science primary 4 Egyptian curriculum

1. Physical and chemical
changes of matter
Unit 1:lesson 4

2. Revision
• Matter is every thing around us .
• Matter is anything that has mass and takes up space.
• Matter is composed of molecules .
• States of matter :
• Each matter has different properties.
Solid
liquid
Gas

3. Physical properties
• look at a coin in your pocket. It is made from a metal. You can tell
it is made from a metal because it is shiny and maybe has a silvery
color. Those two descriptions I gave it are called physical
properties.
• A physical property is a characteristic that can be observed or
measured without changing the composition.

4. Chemical properties
• A new iron nail is made of iron metal, iron that was used to make iron nail is not
the most stable of the metals. When it is exposed to oxygen it transforms into
rust. This ability to react to oxygen to form rust is called a chemical property
• Rust has its own properties. First, unlike iron , it is brittle. It's also a dull
reddish-brown color.
• A chemical property is a characteristic that can only be determined by changing
the chemical identity of a substance.

5. Changes of
matter

6. • In our daily life we observe that matter can change it’s not on the
same physical and chemical state all the time ,
• Chocolate and ice cream melt down in hot weather.
• Iron rusts.
• Milk go sour .
• How can we classify these changes ?

7. • When we cut a paper into pieces only it’s shape changes .
• We can say that this change is physical change .
• As the appearance of matter only changed without any change in it’s
structure .
• (it's still paper)
• This is called :

8. • If you burn a paper it turns into ash .
• It’s not paper anymore .
• It’s shape and structure changes .
• You can see that ashes is different than paper in shape and
structure
• It’s called :

9. Physical changes
of matter

10. Ice cycle

11. Ice cycle
Materials Glass beaker-glass surface –a flame
A stand- container – ice
Procedure • Put the ice in the beaker .
• Heat until ice melts .
• Continue heating the formed water.
• Put the glass surface facing the produced water vapor.
• Put the assembled water in the freezer
Observation • Ice melts into water.
• Water boils producing water vapor.
• Water vapor condensate into water drops.
• Water changes into ice again in the freezer ,
Conclusion The change from one state to another (melting-evaporation-
condensation-freezing )
Is a physical change as the shape of water changes but it’s
structure doesn’t

12. Melting of wax
Materials Glass watch –match stick
A candle
Procedures • Fix candle on the glass.
• Light the candle .
Observation • The wax melts and changes into liquid drops.
• The liquid wax solidifies again
Conclusion Melting wax changes it’s shape but it’s structure doesn't
change
It’s physical change

13. Grinding of sugar
Materials Mortar
Cube of sugar
Procedure • Taste the sugar
• Put the cube in the clean mortar
• Grind the cube
• Taste again
Observatio
n
• The sweet taste of sugar doesn't change by grinding but its
shape changes into fine powder
Conclusion Grinding sugar is a physical change as the shape of sugar
changes but it’s structure and properties doesn’t change.

14. Dissolving of table salt in water
Steps Observation
Taste the salt . Salt taste is salty.
• Add a spoon of table salt
to the water in the
beaker
• Stir to dissolve
completely .
• The salt disappears .
• It’s shape has changed.
Pour the content into a
crucible .
Put the crucible on the
flame until the water
evaporates .
Remove from heat wait to
cool taste the residue.
The remaining residue is
table salt
Dissolving of table salt or sugar in water is a physical change as the shape of table salt or
sugar changes but it’s structure doesn't change

15. Physical change of matter
•The change in the appearance of
matter without change in it’s
structure

16. Examples of physical changes
• Changing of matter from one state to another :melting evaporation &
condensation .
• Grinding sugar or chalk into powder.
• Dissolving or salt or sugar in water.
• Malleability of metallic elements to form sheets or wires.
• Cutting paper or wood into smaller pieces.

17. Chemical changes
of matter

18. Burning of paper
Materials White paper
Flame
Glass watch
procedures • Bend the paper.
• Burn the paper.
• Put the product of
burning in the watch glass.
• Compare the
characteristics of the paper
before and after burning
observation • The white paper
changes into black ash.
• The shape and structure
of the white paper is
different from the black
ash .Conclusion:
The paper burns and changes into black ash and can’t be returned back to its first form again

19. Burning paper is a chemical change as the shape and
structure of the white paper change by burning .

20. Burning of sugar
Materials Crucible-flame – spoon of
sugar
Procedure • Put the sugar in the
crucible .
• Put the crucible on the
flame .
• Taste the residue after
cooling.
Observation • Sugar changes into
brown substance.
• Sugar looses it’s sweet
taste.
Conclusion Sugar changes into brown
color and loses it’s sweet
taste and can’t be returned
back to it’s sweet form
Burning sugar is a
chemical change as the
shape and structure of
sugar changed by heating

21. Iron rust
Materials Iron wire which is used
in cleaning dishes
Scissors-crucible-
magnifying lens
Procedure • Cut a piece of wire put it
in the crucible .
• Expose the piece of the
wire to wet air for a
certain period .
• Examine by the lens
Observation Formation of a brittle
brown rust layer
Conclusion Rusting is a chemical
change as the shape and
structure of the cleaning
wire changed when
exposed to air .

22. Examples of chemical change
• Iron rust
• Burning of substances (paper-wood-fuel-sugar)
• Production of yogurt from milk .
• Adding sodium bicarbonate to vinegar

23. Chemical change of matter
•the change in the structure of a
substance producing a new
substance with different properties

24. Physical vs chemical

26. Physical or chemical ?

28. Comparison between physical and chemical
changes
• Chemical changePhysical change Chemical change
Change in appearance of a
substance
Change in the structure of
substance
Examples Melting of substances
Dissolving of salt and sugar
Cutting and grinding things
Burning of substances
Iron rust

30. Good bye
Marwa salah