<< Chapter < Page Chapter >> Page >

Natuurwetenskappe

Energie-oordrag en kragte

Opvoeders afdeling

Memorandum

Waarnemings:

(i) Die rook trek opwaarts.

(ii) Die rook trek opwaarts.

(iii) Die rook trek opwaarts.

Afleiding:

Warm lug styg op.

Gedurende die dag word die land vinniger warm as die see. Die warm lug bo die land styg op. Koeler lug bo die see vloei na die land om die plek van die warm lug in te neem. So ontstaan seewinde.

Snags koel die land vinniger as die see af. Die warm lug bo die see styg dus. Koeler lug bo die land vloei na die see om die plek van die warm lug in te neem. So ontstaan landwinde.

Leerder afdeling

Inhoud

Aktiwiteit: om stroming as natuurverskynsel te verklaar [lu 1.1, lu 1.2, lu 1.3]

(b) Stroming

Stroming is die belangrikste manier waarop warmte deur ‘n vloeistof beweeg. Water is ‘n swak geleier van warmte, maar tog kry ‘n ketel dit reg om water vinnig te laat kook. Dit is omdat vloeistowwe kan beweeg. Wanneer die water warm word, styg dit. Koue water daal dan af om die plek in te neem van die warmer vloeistof wat opgestyg het. In die meegaande skets sal jy sien dat hierdie sirkelbeweging, ‘n konveksiestroom, die warmte deur die vloeistof versprei totdat al die water later so warm is dat dit kook (100º C – kookpunt van water by seespieël).

Alhoewel lug ook ‘n swak geleier van warmte is, kry ons dit reg om ‘n vertrek met behulp van ‘n verwarmer te verhit. Neem ‘n brandende kers. Hou die rigting van die rook dop terwyl jy

(i) die kers regop hou __________________________________________________

(ii) die kers skuins hou _________________________________________________

(iii) die kers onderstebo hou _____________________________________________

Noteer jou waarnemings. Watter afleiding kan jy maak?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

Omdat warm lug styg, vind daar ook stroming in die natuur plaas. Het jy al gewonder waar wind vandaan kom? Warm lug styg en koue lug neem die plek daarvan in.

Gebruik die beginsel van konveksiestrome in lug om te onderskei tussen land- en seewind. Jy kan ook ‘n skets maak om jou gegewens te verduidelik.

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

(c) Straling

Om energie oor te dra deur geleiding of stroming is ‘n vaste stof, ‘n vloeistof of ‘n gas nodig. Daar moet een of ander stof wees om die warmte-energie oor te dra. Deur straling kan energie deur ‘n leë ruimte oorgedra word. Warmte-energie van die son beweeg deur die ruimte en deur die aarde se atmosfeer en wanneer dit ‘n voorwerp tref, word die voorwerp verhit.

As mens op ‘n baie warm dag op ‘n pad ry waar jy ver voor jou uit kan sien, lyk dit asof daar water op die teerpad lê. Die warm teerpad straal hitte uit. ‘n Voorbeeld van straling in die alledaagse lewe is wanneer ons in die winter ‘n elektriese verwarmer gebruik om ‘n vertrek te verwarm.

6. Omsetting van energie

Watter soort energie gebruik die seun om die tennisbal te slaan?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

______________________________________________________________

Watter soort energie het die bewegende tennisbal?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

______________________________________________________________

Jy het waarskynlik nou die idee gekry dat energie kan verander. Wanneer energie van een soort verander in ‘n ander soort, vind energie-omsetting plaas.

Assessering

Leeruitkomste 1: Die leerder is in staat om met selfvertroue op weetgierigheid oor natuurlike verskynsels te reageer, en om binne die konteks van wetenskap, tegnologie en die omgewing verbande te ondersoek en probleme op te los.

Assesseringstandaard 1.1: Dit is duidelik wanneer die leerder ondersoeke beplan: beplan eenvoudige toetse en vergelykings en dink na oor hoe om dit billik te maak;

Assesseringstandaard 1.2: Dit is duidelik wanneer die leerder ondersoeke uitvoer en data versamel: organiseer en gebruik toerusting of bronne om inligting in te versamel en aan te teken

Assesseringstandaard 1.3: Dit is duidelik wanneer die leerder data evalueer en bevindings kommunikeer: veralgemeen ten opsigte van ‘n relevante aspek en beskryf hoe die data die veralgemening steun

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
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Natuurwetenskappe graad 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11078/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natuurwetenskappe graad 7' conversation and receive update notifications?

Ask