Heat and temperature

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Heat and temperature
PLS. COPY THIS TO YOUR NOTES!!!!
Heat- is the transfer or flow of thermal energy
between objects that have different temperatures.
-Heat moves from substances that are warmer (
more thermal e.) to colder substances(less Th.
E)
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• Thermal energy the total KE and PE of the
  particles in a substance ( s, l or gas ). The
  more particles there are, the MORE thermal
  energy.
• The greater the average distance between
  particles, the greater the potential energy of
  the particles.
• MORE MASS MORE TH. E.
• If KE is the same, the thermal E. can be
  different b/c the PE of the particles can be
  different.
• Temperaturemeasure of the average kinetic energy
  (speed )of the molecules in a material.(how fast
  or slow they are going)
• Thermometer- instrument to measure temperature.

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• The potential energy of the soccer ball depends
  on the distance between the ball and Earth. The
  potential energy of the particles of matter
  depends on their distance from one another.

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Lesson 1 LR2
Particles that make up liquid and solid water
have different potential energies, and therefore
also have which of the following?
A. different thermal energies B. different
temperatures C. different kinetic energies D. the
same thermal energy
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Now, can you do this? KE is to
____________________ as PE and KE is to
_______________________
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Bill nye on Heat
http//www.youtube.com/watch?vf1eAOygDP5s
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BP boiling point FP freezing point AZ
absolute zero
Temperature SCALES CELSIUS
KELVIN FAHRENHEIT BP 100
373
212   FP
0 273
32   AZ
273 0
-460
(ADD 273 TO GET k) (-273 TO GET C)

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Absolute Zero point at which an object has
almost no energy in it. Has not been reached yet
Have we reached it? No, not yet, however MIT
has come ridiculously close (within one
nanokelvin or .00000000001K of it) Source(s) http
s//www.youtube.com/watch?vTNUDBdv3jWI At some
level, there is always some heat being
released,keeping us from reaching it.
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Temperature conversions !!! How do we convert ºC
to K?

• K ºC 273
• 200 C ______? K
• How do we convert K to ºC

Problem
ºC K - 273
Problem 105 K ? ºC
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Temperature conversions !!!

• How do we change ºF to ºC ?
• ºC 5/9 (ºF 32 )
• or, (ºF 32 )
• 1.8

Problem 98.6 ºF ______ ? C
How do we change ºC to ºF ?
ºF ( 9/5 x ºC) 32 or, (ºC x 1.8)
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Problem 30 ºC ? ºF
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Temperature conversion problems to do

• Just do the ones that are
  circled in red
• do degrees Celsius and Kelvin
  problems first.
• 75 F __________ C
• 0 F __________ C
• 3. 98.6 F __________ C
• -10 F __________ C
• 45 C __________ F
• 30 C __________ F
• -10 C ___________ K
• 200 C __________ K
• 40 K __________ C
• 37 C ? F

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Temp. answers

• 75 F __23.9____ C
• 0 F _ -17.8____ C
• 98.6 F _ 37_____ C
• -10 F _-23.3___ C
• 45 C __113____ F
• 30 C __86_____ F
• -10 C __263___ K
• 200 C _473_____ K
• 9. 40 K _ 233____ C

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Units used to measure Thermal Energy ( Heat moves
it )

• Heat is measured in units called Calories or
  Joules (J)
• One calorie is the amount of heat needed to
• raise 1 ml(g) of water by 1 degree Celsius.

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• A calorie is a unit of energy. We tend to
  associate calories with food
• but they apply to anything containing energy.
• For example, a gallon (about 4 liters)
  of gasoline contains about 31,000,000 calories.
• Specifically, a calorie is the amount of energy,
  or heat, it takes to raise the temperature of 1
  gram of water 1 degree Celsius (1.8 degrees
  Fahrenheit).
• One calorie is equal to 4.186 joules, a common
  unit of energy used in the physical sciences.
• Most of us think of calories in relation to food,
  as in "This can of soda has 200 calories.
• It turns out that the calories on a food package
  are actually kilocalories (1,000 calories 1
  kilocalorie).
• The word is sometimes capitalized to show the
  difference, but usually not.
• A food calorie contains 4,184 joules.
• A can of soda containing 200 food calories
  contains 200,000 regular calories, or 200
  kilocalories.
• A gallon of gasoline contains 31,000
  kilocalories.
• The same applies to exercise -- when a fitness
  chart says you burn about 100 calories for every
  mile you jog, it means 100 kilocalories.
•  For the duration of this conversation, when we
  say "calorie," we mean "kilocalorie."

