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1. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
Matter and Density
Learning Objectives
• What are the three states of matter
• How do particles behave in the three states of matter
• Name and describe the processes of changing state.
• Recall and use the formula for density
• Describe how to determine the density of regular solids, irregular solids,
liquids and gases.
The 3 states of matter
The 3 states of matter are …solid…….. , …liquid…….. and …gas…….
Solid Liquid Gas
Particle
arrangement
Closely …
packed…….
…Regular..
arrangement (lattice)
Closely …packet….
No fixed/no regular
arrangement. …
Randomly….
arranged.
…Spread…. out
Large ..Spaces.
between particles. …
randomly.. arranged.
Particle
movement
…vibration…. only Move randomly but
with limited …… .
Slide past each other
Particles are free to
move. Particles move
……… at high speed.
Particles ………. off
each other and the
walls, which exerts a
force.
Forces
between
particles
Strong, spring-like
forces.
Fixed in place
Strong forces of
attractions
Zero (Ideal gas)
Particles in all states of matter are constantly ……in motion……...
This is called the …kinetic…. THEORY of matter.
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2. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
Changing State
……sublimation……..
…melting.... …evaporation..….
Solid Liquid Gas
…freezing../…solidification… …condensation…..
… deposition……
We need to describe:
Melting
Melting is the change of state where a …solid.… becomes a …liquid… at the …
melting.. point. The …melting. Point is the temperature at which the solid melts.
Boiling
Boiling is the change of state where a …liquid…… becomes a …gas… at the …
boiling….. point. The …boiling…. Point is the temperature at which the liquid
boils.
Evaporation
Evaporation is the change of state where a …liquid… becomes a …gas… at a
temperature …hotter….. than the boiling point.
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3. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
Density
Density is a measure of how much ………… is present in each unit …………… .
Density = mass / volume
(kg/m3
) (Kg) (m3
)
Or (g/cm3
) (g) (cm3
)
The symbol for density is the Greek letter ρ ‘Roe’
So ρ = mass / volume
We will conduct experiments to determine the density of:
a. Regular solids
b. Irregular solids
c. Liquids
d. Gases
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4. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
A. How to determine the Density of a regular object.
Method
1. Measure mass on a balance
2. Measure dimensions using Vernier callipers.
3. Repeat measurements and calculate
average dimensions
4. Calculate volume
5. Calculate density
Eg 1. Density of a …aluminum…. cuboid:
1. Mass measure by a balance = ...22.44… g
2. Dimensions; length = …1.82... cm, width = ….1.82… cm, height = …1.82...
cm
3. Volume = l x w x h = …1.82….. x …1.82… x ……1.82…. = …6.03… cm3 (3.s.f)
4. Density = mass / volume = …22.4…. / …6.03…. = …3.71…. g/cm3 (3.s.f)
Eg 2. Density of a brass sphere:
1. Measure mass by a balance = …26.10….. g
2. Dimensions; diameter = …1.62… cm, radius = … 0.81 .. cm
3. Volume = 4/3 x π x r3
= 4/3 x π x ……….3
= ……………. cm3
4. Density = mass / volume = ………. / …………. = ………. g/cm3
Homework: P 17 Q 1- 9
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Safety.
Careful with sharp
points on Vernier
callipers.

5. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
B – Determine Density of an Irregular Solid
Method
1. Measure mass using top-pan balance
2. Measure Volume by displacement of
water. (the Ureka moment), using one of
these techniques:
2a. For small objects measure
displaced volume using a
measuring Cylinder.
 Measure accurately
approximately 50cm3
of water in
a measuring cylinder.
 Submerge object
 Measure new volume
 Displaced Vol = new vol –
original vol
2b. For larger objects measure displaced
volume using a displacement can.
• Fill a displacement can to
overflowing.
• Submerge object
• Measure displaced volume using a
measuring cylinder
Note - if the object floats, press it down with a tiny stick to fully submerge it.
3. Repeat displaced volume measurement to get an average.
4. Calculate Density using
Density = Mass / volume
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New
Vol
Orig.
Vol
Safety.
Beware of spills
which are a slip
hazard.

6. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
C. Determine Density of a Liquid.
Method
1. Place an empty measuring cylinder on a top pan balance
2. Hit TARE to zero reading.
3. Add approx 50cm3
of the liquid.
4. Record the mass.
5. Accurately measure the volume.
6. Calculate the density using:
Density = mass / volume
7. Repeat and calculate an average.
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Safety.
• Beware spills
which are a slip
hazard.
• In particular, oil
spills must be
wiped up
immediately.
50.00g00.00g
Read to the ……….……..
of the meniscus.

7. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
D. Determine Density of a Gas, eg Carbon Dioxide
Method
1. Place conical flask with limestone chips and beaker of 0.2M
HCl on a top pan balance
2. Hit TARE to zero reading.
3. Add approx 10ml of acid to excess of limestone chips.
4. Accurately measure volume of gas by downward displacement of water,
once bubbles have stopped being released.
5. Remove the delivery tube and record the mass loss from reactants.
6. Calculate the density using:
Density of gas = mass lost / volume collected
7. Repeat and calculate an average.
Homework P19, Q1-2 and P20, Q 1 - 2
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Safety.
• Acids are
corrosive
• Use safety
goggles
00.00g
0.2M
HCl
Limestone
Chips

8. FUNDAMENTAL Physics – Matters : 2.1 Matter and Density
Extension:
Does an egg float:
http://www.youtube.com/watch?v=fqLCwuKMBMA
It depends ……
1. On the liquid…..
2. On the egg …..
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