electrical charge flows from the base to a coiled wire filament made of tungsten, which gets so hot it gives off light
what are the pros and cons of incandescent bulbs?
pros- cheaper, not toxic. cons- lasts only 1,000 hours, wastes light energy on heat, linked with greenhouse gas emissions
how does a Compact Fluorescent Lightbulb work?
contains a gas-filled tube and a magnetic ballast. Electric current flows through them, gases emit UV light, which energizes a phosphor that coats the tube, which emits light
what are the pros and cons of CFLs?
pros- 10,000 hours of life, uses up to 80% less energy, 75% less heat than incandescent bulbs. cons- more expensive upfront, but you save in the long run
what happens as energy demands increase?
price goes up
why is insulation important for your house?
it keeps heat inside your house, so you don't have to use as much energy to keep your house warm
how do you affect the Earth's climate?
driving, eating, cooking, needing light
how does color affect absorptivity?
light is made of all the colors of the rainbow, so when it hits an object, all the colors will be absorbed or reflected. Black absorbs all the colors because it contains no color, and white reflects all colors because it is all of the colors combined.
how can photovoltaic cells be used to produce electricity?
solar cells have layers of boron (positive) and a layer of phosphorous (negative), which sit in a coating of silicon. When sunlight hits the cell, it initiates a flow of electrons from the negative to the postive layer, creating electricity
what is the process of hydraulic fracturing?
fractures in the earth are created by pumping lots of fluids at high pressure into the ground. The fluid contains water, sand and gravel; and chemicals. The sand and gravel keeps open the fissures, which can contain oil. Fracking can reach down more than 1 mile, which is when it reaches natural gas. When the gas is fracked it floats up through the fracking hole to the wellbore. After injection, internal pressure causes fluid to return to the wellbore, and it is stored on site before treatment.