photocells (solar
cells) generate
electricity directly
from sunlight
they generate
DC (direct
current)
made of silicon, the
atoms absorb some
of the energy,
knocking loos some
electrons, these then
flow round a circuit
the current and
power output of a
photocell depends
on: surface area,
intensity of light,
the distance from
light source
solar and wind power
passive solar heating
wind farms
wind is a renewable source
wind turbines are cheap
to run, no polluting
waste, renewable
1500 turbines replace 1 coal
fired power station, visual
pllution (ruin view), wind can
not be fast enough, blades
make noise (noise pollution),
impossible to increase suply
when demand, expensive to
set up, hard to find
somewhere
power stations
fuel, boiler,
steam,
turbine,
generator,
national grid
fossil fuels
biomass
nuclear power
photcells
wind power
electromagnetic
the creating of a voltage and maybe current
in a wire which is experiencing a change in
magnetic field
greenhouse effect
carbon dioxide
cars, fossil fuels,
chopping/burning trees
Methane
cattle,
volcanoes,
wetlands
water vapour
alpha, beta, gamma
alpha particles are big and
heavy and are stopped by a
sheet of paper
beta particles are
electrons, stopped by
aluminium
gamma rays are very high frequency
electromagnetic waves, thick lead stops
gamma