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Natural sciences

Grade 4

Energy and change

Module 31

Food as a source of energy


To discuss and describe food as a source of energy

[lo 1.1, 1.2, 1.3]

We have to take in food to obtain energy, and eat enough to keep going for long enough. If we do not eat enough, our bodies will not remain warm and we will not have enough energy to do our daily work. To remain healthy, we have to follow a balanced diet. It is possible to know whether you eat correctly and get enough to eat by studying the information on the boxes, packets, bags and tins in which food is bought to find out how much energy per volume is contained in the foodstuff. The quantity that is eaten is measured in kilojoules.

Some of the energy that animals obtain from the food that they eat is stored in their muscles. Those muscles are able to use the energy to do work.

In early times, people used the energy of their own muscles to do work, like gathering food, tilling their fields and building shelters. They made simple implements to help them use this energy more efficiently and to work better. The first tools were made of wood and stone, but when people discovered how to melt down metals, they used metal to make better and stronger tools.

They also discovered that they could use animals to work faster and better and get more work done, as one ox is able to do the work of eight grown men.

Animals were used to transport people and goods, to pull the ploughs in the fields and to pump water from below the ground to irrigate the fields.

Work out a balanced diet by examining the labels on different containers in which food is packed.

  • Learners must be divided into three groups: Group 1 must determine the kilojoules value of breakfast; Group 2 the kilojoules value of lunch; and Group 3 the kilojoules value of supper.
  • Each group must then report their findings concerning the value of the specific meal with regard to the energy requirement for the day.



The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

Assessment Standard

We know this when the learner

  • plans investigations;
  • leads investigations and collects data;
  • evaluates data and provides feedback on observations.



This assignment involves research. Help the learners to plan their research, to collect information, to draw conclusions and to communicate their findings.

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Natural sciences grade 4. OpenStax CNX. Sep 18, 2009 Download for free at http://cnx.org/content/col11096/1.1
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