Physics – Measurements, Matter & Molecules, Forces (Brief Notes)
S.I. Units
Volume m3 Length m (metres)
Mass kg Time s (seconds)
When taking measurements:
Read the ruler at eye-level to avoid parallax error.
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Matter & Molecules
Matter is made up of tiny particles called atoms.
The 3 States of Matter are: Solids, Liquids, Gases
Describing the Movements of the Particles in States of
Matter:
Solids closely packed, fixed shape & volume,
vibrate
Liquids flow, take shape of the container, fixed
mass & volume, move more freely than solids and
slide past each other
Gases spread, move freely at high speeds, no
fixed volume
Water can be observed in its three states – ice (solid), water
(liquid), water vapour (gas)
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Density
Density is the mass per unit volume.
The density of a material tells us how much mass is present
in 1m3 of the material.
If a material floats over water, it means it has a lower
density than that of water.
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, If a material sinks over water, it is denser than water.
What is the difference between mass and volume?
Mass: amount of matter in an object, measured in kg
Volume: space occupied by an object, measured in m3
The Equation for Density
m
ρ=
v
Keep in mind the variations of this equation:
m
m= p × v v=
p
The S.I. Unit of Density is: kg /m3
To change from g/cm3 to kg/m3 – Multiply by 1000
To change from kg/m3 to g/cm3 – Divide by 1000
________________________________________________________________
Drawing a Graph
The below is an example of how it should be done:
A graph of mass/g against volume/cm3 for water
Volume (cm3)
________________________________________________________________
Questions
i) Define the movement of particles in:
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S.I. Units
Volume m3 Length m (metres)
Mass kg Time s (seconds)
When taking measurements:
Read the ruler at eye-level to avoid parallax error.
______________________________________________________________
Matter & Molecules
Matter is made up of tiny particles called atoms.
The 3 States of Matter are: Solids, Liquids, Gases
Describing the Movements of the Particles in States of
Matter:
Solids closely packed, fixed shape & volume,
vibrate
Liquids flow, take shape of the container, fixed
mass & volume, move more freely than solids and
slide past each other
Gases spread, move freely at high speeds, no
fixed volume
Water can be observed in its three states – ice (solid), water
(liquid), water vapour (gas)
______________________________________________________________
Density
Density is the mass per unit volume.
The density of a material tells us how much mass is present
in 1m3 of the material.
If a material floats over water, it means it has a lower
density than that of water.
1 | Page
, If a material sinks over water, it is denser than water.
What is the difference between mass and volume?
Mass: amount of matter in an object, measured in kg
Volume: space occupied by an object, measured in m3
The Equation for Density
m
ρ=
v
Keep in mind the variations of this equation:
m
m= p × v v=
p
The S.I. Unit of Density is: kg /m3
To change from g/cm3 to kg/m3 – Multiply by 1000
To change from kg/m3 to g/cm3 – Divide by 1000
________________________________________________________________
Drawing a Graph
The below is an example of how it should be done:
A graph of mass/g against volume/cm3 for water
Volume (cm3)
________________________________________________________________
Questions
i) Define the movement of particles in:
2 | Page
