P2 - Living for the Future
- Created by: bethblackburn99
- Created on: 03-05-15 14:03
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Using the Sun's Energy
- Sun gives out energy in the form of heat and light, some of this energy is stored as fossil fuels.
Photocells (solar cells)
- Generate electricity directly from sunlight
- Generate direct currect (DC)
- Direct Current - current flows the same way around the circuit all the time
Usually made of silicon (semiconductor). When sunlight falls on the cell:
- Silicon atoms absorb some of the energy, releasing some electrons
- These electrons then flow round in a circuit, which is electricity
The current and power output of a photocell depends on:
- Surface area (bigger the cells, more electricity produced)
- Intensity of light (brighter, more electricity)
- Distance from light source (closer the cell, more intense the light hitting it will be)
Advantages:
- No moving parts - sturdy, low maintenance, last a long time
- Don't need power cables/fuel
- Renewable, doesn't pollute
Disadvantages:
- No sunlight, no power
- Not useful at night or when weather is bad
Solar and Wind Power
Passive Solar Heating
- Passive Solar Heating - when energy from the Sun is used to heat something directly
- Light from the Sun has a short wavelength - pass through glass into a room, but the heated things in a room emit infrared radiation from a longer wavelength (can't escape through glass) reflects back, just like the greenhouse effect
Wind Turbines
- Energy from the Sun heats the atmosphere which causes convection currents, which produce wind
- Wind turbines convert the kinetic energy of moving air into electricity
- Wind turns the blades, which turn a generator
Advantages:
- Cheap to run, tough and reliable, wind is free
- No pollution
- Wind power - renewable
Disadvantages:
- Wind farms - visual pollution (spoil views)
- Spinning blades - noise pollution
- Wind isn't fast enough to generate power
Producting and Distributing Electricity
National Grid
- It is the network of pylons and cables
- It takes electricity from power stations to where its needed - homes and industry
- It enables power to be generated and supplied anywhere on the Grid
Power Stations
- STAGE 1 - use the fuel to produce heat which then generates steam (job of the boiler)
- STAGE 2 - moving steam drives the blades of a turbine
- STAGE 3 - rotating movement from the turbine is converted to electricity by the generator (using electromagnetic induction)
IN A TABLE
Type of Power Source :Fossil Fuels
Advantages
- Readily available
- Concentrated solute of energy (little bits of coal gives out alot of heat)
Disadvantages
- Burning them - acid rain
- Produces carbon dioxide
Type of Power Source: Biomass
Advantages
- Renewable
- Carbon neutral
Disadvantages
- Need alot of biomass to replace on lump of coal
- Takes alot of room to grow
The Dynamo Effect
- Electromagnetic Induction (EM) - the creation of a voltage (and maybe current) in a wire which is experiencing a change in magnetic field
- Dynamo Effect - when you use electromagnetic radiation to transform kinetic energy into electrical energy
Two different situations where you get EM induction:
- Electrical conductor (coil wire is often used) moves through a magnetic field
- Magnetic field through…
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