MODULE 1:GADGETS WORK WONDERS (I)Chapter 2 Discovering Energy
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Chapter 2 Discovering Energy
2.1 What are the different forms of energy?
2.2 How can energy be converted from one form to another?
2.3 What are the differences between renewable and non-renewable energy?
2.4 How can energy be used responsibly?
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ObjectivesRecognise and give examples of
different forms of energy in everyday life (potential energy, kinetic energy, light energy, heat energy, electrical energy and sound energy)
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What is energy? Energy is the ability to
do work.
There are many forms of energy.
Examples are:(a) potential energy(b) kinetic energy(c) light energy(d) heat energy(e) electrical energy(f) sound energy
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Different forms of energy
light energy
kinetic energy
What is potential energy?Potential energy is stored energy.
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Different forms of Potential Energy
water at the top of a waterfall has gravitational potential energy
black petroleum contains useful chemical potential
energy
the stretched spring in astapler has elastic potential
energy
What is kinetic energy? Kinetic energy is the energy that moving objects
have.
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moving objects have kinetic energy
What is light energy?Light energy allows us to see things. Light energy also plays an important role of
helping plants make food through photosynthesis.
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light helps plants to make food and the table lamp provides light for
reading.
What is heat energy?Heat energy keeps us warm in a cold
environmentand helps us cook our food.
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Heat is needed to toast bread and for keeping warm beside a fireplace
What is electrical energy?Electrical energy is the
result of the movement of electrons in electrical conductors such as copper wires.
Electrical energy is a very useful and convenient form of energy used widely in our daily lives. It is useful because it can be converted easily to other forms of energy by using electrical appliances.
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Electric hob (converts electrical
energy to heat energy)
Light bulb(converts electrical
energy to light energy)
What is sound energy? Sound energy allows us to
hear and communicate.
Sound energy enables us to listen to our favourite music and hear warnings of danger.
Sound is produced by vibrating objects such as the speaker in an electronic alarm clock or a hand bell.
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Activity Book LinkActivity 2.1Discovering Energy
hand bell (convertskinetic energy to
sound energy)
electronic alarm clock (converts electrical energy
to sound energy)
Chapter 2 Discovering Energy
2.1 What are the different forms of energy?
2.2 How can energy be converted from one form to another?
2.3 What are the differences between renewable and non-renewable energy?
2.4 How can energy be used responsibly?
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ObjectivesInvestigate energy conversion
from one form to another
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Law of Conservation of EnergyEnergy cannot be created or destroyed.
It can only be converted from one form to another.
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shooting an arrow with a bow converts
elastic potential energy to
kinetic energy
a wind generator produces electricity
from the kinetic energy of wind
using an electric bulb converts
electrical energy to light
energy
Useful energy conversions
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using batteries as a source of electricity converts chemical
potential energy toelectrical energy
fossil fuels contain chemical energy which can be
converted toelectrical energy
audio-visualequipment converts electrical energy to
sound and light energy
Harmful energy conversions
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a nuclear explosion converts nuclear
energy to heat energy
overheating of wires can cause fire as electrical energy is converted to heat
energy
loud noises from jackhammer can
causehearing loss as
kinetic energy is converted to sound
energy
Activity Book LinkActivity 2.2Steam Engine Model
Chapter 2 Discovering Energy
2.1 What are the different forms of energy?
2.2 How can energy be converted from one form to another?
2.3 What are the differences between renewable and non-renewable energy?
2.4 How can energy be used responsibly?
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ObjectivesCompare the differences between
renewable energy (solar, wind, biomass, hydro) and non-renewable energy (coal, oil and natural gas), and their limitations
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Sources of energy Sources of energy can be broadly
classified into renewable or non-renewable
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Non-Renewable Sources of EnergyNon-renewable sources of energy are
limited and will run out one day. Most non-renewable sources of energy are obtained from fossil fuels.
The three main types of fossil fuels are:(a) crude oil (also known as petroleum),(b) coal, and(c) natural gas.
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Fossil fuelsFossil fuels are a form
of non-renewable energy.
While it takes millions of years for fossil fuels to form, it takes only a short time to burn them.
There will come a day when fossil fuels run out.
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diesel and petrol are used as fuels for motor vehicles
Problems with using fossil fuels
Burning of fossil fuels releases carbon dioxide into the air which is a greenhouse gas that causes global warming and climate change.
Extraction of fossil fuels can ruin landscapes.
Mining of fossil fuels can cause death and injury to workers.
