This document discusses the properties of matter and the different states of matter. It explains that scientific models must address real-world questions, include hypothetical entities and interaction rules, be consistent with evidence, and be revisable. It then focuses on the states of matter, describing liquids and gases as fluids that flow, and solids as fixed molecular structures. Key concepts covered include pressure, intermolecular forces, melting and boiling points, evaporation, condensation, and the composition and properties of Earth's atmosphere.

2. Properties of Matter
• Chapter Four: Density and Buoyancy
• Chapter Five: States of Matter

3. Scientific Models Must:
• 1. Address a question about something from the
real world
• 2. Include entities (sometimes invisible and/or
hypothetical) and rules for how they interact.
• 3. Be consistent with the evidence that we have,
and make predictions about future observations
• 4. Be revisable
• 5. Be public

4. Tanker Video

5. Chapter Five: States of Matter
• 5.1 Liquids and Gases
• 5.2 Solid Matter

6. Investigation 5A
The Phases of Matter
• How do the mass,
volume, and
densities of solid,
liquid, and gas
compare?

7. 5.1 Liquids and Gases
• A fluid is a form of matter that flows
when any force is applied.
• Gases and liquids are both called fluids.

8. 5.1 Liquids and Gases
• In a liquid, molecules can slide over and
around each other.
• This is why liquids flow and can change
shape.

9. 5.1 Liquids and Gases
• A gas is a phase of matter with high energy
molecules that can expand to fill a container.
• Molecules in a gas are free to move around and
so gases flow just like liquids.
Molecules in a gas have
much more energy than
molecules in a liquid.

10. 5.1 Liquids and Gases
• Gases flow like
liquids, but they also
can expand or
contract to
completely fill any
container.

11. 5.1 Pressure
• Forces in fluids are more complicated than
forces in solids because fluids can change
shape.

12. 5.1 Pressure
• A force applied to a fluid creates
pressure.
• Pressure acts in all directions, not just
the direction of the applied force.

13. 5.1 Pressure
• On the microscopic
level, pressure comes
from collisions between
atoms.
• Every surface can
experience a force from
the constant impact of
trillions of atoms.
• This force is what we
measure as pressure.

14. 5.1 Pressure
• The pressure inside
your tire is what
holds your car up.

15. 5.1 Pressure
• There are two types of forces that act
between atoms.
– The strongest forces are between atoms that
are bonded together into molecules and
compounds.
– A weaker type of force acts between
molecules, or between atoms that are not
bound together.
• We call these weak forces intermolecular
forces.

17. 5.1 Intermolecular Forces
• The phases of matter (solid, liquid, gas) exist
because of competition between thermal energy
and intermolecular forces.
– When molecules have a large amount of thermal
energy (high temperatures), intermolecular forces are
overcome and the molecules spread apart, as in a
gas.

18. 5.1 Intermolecular Forces
– When molecules have a medium amount of
thermal energy, they come together to form a
liquid because the intermolecular forces are
partially overcome.

19. 5.1 Intermolecular Forces
– When molecules have a small amount of
thermal energy, the intermolecular forces are
stronger and molecules become fixed in
place as a solid.

20. 5.1 Melting and boiling
• The melting point is the temperature at
which a substance changes from a solid
to a liquid.

21. 5.1 Melting and boiling
• The temperature at which a liquid
becomes a gas is called the boiling
point.

23. 5.1 Melting and boiling points of
common substances
• Materials have a
wide range of
melting and
boiling points.

24. 5.1 Melting and boiling points of
common substances
• Most materials have a
higher density as a solid
than as a liquid.
• Water is an exception.
• Ice wouldn’t float if ice
were more dense than
water!
• Ice helps fish and other
aquatic organisms to
survive over long, cold
winters because the
protective layer keeps
the water below it
warmer.

25. 5.1 Evaporation and Condensation
• Evaporation occurs
when molecules go from
liquid to gas at
temperatures below the
boiling point.
• Evaporation takes
energy away from a
liquid because the
molecules that escape
are the ones with the
most energy.
Sweat evaporating from
skin removes energy and
cools the body.

26. 5.1 Evaporation and Condensation
• Condensation
occurs when
molecules go from
gas to liquid at
temperatures below
the boiling point.
Dew forms when water
vapor in air condenses into
droplets.

27. 5.1 Convection
• Convection is the transfer of
heat through the motion of
fluids such as air and water.
• Convection occurs because
fluids expand when they heat
up.
– Convection currents occur while
heating water.
– The hot water at the bottom of
the pot rises to the top and
replaces the cold water.

28. 5.1 The atmosphere of Earth
• Air is the most important mixture of gases to
living things on the Earth.
• Air may seem like “nothing” but all the oxygen our
bodies need and all the carbon needed by plants
comes from air.
• Molecular nitrogen (N2) and oxygen (O2) together
account for 97.2 percent of the mass of air.
• Argon and water vapor make up most of the rest.

30. 5.1 The atmosphere of Earth
• As a tree grows, you will
not see soil disappear to
provide mass for the tree.
• The oxygen and hydrogen
atoms in the tree come
from water.
• The carbon atoms come
from the carbon dioxide
(CO2) in the air.

31. 5.1 The atmosphere of Earth
• Earth’s weather is created by gigantic
convection currents in the atmosphere.

32. 5.1 The atmosphere of Earth
• Gravity creates
pressure because fluids
have mass and weight.
• The Earth’s atmosphere
has a pressure due to
the weight of air.
How does pressure change with
altitude in the atmosphere?