Transcript Matter Chapter Eleven: Temperature, Heat and the Phases of Matter • 11.1 Temperature and the Phases of Matter • 11.2 Heat.

Matter
Chapter Eleven: Temperature,
Heat and the Phases of Matter
• 11.1 Temperature and the
Phases of Matter
• 11.2 Heat
Investigation 11B
The Phases of Matter
• How do the mass,
volume, and
densities of solid,
liquid, and gas
compare?
11.2 What is heat?
• Heat is thermal energy that
is moving.
• Heat flows any time there is
a difference in temperature.
• Because your hand has
more thermal energy than
the chocolate, thermal
energy flows from your hand
to the chocolate and the
chocolate begins to melt.
11.2 What is heat?
• Heat and temperature
are related, but are not
the same thing.
• The amount of thermal
energy depends on the
temperature but it also
depends on the amount
of matter you have.
11.2 Units of heat and
thermal energy
• The metric unit for
measuring heat is
the joule.
• This is the same
joule used to
measure all forms
of energy, not just
heat.
11.2 Heat and thermal energy
• Thermal energy is often measured in
calories.
• One calorie is the amount of energy it takes
to raise the temperature of one milliliter of
water by one degree Celsius.
11.2 Specific heat
• The specific heat is a
property of a substance
that tells us how much
heat is needed to raise
the temperature of one
kilogram of a material
by one degree Celsius.
Knowing the specific heat of a material tells you how
quickly the temperature will change as it gains or loses
energy.
11.2 Why is specific heat
different for different materials?
• Temperature measures the average kinetic energy
per particle.
• Energy that is divided between fewer particles
means more energy per particle, and therefore
more temperature change.
• In general, materials made up of heavy atoms or
molecules have low specific heat compared with
materials made up of lighter ones.
11.2 Heat transfer
• Heat conduction is the
transfer of heat by the
direct contact of particles
of matter.
• Conduction occurs
between two materials at
different temperatures
when they are touching
each other.
Where is the heat energy
conducted to and from in
this system?
11.2 Heat transfer
• Thermal equilibrium occurs when two
bodies have the same temperature.
• No heat flows in thermal equilibrium
because the temperature is the same in the
two materials.
11.2 Thermal conductors and
insulators
• Materials that conduct
heat easily are called
thermal conductors
and those that conduct
heat poorly are called
thermal insulators.
Is a down coat a
conductor or an
insulator?
11.2 Convection
• Convection is the transfer
of heat through the motion
of matter such as air and
water.
• In a container, warmer
fluid rises to the top and
cooler fluid sinks to the
bottom.
• This is called natural
convection.
11.2 Convection
• Convection is mainly what distributes heat
throughout a room.
11.2 Thermal radiation
• Heat from the Sun is
transferred to Earth by
thermal radiation.
• The higher the
temperature of an object,
the more thermal
radiation it emits.
• All the energy the Earth
receives from the Sun
comes from thermal
radiation.
11.2 Thermal radiation
• Thermal radiation is also
absorbed by objects.
• The amount of thermal
radiation absorbed
depends on the surface of
a material.
• Dark surfaces absorb
most of the thermal
radiation they receive.
• Silver or mirrored surfaces
reflect thermal radiation.
Technology Connection
Extraordinary Materials
• Many materials you are
familiar with were
discovered accidentally.
• Other materials were
created in a laboratory
with a particular use in
mind.
Activity
Magical Ice Cream Topping
• Have you ever put a
“shell” topping on a
frozen dessert like ice
cream?
• It is a liquid in the plastic
bottle, but when you put
it on ice cream, it
hardens very quickly.