Thermal power stations and hydroelectric power stations are two examples of electrical energy producers discussed. In a thermal power station, chemical energy from fuel is converted to heat energy via combustion, which then boils water to create steam and drive turbines to generate electricity. In a hydroelectric station, gravitational potential energy of elevated water is converted to kinetic energy as it flows through turbines to also generate electricity. Both examples demonstrate energy transformations through energy chains from one form to another.

2. Chemical reactions and
Energy Part 2

3. Remember?
Potential and
kinetic energy

Changes caused by different forms of
energy. We can understand energy as the
ability of something to cause change. We
can then classify energy changes
according to the forms the energy takes,
and then show the energy changes in the
form of an energy chain.
Let´s see how it works with examples of
electrical energy producers.
something to cause change.WE can
changes according to the forms the energy
takes, and then show the energy changes in the form of an energy chain.

4. Thermal power station

5. Energy
producer,
Thermal
power station,
Thermal-heat
recovery
 In a thermal power station the energy is obtained form a
fuel-usually a fossil fuel such as coal, oil or gas.The
energy stored in the fuel is released through combustion
or burning, which turns it into heat.This heat is then used
to boil water and make steam, which is produced under
high pressure.The molecules of water in the steam then
have large kinetic energies, which mean they move very
rapidly and can be used to drive a large turbine, so
transferring the kinetic energy of the water molecules
into kinetic energy in the machinery.The machinery is
then used to drive electrical generators which use
magnetic fields to make electrons in conductor wires
move –which is electricity.
An Energy Chain ofThermal power station
Chemical energy (fuel, potential energy stored in
fuel)----heat energy (combustion)-----mechanical
energy (turbines)-----electrical energy

6. Hydroelectric
power

7. Hydroelectric
power
 In a hydroelectric power station, energy is
stored in water (potential energy) that is held
high in a reservoir, such as in a mountainous
area.The potential energy stored in the
water is then changed into kinetic energy
when the water is released to fall through
turbines.
An energy chain
Potential energy (gravitational)……kinetic
energy (water)……mechanical energy
(turbine)……electrical energy

8. Challenge 1
Research:
Energy
(Upload it on
Manage bac)
Energy from nature:
Research:The systems of
hydroelectric dam, wind turbines,
photovoltaic solar panels,
geothermal power

9. Challenge 2
Read the
following the text
about yogurt and
make a mind
map.Also you
have to answer
these questions.
(Upload it on
Manage bac)
 Yoghurt is produced by fermenting milk. All types of milk can be used,
from cow´s to camel´s milk.The milk is first heated to kill any unwanted
bacteria and then the fermenting culture is added.This culture is a special
type of bacteria which ferments milk.The mixture is then kept at a
constant temperature of about 45º Celsius.The process of fermentation
converts the liquid milk to semi-solid state. It also gives yoghurt its
characteristic tangy taste.Yoghurt can be stored for a longer period than
fresh milk.Yoghurt is usually made in factories, but it can easily be made at
home.
 Questions:
 Is it made all over the world?
 Does it need oxygen?
 Does it need to be kept warm?
 Does it change state?
 Does it need special apparatus?
 Are only certain bacteria used?