<< 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

how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
hii
Uday
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele 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!
QuizOver.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