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freshly mined coal
Natural gas
Natural gas is made up of mainly methane gas.
It is used in power stations in Singapore to generate electricity and also for cooking at home.
There are also motor vehicles which are powered by compressed natural gas (CNG).
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car running on Compressed Natural Gas (or CNG) fuel.
Natural gas
Compared to other fossil fuels, natural gas is considered a clean fuel.
Natural gas can be transported over long distances using pipelines and large tanker ships as it can be compressed into a liquid.
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natural gas is used for cooking
Renewable Sources of Energy
Renewable sources of energy come from natural resources such as wind, sunlight, water and plants.
Renewable sources of energy can be used again. They help to reduce the use of fossil fuels.
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The “Supertrees” at Gardens by the Bay are installed with solar
panels
Renewable Sources of EnergyMost renewable
sources of energy do not cause air pollution or release greenhouse gases into the air.
Examples of renewable sources of energy are wind energy, solar energy, biomass and hydropower.
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the Hoover Dam generates hydroelectric power
Wind EnergyWind is moving air which
has kinetic energy.
Wind turbines convert the kinetic energy of the wind into electricity.
Once the wind turbines are built, the energy obtained is effectively free.
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kinetic energy of wind canbe converted into electrical
energyby using wind turbines
Wind Energy Wind energy is clean and does
not produce greenhouse gases.
Wind energy will not run out.
The amount of electricity that can be produced depends on the strength of the wind so wind turbines are built only in places with strong winds most days of the year.
The wind in Singapore is usually gentle, so wind energy is not used here.
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The wind farms in Palm Springs, California , are built along hilly
areas
Solar EnergySolar energy is
energy from the Sun.
Solar panels convert solar energy into electricity.
Solar energy is clean, free and will not run out.
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solar panel mounted on a street lamp
Solar Energy
Solar energy is suitable for places with lots of sunlight throughout the year. This makes it suitable for Singapore which has an average of 12 hours of sunlight per day throughout the year.
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solar panels mounted on rooftops in Singapore
Hydropower
Hydropower refers to the energy obtained from flowing water.
A dam is built to block a river. The water behind the dam is then used to turn water turbines. The water turbines then turn generators to produce electricity.
As Singapore does not have big rivers with high water flow, we are not able to use hydropower as a source of energy.
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a hydroelectric power plant
Hydropower Hydropower does not
produce any pollutants or greenhouse gases.
Once the dam is built, electricity can be generated as long as there is water flow.
However, dams are very expensive to build and can cause large areas of land upstream to be flooded.
The ecosystem and habitats of some animals can be destroyed due to flooding.
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Three Gorges Dam in China
Comparing Renewable and Non-Renewable Sources of Energy
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Activity Book LinkActivity 2.3 Sources of Energy
Chapter 2 Discovering Energy
2.1 What are the different forms of energy?
2.2 How can energy be converted from one form to another?
2.3 What are the differences between renewable and non-renewable energy?
2.4 How can energy be used responsibly?
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ObjectivesAppreciate that fossil fuels are
exhaustible and the need and ways to reduce energy wastage
Appreciate the importance of conserving energy in our daily lives because Singapore is dependent on imported fossil fuels to meet its energy needs.
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Why should we reduce energy wastage?
We should reduce energy wastage as fossil fuels cannot be replaced and burning fossil fuels causes pollution problems.
Singapore depends heavily on imported fuels such as oil and natural gas from other countries for our power stations and vehicles to use.
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how can we conserve the use of electricity at home?
Using energy responsibly It is urgent and important for us
to use energy responsibly and to encourage the use of renewable sources of energy.
Our government is also encouraging the use of energy-saving technology and providing money to research on clean energy.
An example is the Carbon Emissions-based Vehicle Scheme (CEVS) where buyers of cars with low carbon emission will enjoy rebates
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hybrid car with low carbon emission
How can we conserve energy?
We can do our part to conserve the use of energy by:
(a) using only the amount of energy needed;(b) developing the habit of saving energy;(c) taking public transport;(d) sharing this message of conserving energy with our family and friends.
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Project Carbon Zero is an energy-saving competition
project organised by NEA and SEC for school students to
motivate them to reduce energy wastage at home
Picture referencesWind turbineshttp://www.doorsofperception.co
m/infrastructure-design/could-green-energy-kill-the-desert-2/
Solar panels on rooftopshttp://oliveventures.com.sg/act/2
012/11/14/solar-panel-leasing-in-singapore-yes-please/
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