and is found by multiplying the power rating of an appliance by the amount of time that the appliance is used.
Kilowatt hour: a measure of electrical energy (equal to 1000 watts being consumed for 1 hour). Power: the rate at which a device uses electrical energy (expressed in watts). Watt: a measure of the rate or energy consumption.
Photosynthesis: the process by which green plants, algae, and some bacteria use light energy, wáter and carbón dioxide to make sugars that they use for food. Cellular respiration: The process by which the energy stored in sugars is released for use by the cells of organisms.
Plants convert energy from the sun into the chemical energy in food. Animals get energy be eating plants or other animals. When plant and animals die, they become food for organism such as bacteria and fungi.
Reactant of photosyntheis: carbon dioxide and water. Products of photosynthesis, oxygen and sugar. Reactant of cellular respiration: sugars and oxygen. Products of cellular respiration: water and carbon dioxide. (Review the chemical equation of both processes; photosynthesis and cellular respiration).
Producers convert energy from the sun into chemical energy through photosynthesis. – All organisms release this energy through cellular respiration and use the energy for life processes. – energy is passed through food chains from producers to consumers.
It is possible to calculate how much energy it takes to run an appliance by multiplying the estimated number of hours it is used by its power rating. (review The Kilowatt Kids Investigate 348-349. practice exercises).
How to read a electricity meter: dials are read from left to right. Each dial represents a digit in a four digit number. The four digit number is then multiply by 10 to provide the correct number of kilowatt-hour, pointers that fall between two numbers of a dial are read as the lower of the two numbers. (practice exercise. reading a electricity meter and finding the energy consumption per month).
Most of the energy used today comes from fossil fuels, which are in limited supply. Saving energy not only saves money, bu also preserves valuable natural resources.
Energy sources and usage today are very different from those in the past. – In the last 100 years, energy use has increased dramatically.
When was the light bulb invented?? For whom? 1879 Thomas Edison. The California Electric light company begins operating the first commercial power plant to sell electricity to private customers.
When was the beginning of the automobile age? 1908. Henry Ford. Demand for petroleum.
Why do you think energy usage has increased so dramatically since 1950? The population has increased and consumers have purchased and used more energy consuming goods, such as cars, and electrical appliances.
Energy sources that can be replaced are called renewable; those that cannot are called nonrenewable. The supply of oil and other nonrenewable energy sources is running out.
Renewable resources: energy sources that can be replaced naturally, such as wood, wind, hydroelectricity, and solar energy.
Nonrenewable resources: energy sources that cannot be replaced once they are used up, such as oil, natural gas, uranium, and coal.
What is black gold? Crude oil.
What would happen without oil? What is provides? Uses of petrochemicals, Our civilization would collapse, oil makes our industrial world go around. Provides energy for factories, heat for homes, gasoline for cars, petrochemicals make plastic, paints, fibers, medicines.
What is happening with the demand and supply of oil? Demand for oil is increasing, but the supply is running out.
Other sources of energy: coal, hydroelectricity, wind, garbage, oil, sun, wood, nuclear, and natural gas.
1. Make a plan for saving energy (electricity)
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