Matter states and its changes
-There are three states of the matter:
1- Solid state: such as sugar, salt, Iron, Copper and wood.
2- Liquid state:such as water, oil, milk, benzene, Kerosene and Alcohol.
3- Gaseous state:such as oxygen, nitrogen, carbon dioxide and water vapour.
Notes:
Matter consists of small building units called molecules or particles.
1-Solid state:
Its properties:
1-Its molecules are packed very closely together.
2- It has a definite shape and volume.
Activity: To prove that Solid matter has a definite shape and volume.
Steps:
1. Put a piece of stone and marble in a test tube.
2. Compare between the shape and volume of each body in the test tube and its real shape and volume.
Observation: shape and volume of each body don't change.
Conclusion: Solid matter has a definite shape and volume.
2-Liquid state:
Its properties:
1-Its molecules are far from each other (the distance between molecules is larger than that of solids).
2- It has a definite volume and an indefinite shape.

Activity: To prove that liquid matter has a definite volume and an indefinite shape.
Steps:
1-Put 100 cm3 of water in a conical flask and pour them in cylindrical flask.
Observation: The volume of water doesn't change but its shape changes taking the shape of its container.
Conclusion: liquids have a definite volume and an indefinite shape (they take the shape of its container).
3-Gaseous state:
Its properties:
1-Its molecules are very far from each other (the distance between molecules is larger than that of liquids).
2-It hasn't a definite shape or volume.
Activity: To prove that gaseous matter hasn't a definite shape or volume.
Steps:
1- Blow air in a balloon and tie it with a thread.
2- Press on the balloon with your hand.
Observation: The shape and volume of air changes by pressing on the balloon.
Conclusion: Gases always take the shapes and volumes of their containers (they don't have a definite shape or volume).
Notes:
-In oxygen and butagas cylinders the gas is compressed inside them where its shape and volume is changed.
Comparison between the three states of matter