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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

explain and give four Example hyperbolic function
Lukman Reply
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
ok
Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
how do I set up the problem?
Harshika Reply
what is a solution set?
Harshika
find the subring of gaussian integers?
Rofiqul
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Shirley Reply
please can go further on polynomials quadratic
Abdullahi
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Mark
I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
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Mark
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
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Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
Shirley Reply
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Seidu
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Opoku
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Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
Shedrak
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
Alfred Reply
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
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?
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Source:  OpenStax, Natuurwetenskappe graad 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11049/1.1
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