The document discusses various topics relating to heat. It defines heat as the total kinetic energy of molecules and explains how heat flows from hot to cold objects until equilibrium is reached. Heat is measured in calories, joules, or BTUs and depends on the mass and energy of particles. While heat is the total kinetic energy, temperature is a relative measure of particle speed. When substances are heated, their particles move faster and volume increases, making the substance less dense. The three main states of matter are solid, liquid, and gas. Heat of fusion and heat of vaporization refer to the energy required for phase changes. Heat transfer occurs through conduction, convection, and radiation.

1. HEAT

2. HEAT
 Heat
is the total kinetic
(moving) energy of all
molecules.
 Depends
on the mass and
energy of the particles!

3. If you have a cup of water the
same temperature as the
ocean, which has more heat
energy?

4. How does heat flow?
 Heat flows from hot to
cold until the heat is
balanced which we call
equilibrium.

5. A metal cup containing water
at 100F is placed in an
aquarium containing water at
80F:
 A) Which way will heat flow? Why?
 B) When will the flow of heat stop?
 C) What is it called when heat no
longer flows?

6. How is heat measured?




It is measured in calories, joules, or BTUs
A calorie is the amount of heat used to raise the
temperature of one gram of water one degree
Celsius.
One calorie = 4 joules
One Calorie (food)=1000 calories (4,000 J)

7. What is the difference between
heat and temperature?
 Heat
is the total amount of kinetic energy
available.
 Temperature is a relative measure of the
speed of the particles.
 Temperature is measured in degrees.
 Temperature and heat are not the
same!!!!

8. What happens when a
substance is heated?
 The speed of the
particles increases
which causes the space
between the particles to
increase

9. How does heat affect volume?
 Volume
increases with more
heat. More heat means that
the molecules are moving
faster (more kinetic energy),
therefore they bump into one
another and spread out.
 Less heat means less volume!

10. What effect does heat have on
density?

When a substance is
heated, it expands,
volume increases
therefore it becomes
less dense.

11. Temperature Scales
 The
2 main temperature
scales are Celsius and
Fahrenheit.
 Boiling
point is 100 C & 212 F
 Freezing is 0 C & 32 F

12. Kelvin Scale
A third temperature scale used
mainly for scientific purposes,
where absolute 0 is the coldest
possible temperature.
It starts at 0 (which is absolute 0)
Boiling 373
Freezing 273

13. Absolute Zero
 Absolute zero is the
temperature where there is an
absence of heat. There is no
motion of molecules. It has
not been reached in real life
or in a lab, but scientists have
gotten very close.

14. ABSOLUTE ZERO
 Absolute Zero = -460 F
 Absolute Zero = -273 C
 Dry Ice = -110 F
 Coldest Place on Earth = -70 F

15. What is specific heat?
 The
amount of energy needed to raise
the temperature of 1 kg of a substance
by 1 degree Celsius.
 The ability of a substance to absorb
heat.
 This property can help identify
substances.

16. Example of Specific Heat
 How
much energy does it take to raise
the temperature of 2 kilograms of
water by 3°C (specific heat of water is
4,184 J/kg°C)
 Solution: 2 kilograms x 3°C = 6 kg°C
 4,184 J/ kg°C x 6 kg°C = 25,104 J

17. What are the 3 states of matter?
Solid-has a defined volume and
shape.
Liquid-defined volume, takes the
shape of its container.
Gas-no defined shape or volume.

18. Sketch these pictures

19. What is heat of fusion?
The amount of energy
used to melt one gram
of a substance without
changing its
temperature.

20. What is heat of vaporization?
 The phase change when a liquid becomes a
gas.
 The energy needed for one gram of a
liquid to become a gas without changing
the temperature.
 The particles gain enough energy to permit
them to escape the surface of the liquid and
become a gas.

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22. CONDUCTION
 Conduction is the direct transfer of heat.
 Does conduction happen better in solids,
liquids, or gases?
Conduction
works best
through solids!

23. CONVECTION
 Convection is when
warmer less dense
material rises and is
replaced by cooler,
more dense material.
It then becomes
heated and rises
creating a current
(or repeating cycle!).

24. RADIATION
 Radiation involves
the transfer of heat
through the air
or a vacuum!
ALL objects
radiate heat!