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1.
Provincia
Marista
Mediterránea
Colegio
“La
Sagrada
Familia”
UNIT 8: ENERGY
- gives us light, sound and heat.
Energy - makes things move.
- powers machine.
- most of it comes from the Sun.
Six forms: - natural sources (stars) or artificial (light bulbs and torches).
- fastest form of energy (300.000 km/s).
*LIGHT - made up of seven different colours.
- it allows us to see shapes, colours and sizes.
- it always travels in a straight line.
(exepction  light can be absorbed, reflected or refracted.
- released when a chemical reaction occurs.
*CHEMICAL - car burns petrol  chemical reaction  chemical energy
transformed into kinetic energy.
- more examples: batteries and food.
- is a vibration that can travel in any direction from the source.
- large vibrations loud sounds.
*SOUND - smal vibrations  soft sounds.
- can travel through gases, liquids, solids but not through vaccum.
- all moving things have it.
*KINETIC - the heavier and obtejct is, the faster it moves and the more kinetic
energy it has.
- E.g.: moving car, windsurfer, bike in movement.
- used to power machines.
*ELECTRICAL - can be transformed into light, sound, heat and movement.
- sources: burning fossil fuels/ sunlight, wind, water and biomass/
nuclear power stations.
- it flows from a warm substance to a cooler substance.
(this flow is called heat)
*THERMAL
- sources: the Sun/fossil fuels (warm our houses, cook food)

2.
Provincia
Marista
Mediterránea
Colegio
“La
Sagrada
Familia”
UNIT 8: ENERGY
RENEWABLE ENERGY SOURCES (can be replaced)
- doesn´t pollute.
*SOLAR EN.
- solar panels are used.
- clean.
*WIND EN. - only in windy places.
- wind turbines are used - can damage habitats.
- can kill birds.
- doesn´t pollute.
*WATER EN. -damage habitats.
- dams
- cause biodiversity loss.
- organic material derived from living things (wood, dried vegetation, food
waste)
*BIOMASS - biomass is burned  steam produced turns a turbine  electricity.
- causes air pollution.
- heat produced by the decomposition of underground radioactive
substances
*GEOTHERMAL EN. - doesn´t pollute.
- limited to certain geographic areas.

3.
Provincia
Marista
Mediterránea
Colegio
“La
Sagrada
Familia”
UNIT 8: ENERGY
NON-RENEWABLE ENERGY SOURCES (limited)
*FOSSIL FUELS: decomposed organic material that has been deep underground for millions
of years.
- pollutes.
- COAL
- produces lots of energy.
- oil spills can cause ecological disasters.
- OIL
- easy to transport and store
- NATURAL GAS
- nuclear power stations use a radioactive metal to generate electricity.
*URANIUM - we have enough to generate electricity for many centuries.
are expensive.
- stations
produce radioactive waste products (can cause cancer).

4.
Provincia
Marista
Mediterránea
Colegio
“La
Sagrada
Familia”
UNIT 8: ENERGY
ELECTRICITY
Objects have electrical charges. They can be positive or negative charges.
- conductors (copper, aluminium).
Materials can be electrical
- insulators (wood, rubber, cotton, plastic).
- current  it´s when an electrical charge moves (flow) in an
electrical conductor.
Two types of electricity
- static  it´s a form of electricity that doesn´t flow (lightning,
hair after brushing it)
MAGNETISM
A magnet is an object which can attract certain metals (iron, steel…). They can be natural
(magnetite) or man-made.
Magnets have two poles: north pole and south pole.
N&N
repel S&N  attract
S&S