      Related Topics
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The JOULE is the SI unit used to measure the
amount of thermal energy. Developed by James
Joule. 1 calorie 4.19 J.
1 kilocalorie 4,186 J England and
other countries in Europe use the BTU.
(1 calorie  .00397 Btus.  1 Btu 
1,055 joules. 1 Btu  .252 kilocalories (kcal)
)
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Heat Transfer- Use smart bd slide show
also movement of thermal energy from a warmer
substance to a cooler substance. There are 3
ways in which heat transfer takes place
conduction, convection and radiation
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Video on heat transfer

• http//studyjams.scholastic.com/studyjams/jams/sci
  ence/energy-light-sound/heat.htm

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Convection simulation---A blob of potassium
permanganate shows convection currents in a
beaker of water as it is heated

• http//www.youtube.com/watch?va3BdBiSmlFUfeature
  related

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• Convection
• Heat is transferred in liquids and gases through
  movement of particles from one area of a liquid
  or gas (fluids)to another by up and down
  movements, called Convection Currents.

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• This cycle of cooler water sinking and forcing
  warmer water upward is an example of convection.

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Convection Currents in Earths Atmosphere
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2. Conduction heat is transferred through a
substance, or from 1 to the other by direct
contact of molecules. This mostly takes place
in solids, and liquids
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Conduction simulation
http//www.youtube.com/watch?v-UcBRveX_78feature
relatedhttp//www.youtube.com/watch?v-UcBRveX_78
featurerelated
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Calorimetera device that measures heat gain from
1 substance to the other. via conduction
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Thermal Insulators--- do not conduct thermal
energy or electricity well keep things warm or
cool Ex thermos, wood, plastic, comforter,
styrofoam, air, glass Thermal Conductors allow
thermal energy and electricity to flow through
them ex metals, water ,air, glass
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3. Radiation thermal energy is transferred
through empty space by electromagnetic waves. No
matter is needed.
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Review of thermal energy transfer
http//www.teachersdomain.org/asset/lsps07_int_hea
ttransfer/
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• Thermal Expansion
• Increase in volume ( size ) of a substance,
  caused by absorption of thermal energy as heat
  moves it.
• Contraction
• decrease in volume ( size ) due to loss of
  thermal energy

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When materials are heated, they expand,
and when cooled they contract. That is why you
see expansion joints (pictured below) on bridges
and parking ramps. That is on reason sidewalks
and roadways split too.The degree of expansion or
contraction depends on the material.One other
interesting thing when cooled, water will
contract until it reaches a certain temperature,
and then it actually starts to expand. This
effect is what keeps ice on top of lakes.
                                                  
                         

• Thermal contraction and expansion

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Thermostat device that controls temperature
with a bimetallic strip . Bimetallic strip
switch in a thermostat .
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Which has more thermal energy a bucket of water
at 50 degrees C or a cup of boiling water at 100
degrees C ?
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The amount of thermal energy a substance has
depends on the MASS of the substance, AND the
motion of the molecules!!! Ex 10 g of H2O _at_
90 degrees F is hotter or colder than 5 g H 2O
_at_ 90 degrees F?
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Problem if it takes 1 calorie to raise 1 ml
(g, cc) of Water 1 degree 1. how many calories
would it take to Raise 500 mL of water 2
degrees, if it was at 40 degrees Celsius? 2. How
many calories are needed to change 30 grams of
ice into water? ( HINT it takes 80 calories to
melt 1 g)
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Specific Heat---water has a HIGH specific
heat Ability of a substance to absorb thermal
energy. The specific heat of water is (1
cal/g/C) OR, 4,186J/kg/degrees C COPY
WATER HAS THE HIGHEST SPECIFIC HEAT OF ANY
LIQUID ON EARTH !
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Specific heat of some substances
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• When a material has a low specific heat,
  transferring a small amount of thermal energy to
  the material increases its temperature
  significantly.

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• Thermal energy can be transferred through
  radiation, conduction, or convection.

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• When a material is heated, the thermal energy of
  the material increases and the material expands.

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Lesson 2 LR1
Which term refers to a material through which
thermal energy flows easily?
A. convection current B. specific heat C. thermal
conductor D. thermal insulator
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Lesson 2 LR3
What term describes the transfer of thermal
energy by the movement of particles from one part
of a material to another?
A. convection B. conduction C. thermal
contraction D. thermal expansion
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Lesson 2 LR2
Which describes an increase in a materials
volume when its temperature increases?
A. conduction B. thermal expansion C. thermal
conductor D. thermal contraction