Energy
Singapore is a clean and green city. Today, we have more green
buildingsanduseenergy-savingappliances.Weshouldcontinueto
playourparttocarefortheenvironmentandconserveresources.
Greenbuildings
Have you ever heard of green buildings?
Theyarebuildingsthatuselessenergy.
The National Library Building is one of the
manygreenbuildingsinSingapore.Itsaves
energy in a number of ways. There are
daylight sensors that turn window blindsto
reducetheglareoftheSun.Theblindsalso
helptopreventthebuildingfrombecoming
too hot due to the Sun, reducing the use
of air conditioning. Movement sensors on
escalators and energy-efficient lightings
alsocutdowntheuseofelectricity.
The plants in the roof garden and sky
terracescoolthesurroundingair.Thishelps
tofurtherreducetheuseofairconditioning.
What are other
ways of conserving
energy?
The National Library Building has
many energy-saving features.
iv
Energy
01_(S)MPaH_Ene5&6 TB(Std)_Front matter.indd 4
8/26/15 2:14 PM
Usingvegetableoiltomovecars
Vegetableoilisoftenthrownawayafteritisusedtocookfood.However,this
oil still has energy in it. Instead of being thrown away, the used oil can be
collected and converted to fuel. This fuel is called biodiesel. It can provide
energytomovecars,motorcyclesandtrucks.
Unlike fuels such as coal, biodiesel can be continuously produced from
plants.
What energy
changes take place
when cars run on
biodiesel?
Biodiesel can be made
from used cooking oil.
Energyisfoundeverywhere.Asyoureadmoreaboutenergy
inthefollowingchapters,thinkabouthowenergyisinvolvedin
everythingthattakesplacearoundyou.Askyourself:
• Whyisenergyimportanttous?
• Howisenergyusedineverydaylife?
• Whyisitimportanttoconserveenergy?
Usethisbooktoexplorethedifferenttypesofenergy,where
theycomefrom,howtheyareusefulandhowenergycanbe
conserved.
Theme opener
01_(S)MPaH_Ene5&6 TB(Std)_Front matter.indd 1
1
8/26/15 2:14 PM
1
•
•
•
•
Energy in food
Why do we need food?
How do plants make their own food?
How do animals obtain energy?
Why is the Sun important to living things on the Earth?
What does a person
need to stay alive?
Whenanaturaldisasterstrikes,peoplesometimeslosetheir
homes.Helpmustquicklyreachthesurvivorstoprovidethem
withtheirbasicneedssothattheycanlive.
Whydopeopleneedfoodtostayalive?
Do plants need food? If plants do not eat, how do they get
theirfood?
2
Energy
02_(S)MPaH_Ene5&6 TB(Std)_01.indd 2
8/26/15 2:21 PM
Why do we need food?
Weeatwhenwearehungry.Weneedfoodtostayalive.
Foodgivesustheenergythatweneedforactivitiessuchas
breathing,movingandgrowing.Whenwearemoreactive,we
needmoreenergy.
Do we need energy when we
are resting or sleeping? Why?
Weeatavarietyoffoodforenergy.Forexample,weeatplants
and animals. Our food also includes products of plants and
animalssuchasbreadandmilk.
Besides energy, food also
gives us nutrients such as
minerals and vitamins.
Eating a variety of food is
important for us to stay
healthy.
We get energy from a variety of food.
All living things get energy from food. Plants and animals
obtainfoodindifferentways.
Workbook activity 1.1
Energy in food
02_(S)MPaH_Ene5&6 TB(Std)_01.indd 3
3
8/26/15 2:21 PM
How do plants make their own food?
Plants make their own food using light, carbon dioxide and
water.Thisprocessiscalledphotosynthesis.
Plantscanmakefoodbecausetheyhaveagreensubstance
called chlorophyll. Chlorophyll is found mostly in the leaves.
Itisfoundinthechloroplastsofplantcells.
sunlight
Lightistrappedby
chlorophyllintheleaves.
How do plants get
their food?
Chlorophyll
is found in the
chloroplasts of
a leaf.
You will learn about how water
and food are transported to
various parts of a plant in the
theme of Systems.
4
Waterisabsorbed
bytherootsand
transportedtothe
leavesandother
partsoftheplant.
Energy
02_(S)MPaH_Ene5&6 TB(Std)_01.indd 4
8/26/15 2:21 PM
Chlorophyll traps light to enable plants to make food.
Thefoodwhichplantsmakeissugar.Sugarproducedinthe
leavesistransportedtootherpartsoftheplantssuchasthe
roots and flowers. The amount of sugar produced depends
on the amount of light, carbon dioxide and water that the
plantsget.
carbondioxide+water
light
sugar+oxygen
Carbondioxideistakenin
bytheplantthroughtiny
openingsonitsleaves.
Sugarisproducedinthe
leavesandtransportedto
otherpartsoftheplant.
Oxygenisalsoproduced
duringphotosynthesis.Itis
givenoutbytheplantthrough
thetinyopeningsonitsleaves.
tiny openings
What are the factors
that can affect the rate
of photosynthesis?
How are the products
of photosynthesis
important to us?
Workbook activities 1.2 and 1.3
Energy in food
02_(S)MPaH_Ene5&6 TB(Std)_01.indd 5
5
8/26/15 2:21 PM