unit 3 heat & temperature
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Unit 3 Heat & Temperature. Unit 3 Topic 1-Using Heat. Using Heat For Energy. Since the beginning of time we have used for fire for a variety of things… Cooking Protection Construction Heating The list goes on …. Using Heat For Energy. How do you think our school is heated? - PowerPoint PPT PresentationTRANSCRIPT
Un i t 3H e a t &
Te m p e r a t u r e
Un i t 3To p i c 1 -
U s i n g H e a t
Using Heat For Energy• Since the beginning of time we have used for
fire for a variety of things…
– Cooking– Protection– Construction– Heating – The list goes on …
Using Heat For Energy• How do you think our school is heated?
• How is your home heated?
• How do you cook your foods at home?
Using Heat For Energy• The beautiful part about our world is that it is
constantly changing and technologies are improving
• Everything is being upgraded and improved for better efficiency and smaller ecological footprints
Un i t 3Topic 2-
Measuring Temperature
Measuring Temperature• What is temperature?– A number that tells you how hot or cold something is
• While this is the practical everyday definition science looks at temperature differently
• What about estimating temperature? – What do we do, often
without thinking to estimate the temperature of something?
Thermometers• What is thermometer?– Mechanical or electrical devices used to measure
temperature accurately• The first thermometer was invented around 1600
by Galileo who was an Italian scientist • The design was then improved about 100 years
later by making it more portable and using different liquids
• What are these thermometers missing?
Measuring Temperature• If you said “scales” you are a genius!• The other thermometers gave general ideas but
as we grew as a population and society and technologies improved we needed more accuracy!
• We needed a standard unit of measure
• Enter Anders Celsius!
The Original Duckface!
I wonder if this will
catch on?!
Measuring Temperature• The Celsius Scale is almost universal … *Cough*
America *Cough*• So how did he come up with this scale?• He used what was around him and made some
observations about it • What was that?– Water!
• So what do you think he did?
Measuring Temperature
Measuring Temperature• As smart as that was we need to remember one
important thing about water …• It is picky!• Changes in pressure and purity will effect water’s
boiling and freezing point • In Alberta are we above or below sea level?– Right, above sea level – How does this affect how we boil water?
• Water in Alberta actually boils several degrees less than 100oC!
Measuring Temperature• So what this caused scientists to do was go…
Oh my God where are your feet?!
What? Ahhh!!Who cares … what
we need to talk about it is
temperature!
I agree, my feet are now in the past and
this is present!We need a new
temperature scale!
That’s right, as scientists we need
to know the absolute coldest
temperature!
What do you think that would be Lord
Kelvin?
Ah you know I have been dubbed Lord Kelvin even though my name is William
Thomson!
Everyone knows, you don’t shut up
about it!
Well I am proud of it. Alright back to
work here…
…Carry the 1, factor in the sea level …
atmospheric pressure … aha!
12 … 23/2.34 + 9*Insert complexMath equations* …. = -273.15oC!
Has anyone ever froze something to
that recorded temperature?
No, but the math works out!
As my great math teacher Mr. Cox said
“You can’t argue math!”
So if we put this into a new temperature
scale…
…we call it the Kelvin scale!
Shotgun!
Shoot … wasn’t fast enough!
Also, we are calling the unit of measure
Kelvins! Boom!Ahh man!
Also the scale looks like this! Also,
because Lord Kelvin says so!
That’s a good looking scale right
there!Ahh! Who said
that?
Seriously Kelvin, for a smart man you need to get it together! I bet they teach this stuff in schools
later!
My legacy will live on forever!
Measuring Temperature• So we now know a lot about thermometers • Can you use the same type of thermometer in
any environment?• Actually you cannot … accurately that is!• You need your thermometer to have special
components for it’s specific use and these components are …
• Sensor– Material affected by the change in some feature of
the environment
Measuring Temperature• Signal– Information signal about temperature that is
generated and transmitted • Responder – Device (light, pointer, liquid) that receives the signal
and uses/responds in some way to it
• So what are some examples of different and unique thermometers?
Measuring Temperature• Thermocouple– Two different metal wires twisted together – When wire tips are heated they produce an electrical
signal that travels throughout the wires• *The amount of current depends on the temperature*
– This current is connected to a probe or a computer
– The current gets too high it can trigger valves, switches
– Unique for how high of a temperature it can record, normal thermometers would boil and break
Measuring Temperature• Bimetallic Strip– Two different metals joined firmly together – As it is heated one metal expands more than the
other and it coils more tightly – When it is cooled the process is reversed – The movement of the strip
can operate electrical switches – Used for example in air
conditioners, furnacesand fridges
Measuring Temperature• Bimetallic Strip
Measuring Temperature• Recording Thermometer– Uses a bimetallic coil attached to a long metal lever
that holds a special pen – The tiny movements of the coil translate to larger
movements on the pen– The pen traces a line up and
down along the spinning drum– The drum does 1 full turn
every 7 days so it can track weekly temperature changes
Measuring Temperature• Recording Thermometer
Measuring Temperature• Infrared Thermogram– Anything warmed than absolute zero gives off
infrared radiation (IR) – IR is similar to light but cannot be seen with the
naked eye– You skin can detect it though through touch (warm)– You can capture it on video using special cameras and
sensors – The colour and brightness of the image tells you
about the temperature
Measuring Temperature• Infrared Thermogram
Measuring Temperature• Knowledge Test
Is this video real or fake?