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Natural sciences

Grade 8

Energy: electricity, heat and light

Module 10

Heat and temperature

Heat is a type of energy – the energy of the movement of particles. Temperature is the measure of how fast the molecules are moving

How do we measure temperature?

We use a thermometer that consists of a glass tube filled with a liquid such as mercury, which expands when it is warmed.

What is absolute zero ?

The lowest temperature possible, at which it becomes impossible for molecules or atoms to move. This occurs at –273,15 ºC or at 0 on the Kelvin scale. This low temperature was measured in a Finnish laboratory.

Find out what the Kelvin scale is.

You probably know that temperature can be measured on a Celsius scale or on a Fahrenheit scale. Temperatures used to be measured in Fahrenheit, so you may still find appliances that are marked in Fahrenheit, but most appliances nowadays use the Celsius scale.

How do you convert Fahrenheit to Celsius?

Subtract 32 and then divide by 9 and multiply by 5

F to C therefore is (-32 ÷ 9 x 5)

For Celsius to Fahrenheit it is:

÷ 5 x 9 + 32

Activity:

To understand temperature conversions [lo 2.4]

Assignment 1:

Do you know the following?

1. The highest temperature ever recorded on earth is 720 million ºF. It was recorded during nuclear fusion, in the USA.

What would this be in ºC?

2. The highest air temperature has been measured in Libya, at 58 ºC.

What is this in ºF?

3. The lowest air temperature was recorded in Antarctica when the thernometer registered –190 ºF.

What is this in ºC?

Try: www.convert-me.com

Assessment of Temperature Conversions

Were you able to do the conversions?

[LO 2.4]

Heat Transfer

Activity:

To determine terms and concepts involved with the transfer of heat [lo 2.1, lo 2.3, lo 2.4]

Assignment 1:

Complete:

There are different terms for describing the transfer of heat:

  • CONVECTION
  • CONDUCTION
  • RADIATION

Assessment of Terms

Were you able to identify the terms?

[LO 2.4]

Heat and Water

Water has a remarkable capacity for retaining heat.

Much energy is needed for the temperature of water to increase or decrease by 1 ºC.

Various factors influence heat retention by water:

  • Water is a liquid.
  • Water is transparent and light beams can penetrate to a depth of 20 m.
  • A mass of water has waves and currents and vertical movement that can distribute heat.

If you compare the heat retention capacity of the land and the oceans, you will realise that there is a considerable difference.

Capacity for heat

We know that heat causes changes in temperature and that a unit of heat is measured in Joule as it is a type of energy.

Specific heat capacity is the amount of heat that is transferred (required or released) when the temperature of a substance changes by 1 ºC or 1 K.

Water is the most expensive substance to heat because great amounts of heat are required to raise the temperature of water by a few degrees. Water, on the other hand, also provides large amounts of heat when it cools down.

The effect of this is most marked in the oceans, as they are large masses of water. They are warmed very slowly, but also retain the heat for a long time.

Questions & Answers

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
salma
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
Abhi
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
hmm
Abhi
is it a question of log
Abhi
🤔.
Abhi
I rally confuse this number And equations too I need exactly help
salma
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
salma
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
hii
Uday
hi
salma
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
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
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Source:  OpenStax, Natural sciences grade 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11050/1.1
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