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Natural sciences

Grade 8

Matter: classification

Module 15

Phase changes of matter

Prior Knowledge:

  • Matter has three phases: solid substances, liquid substances and gases

Class activity: reading skill

In the heart of a Cape winter

Adventurers went camping in the Cedar Mountains.

The night brought a fall of snow that

Glistened in the early morning light.

Slowly, surely, the ice was melted by the wintry sun

And water ran in rivulets to the riverbed.

A camper scooped up a billycan of the stream’s water

He struck a match to light his fire

And soon steam billowed from his billycan!

1. Name all the phases of water mentioned in the text – list all the descriptive words.

2. Name the source of energy that causes:

a. the ice to melt

b. the water to steam

3. a. In which phase do particles of water have the greatest freedom of movement?

b. Which phase presents the strongest attraction between particles of water?

4. The phases of water are also an important part of nature, as the WATER CYCLE becomes possible because of it. Fill in the following:

The Water Cycle

6. The following illustrations represent phase changes. Explain what happens to the water in each instance:

Assessment of reading skills

Were you able to make the correct deductions from the text?

[LO 2.3]


Find out the following:

(You could use the given web addresses or any other source for research.)

Why ice floats on water.– www.geocities.com (iceberg+ float)

How snowflakes are formed.– google.com (snowflakes)– www.edu.pe.ca/rural/chemist

Why alcohol (as in Schnapps or Witblits) does not freeze in the freezer.

What the boiling point of fluids like cooking oil and alcohol is.– www.ucc.ie – (boiling points)

Paste or write the information on the facing page.

Assessment for assignment

Has the information been collected and recorded?

[LO 1.3]

7. Each substance has its own boiling and freezing point.

Water freezes at

Water boils at

 Do you know the following? 

A fourth phase of matter has been discovered – it is known as PLASMA.

It only occurs at excessively high temperatures and in stars.

Read more about PLASMA!



Learning outcomes 1: Scientific investigations

The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

We know this when the learner

1.3 is able to evaluate data and communicate findings.

Learning outcomes 2: Constructing science knowledge

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

We know this when the learner

2.3 is able to interpret information.


1. snow; ice (solid substance) – water; river water (liquid) – steam (gas)

2. a) sun b) fire

3. a) steam (gas) b) snow/ice

4. spaces smaller in solid substances

5. 1 – evaporation; 2 – transpiration; 3 – cloud formation / condensation

4 – precipitation (rain, snow, etc.)

6. condenses; melts; freezes (crystallises); evaporates

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
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Devang Reply
are you nano engineer ?
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
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.
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for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
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abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
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I'm interested in nanotube
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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
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what is the application of nanotechnology?
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
anybody can imagine what will be happen after 100 years from now in nano tech world
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
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
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I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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.
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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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