Light Up My Life |
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Activity Summaries |
Physics Principles |
Activity One: The Inverse Square Law Students consider kinds of light sources used through history to overcome darkness. Students measure illuminance as a function of distance from a candle and an electric lamp as a basis for deriving the inverse square law. |
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Activity Two: The Right Amount of Light Students measure illuminance in their classroom and school and compare measured values to illuminance standards used by lighting professionals. |
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Activity Three: Light and Color Students use a spectrometer to observe and measure wavelengths of colors within the continuous visible spectrum. The effects of color filters on light are observed. Human color vision is explained as analogous to mixing colors of light. The electromagnetic spectrum is introduced. |
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Activity Four: Light from Lamps A spectrometer is used to compare light emitted from an incandescent lamp, gas discharge tubes and a fluorescent lamp. The bright line emission spectrum of an element is established as a unique "fingerprint." The efficacy of an electric lamp, analogous to efficiency, is defined. Students survey kinds of electric lamps used in the community and describe how the light output of each kind of lamp affects the perceived color of objects. Electric lamp technology is summarized. |
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Activity Five: Measuring Light Quality: Color Characteristics Students observe that the quality of light emitted from electric lamps varies with the kind of lamp. Correlated-Color Temperature and Color-Rendering Index are introduced as measures of color characteristics of light from lamps. Students learn how lighting designers may use color characteristics of lamps to establish desired psychological effects or moods in chosen environments. |
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Activity Six: The Quality of the Visual Environment Criteria used by professionals for designing lighting systems are applied by students to their science classroom. Students analyze lighting design suggestions posted on the web site of the Illuminating Engineering Society of North America for locations and tasks similar to the design situation they have chosen for the Chapter Challenge. Specific design criteria that apply to students' design problems are identified. |
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Activity Seven: The Light Bill Students analyze typical residential electric bills. The basic charge on a bill is understood as the multiplication of energy used (kWh) and rate charged ($/kWh). Students learn how to predict the energy consumed by an electric lamp or appliance ' and the cost of operating the device ' using the power rating, estimated operating time and rate charge. |
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Activity Eight: Ways to Save Energy and Money on Lighting Advantages of recently developed high efficacy lamps is demonstrated as students compare the energy consumption and operating cost of traditional incandescent light bulbs to compact fluorescent bulbs. Many ways of reducing energy consumption and operating costs of lighting systems in residences and large buildings are also explored. |
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Activity Nine: The Economics of Lighting Students are guided to develop a computer spreadsheet that allows them to compare the performance of any two light bulbs in terms of initial cost, energy consumption and operating cost over several life cycles of the bulbs. When a modern compact-fluorescent bulb is compared to a traditional incandescent bulb of equal light output, the payback period and return on the initial investment are apparent. The spreadsheet could be applied equally well to compare electrical appliances. |
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