<< Chapter < Page Chapter >> Page >

Natuurwetenskappe

Graad 8

Energie: elektrisiteit, energie, warmte en lig

Module 10

Hitte en temperatuur

Hitte is ‘n soort energie – alle atome / molekules vibreer. Ons ervaar dit as hitte.

Temperatuur is die meting van hoe vinnig die molekules beweeg.

Hoe meet jy temperatuur?

‘n Termometer word gebruik. Dit bestaan uit ‘n glasbuis met ‘n vloeistof, bv. kwik, daarin wat uitsit tydens verhitting.

Wat is absolute zero ?

Dit is die koudste moontlike temperatuur waarby molekules of atome glad nie meer kan beweeg nie. Dit gebeur by –273,15 ºC of by 0 op die Kelvin-skaal. Dit is in ‘n Finse laboratorium gemeet.

Vind uit: Wat is die Kelvin-skaal ?

Jy weet seker dat ‘n mens temperatuur op ‘n Celsius-skaal of Fahrenheit-skaal kan meet. Sommige toestelle meet in Fahrenheit, bv. oonde, terwyl ander weer Celsius gebruik.

Hoe skakel jy Fahrenheit om na Celsius?

(Grade F – 32) ÷ 9 x 5 = C

Om Celsius na Fahrenheit om te skakel:

F = C ÷ 5 x 9 + 32

Aktiwiteit 1:

Om temperatuuromskakeling te verstaan

[lu 2.4]

Opdrag 1:

Het jy geweet?

1. Die hoogste temperatuur wat ooit op aarde gemeet is, was 720 miljoen°F, tydens ‘n kernfusie-eksperiment in Amerika.

Hoeveel is dit in ºC?

2. Die hoogste lugtemperatuur gemeet, was 58ºC in Libië.

Hoeveel ºF is dit?

3. Die laagste lugtemperatuur gemeet was in Antarktika en dit was –190 ºF.

Hoeveel ºC is dit?

Probeer gerus: www. convert-me.com

Hitteoordrag

Aktiwiteit 2:

Om hitte-oordragterme en -begrippe vas te stel

[lu 2.1, 2.3, 2.4]

Opdrag 1:

Voltooi:

Daar is verskillende terme wat hitte-oordrag beskryf:

KONVEKSIE:

GELEIDING:

STRALING

Hitte en Water

Water het ‘n uitsonderlike hittehouvermoë.

Dit neem baie energie voordat ‘n massa water met 1 ºC styg of daal.

Daar is verskeie faktore betrokke:

  • Water is ‘n vloeistof.
  • Water is deurskynend en ligstrale kan tot 20 m diep penetreer.
  • Watermassa het golwe en strome en vertikale beweging wat hitte kan versprei.

As jy die hittehouvermoë van die land en die oseane vergelyk, sal jy besef dat dit baie verskil.

Warmtekapasiteit

Ons weet reeds dat warmte ‘n verandering in temperatuur veroorsaak en dat die eenheid van hierdie warmte in Joule gemeet word, aangesien dit ‘n soort energie is.

Spesifieke warmtekapasiteit is die hoeveelheid warmte wat oorgedra (benodig/vrygestel) word as die temperatuur van ‘n stof met 1 ºC of 1 K verander.

Water is die duurste om te verhit, omdat groot hoeveelhede warmte vereis word om die temperatuur slegs ‘n paar grade te laat styg. Water sal egter ook groot hoeveelhede warmte lewer, indien dit afkoel.

Die uitwerking hiervan is die duidelikste op oseane, wat groot watermassas is. Dit verhit baie stadig, maar hou dan lank die warmte.

Opdrag 2:

  1. Verduidelik hoekom kusdorpe so ‘n gematigde temperatuur het as jy dit vergelyk met binnelandse dorpe.

2. Koel tee die vinnigste af wanneer jy eers koue melk byvoeg en dit dan laat staan of wanneer jy dit eers laat staan en dan koue melk byvoeg? Verduidelik.

3. Hoekom is die water by die strand lekker warm op ‘n koue dag as dit op ‘n paar warm dae volg?

4. Watter faktore dra by tot water se besondere warmtekapasiteit?

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 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11049/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natuurwetenskappe graad 8' conversation and receive update notifications?

Ask