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!