Download Chapter 5 PPT 2 - Kawameeh Middle School

…continued
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Thermal Energy
potential energies
temperature
kinetic energy
https://www.youtube.com/watch?v=Hsu3Jo
XN-qU
The particles inside and outside of the house are
always moving.
- Inside where it’s warmer the particles are moving
faster than outside where it is colder.
Temperature Scales
Temperature is given in different
scales
You can measure temperature in three different scales:
Fahrenheit Scale (oF)
 Celsius Scale (oC)
 Kelvin Scale (K)

Fahrenheit
o
( F)
 Named after German Physicist
Daniel Fahrenheit
 Most common in the USA
 Freezing point is 32 oF
 Boiling Point is 212 oF
 180 divisions between boiling
and freezing.
Celsius
o
( C)
 Named after Sweedish
Astronomer Anders Celsius
 Most widely accepted around the world
 Freezing Point 0 oC
 Boiling Point 100 oC
 Centigrade scale – 100
divisions between boiling and
freezing.
Kelvin (K)
 International standard of scientific measurement
 Freezing point 273 K
 Boiling point 373 K
Absolute zero – No more
thermal energy (heat) can
be removed from matter.
(-273oC or 0 K)
 The lowest possible temperature for any material is 0 K
 If a material is 0 K the particles in that material
would not be moving and would no longer have kinetic
energy
 This is called
absolute zero
Converting Units
Celsius to Fahrenheit
 Formula :
Practice Problem:
What would 20oC be in Fahrenheit?
Converting Units
Fahrenheit to Celsius
 Formula :
Practice Problem:
What would 95oF be in Celsius?
Converting Units
Celsius to Kelvins
 Formula:
Practice problem
If it was 10oC what would it be in Kelvins?
Converting Units
Kelvins to Celsius
 Formula:
Practice Problem:
If it was 310K what would it be in oC
Measuring Temperature
 Thermometers are what we use to measure temperature
 Thermometers tell you the temperature of the matter
surrounding the thermometer.
How it works:
 The outside of the tube gets heated
 The particles of the liquid (alcohol) inside speeds up
and the liquid spreads out .
 The height of the alcohol indicates the temperature
Thermal Expansion
 Expansion, or increase in size of a substance caused by
heat.
 This occurs in all phases of matter when their
temperature rises.
 Knowing how molecules are arranged in a solid, liquid
and gas, how do you think thermal expansion will
occur in each?
Thermal Expansion
 Solid – Expand the least
 Liquid – Expands more than solid but less than gas
 Gas - Expands the most
Thermal Contraction
 A decrease in the size of a substance caused by
decreasing temperature.
 What happens if you take a balloon outside on a cold
day? Why (what happens to the particles)?
The balloon would decrease in size because the
particles slow lose thermal energy (which includes
kinetic energy) and come closer together.
Using Thermal Energy
 Remember:
 Energy cannot be created or destroyed
 Many devices transform energy from one form to
another or transfer it from one place to another, but the
amount of energy does not change.
Heating
Appliance
Thermostats
 A device that converts
 A device that regulates
electric energy into
thermal energy.
 Examples:
the temperature of a
system.
 Applies the properties of
Curling iron, toaster, clothes iron
 Most appliances get warm
when plugged in because
Some electric energy is always
converted into thermal energy
in an electronic device.
thermal expansion