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Natural sciences

Energy transfers and forces

Educator section

Memorandum

a)

  • Iron
  • Copper
  • Aluminium
  • Lead

All four are good conductors, but copper, for example, is a better conductor than iron. Determine positions by doing an experiment. Try to use laboratory rods that are of the same size.

(b) An eiderdown (or down duvet) keeps one warm because body heat is poorly conducted by it. The air between the down is also a poor heat conductor. Bricks also have tiny holes that are filled with air. That makes a brick a poorer conductor of heat than for example copper, which is more solid/compact.

(c)

(i) Clay.

(ii) It conducts heat poorly from outside; therefore it will remain cooler inside than outside.

(iii) Wool is a poor conductor and therefore it keeps the body heat inside.

(iv) The learner should choose a good conductor for the bottom of the pot especially, in order to get the heat to the contents of the pot rapidly to speed up the preparation time of the contents. He/she should choose a poor conductor for the handles of the pot, so that one can handle the pot without having to use potholders or a cloth.

(v) Water is a poor conductor.

(vi) Tins are made of aluminium, which is a better conductor than glass.

Leaner section

Content

Activity 6: to compare the conductivity of various substances [lo 2.2]

(a) Test the following metals by warming them in a flame or in boiling water. Let each member of the group hold a different metal rod. Report it as soon as the heat reaches your hand. Arrange the metals in such a manner that the metal that is the fastest conductor – the one that gets hot first – is placed in the first position.

Metal Position
Iron _______________________
Copper _______________________
Aluminium _______________________
Lead _______________________

(b) Why is it that some substances are better conductors than other substances?

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(c) Use your knowledge of conduction to answer the following questions.

(i) Which metal would you use to build a hut that needs to be cool in summer – clay or corrugated iron?

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(ii) Why have you chosen this as the building material?

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(iii) Have you ever thought about the reason for wearing woollen clothing in winter? Try to explain why winter garments contain wool.

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(iv)You have an opportunity to design a pot for cooking food. Which materials would you use, and why? (Remember that a pot also needs handles!)

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(v) Why do we put a bottle of cool drink in cold water when we want to keep it cool?

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(vi) Try to explain why cool drink in a bottle would remain cold longer than cool drink in a tin.

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Assessment

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.2: We know this when the learner categorises information: compares features of different categories of objects, organisms and events.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
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
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
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.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
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 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11077/1.1
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