Transcript Document

Temperature
 We
often associate temperature
with how __________ something feels
 Hot and Cold are terms that can be
___________________
 The same object can feel warm or
cool depending on the properties of
the object and the condition of your
body
Hot
Cold
Luke warm
Moving Energy
Changes Temp.
 Consider
an oven- turn the
dial on and heat is
delivered as energy flows.
When the dial is off, energy
stops flowing and
temperature cools
Temperature
Temperature is proportional to the
_____________ of atoms and molecules.
 To understand temperature, think of
atoms & molecules and _____________.
With more heat, atoms move more, have
more KE. When heat is removed, the
energy of theses moving atoms/
molecules is called _________________.

Internal Energy
 The
energy of substance
due to the ______________
of its component particles
and equal to the total
energy of those particles
Thermal Equilibrium
 The
state in which two bodies in
physical contact with each other
have ____________ temperatures
In time both liquids
Warm
will have equal
Beverage
temperatures
COLD
WATER



You can not find __________________ until
thermal equilibrium is reached
The temperature of the liquid in the
thermometer must _______________ the
temperature of the object being
measured. This must happen in order to
know the temperature
“You don’t read a thermometer until the
mercury/ alcohol has stopped rising/
falling”
Thermal Expansion
Things get _________ they EXPAND
 Things get _________ they CONTRACT
– Concrete bridges
– Rail Road Rails
– Power Lines
– Hot glass – cold water – cracks
 This is True for all solids, liquids and
gasses (some more than others)

Anomaly of Water

A strange thing happens
to water between
_____________: as it gets
colder, it EXPANDS-
GOOD NEWS FOR FISH!!
ICE 0°C
1°
2°
3°
4°
Thermometers
A
glass tube containing a thin
column of mercury, colored
alcohol, or colored mineral
spirits
 When heated, Liquid
_________________
Calibrating Thermometers
 To
calibrate thermometers
and to set a standard for
temperature we have chosen
water to be our bench mark.Not just any water – ______
_________________________
What About Fahrenheit
 We
must convert with the
following formulas:
– To find °F
°F = 9/5(°C) + 32
–
To Find °C
°C = 5/9(°F - 32)
Kelvin Scale
With °F and °C, often times you get
negative numbers; This is because
many things are colder than our
standard “________”
 To eliminate neg. values for
temperature, the ___________ was used
– 0 Kelvin is as cold as anything can get
– From 0 K, you can only go up

Kelvin Scale
 The
best thermal lab on
record has reached
0.0000001 K
 At 0K, the theory states that
___________ would cease to
vibrate
Kelvin Conversions
 To
find K
Kelvin temp = °C + 273.15
 To find °C
°C = Kelvin Temp - 273.15
Practice Problems 10A 1-5 pg. 3
HOMEWORK 2, 4, 5, 7, 9, 10 pg. 12
Section 10-2
Defining Heat
Read
and
Understand
Defining Heat
Heat:
–
–
–
–
Flow of _________
Moves in one direction, from ____ to
________
Symbol _____
Has units for energy (Joule)
(calorie, kilocalorie, dietary calorie,
Btu, therm)
Specific Heat Capacity
This is the amount of energy required to
change the temperature of 1Kg of a
substance by °C
Cp = Q/ mΔT
Q = m CP ΔT
Q = Heat (Joules)
m = mass (Kg)
Cp = Specific Heat (J/Kg°C)
ΔT = change in temp (°C)

Table 10.4 (pg. 7)
 Substances
take differing
amounts of energy to heat
up
– Water heats up _________
– Lead heats up ________
Calorimetry
 To
determine specific heat capacity
we do calorimetry
 For calorimetry always remember:
Energy absorbed = Energy released
Qwater = Qx
Cpw Mw ΔTw = Cpx Mx ΔTx
Latent Heat

_______________
Latent heat is the heat needed
to change the physical ______
of a substance (at constant
pressure)
SOLID
LIQUID
GAS
Latent Heat
Ice chest: mostly ice - little water (temp 0°C)
 Ice chest: mostly water - little ice (temp 0°C)
Heat was added to melt the ice but temp didn’t
change
 Boiling water: 100°C- doesn’t get hotter until
all water is gone, Even though heat is
continually added the water stays at 100°C
These examples show latent heat
All substances have this hidden heat (gold,
lead, aluminum, water, copper, ect.)

2 Types of Latent Heat



Both have the same units of heat (J) and
symbol Q
________________: the energy per unit mass
transferred in order to change a substance
from liquid to solid or solid to liquid
________________: the energy per unit mass
transferred in order to change a substance
from liquid to vapor or vapor to liquid
Formula for Latent Heat
Q = mLf/v
Q = Heat
m = mass
Lv = heat of vaporization
Lf = heat of fusion
Look at table 10-6
OVERHEAD
Heat Flow
____________________: this is how heat
flows through a substance. Some
materials conduct heat well. others are
very poor (insulators)
 Generally, metals are good conductors
of heat. Asbestos, cork, ceramic,
cardboard,& fiberglass are good
insulators

Heat Moves in 3 Ways
___________: heat moving through 2
objects that touch each other
 ___________: heating by movement of
fluids(liquids and gases). Involves
displacement of cold matter by hot

Heat Movement Cont…
 ________________:
electromagnetic rays carry heat
from everything above 0 Kelvin in
the form of waves. Nom medium
is needed for this- occurs in the
vacuum of space. Also, near a
campfire
Thermos
 Keeps
hot things hot, cold
things cold because it
minimizes heat flow
OVERHEAD
Clothes & climate
– Eskimo- Parka
– Arabian - Desert Dress
Section Review
HOMEWORK:
29, 32, 33 - 39