from early childhood
we can tell by touch
whether an object is hot
or whether it is cold
you won't even object
you bring it in contact
result object for instance aflame
if you want to call an object you're
bringing contact
was a cold object
when objects
but he did
or when they're called
and the temperature changes
then some of their properties change
and those properties are cold
thermo metric
properties
metric
properties
one very characteristic thermal metric
properties
most substances when you teach them
they expect
and when you called and they shrink
talk more about it later
if you take a gas in it
closed boy and you need it
the pressure goes up
that's a cinematic property
if you take an electric conductor
and you need it in general the electric
resistance will change
if you need to ireland bar
you would expect
and if you place it in contact with
another iron bar which is called
the one that is possible string
and the woman is cold
loaded up and we'll get longer
and this process will go along
up to the point
that the haslam will not get shorter
and that the coleslaw and will not get
longer anymore
and that is when the two objects as we
say i a m
thermal equilibrium with each other
and that is when the temperature
of the two objects
by the same
and so you can
the fine a temperature scale
looking at the link
open object
for instance he was a bar
so material
i planted in here
at length l
and i think there's a temperature bynum
on delta qty
and it gets longer
by certain amount to no avail
i could put the whole thing
in melting ice
melting ice
and i could say aha
like that if they are what
that i could put the whole thing
in the boiling water
and i do that
one atmosphere pressure
and then i say aha
recall that
we're going to help you
and those are my reference point for
mike
them but to scale
celsius
if just that
the idearc becuz
melting ice
which is now called zero degrees
centigrade and he used boarding point of
water
reporters
under the tree centigrade
was a swedish astronomer in seventeen
forty two he introduced this
temperatures ca
so you could make yourself
the plot no
of the temperature
for the domains of that bar
and you could say okay
undertows
degrees centigrade
if the length of the bar
yet but agree sent a great
if the length of the bar
del wong
and now you can draw a straight line you
can always go a straight line from two
points at one point here
at one point there
and you can define temperature
by saying
if my bar
has this leg
l okie
would be the temperature
so you can include rosalia scale
in this fashion
and they think in principle courts acts
like a
thermometer
also u demonstration of these
seventy
in greek means one hundred
and therefore
we also colby's ko often
centigrade one degree centigrade is
often called one degree celsius is often
pull
one centigrade
well reasoned that the the fights the
scale
from zero
to one hundred equal portions
sober colin degree centigrade degree
celsius
highlights
german scientists invented
the mercury thermometer
we'll talk about the mercury thermometer
a little later
in seventeen fourteen
introduced a bill
scale in this in holland at the time
that the most of the time
unused as his restaurant point body
temperature
which he called hundred degrees
fahrenheit
and he used a mixture of sports folds
and ice
at zero degrees
anita one of these two we are very
reproducible with you pick one person
temperature today maybe they live in
tomorrow person make a fever
but the one that depict what we did have
a little bit of fever
and so defined its killing that sent is
not very reproducible
and it has been redefined
now in such a way that
zero degrees centigrade
uh... this
period to read respond right
and hundred degrees centigrade
is two hundred and twelve degrees
apartheid
so if you converts
if you want to convert from finite to
send a great or the other way around
the temperature
inquired height
nine feet
i'm and temperature and celsius
club thirty two
if you take room temperature
temperature twenty degrees centigrade
i was growing up with
in europe everyone who to send the great
there
then you can see that
in terms of finite
that becomes
sixty eight degrees quite
nine fifth and twenty
if you thirty six
yet for the two
minus forty degrees centigrade
is the same minus forty degrees by her
that's where the two scales crossover
to almost the entire world uses set
celsius ko
it's part of our metric system
united states is one of the very very
few countries
who still lena roberts bubba runway
uses the grease part-time news really
pain that agrees are at least for me i'd
very little feeling for it
but does happen to know that the room
temperature sixty-eight because that's
the way except my
films that at my home that's about all i
can't think in terms of the grease fire
there's no limits too
high temperature but that is a limit to
the low temperatures is an absolute
zero
there's absolute zero below you which
you cannot go is about minus two hundred
and seventy three
degrees
self-abuse
and if you take assistant that cannot
transfer or energy
to any other system that isn't there
more contact with
then it is at that
what was possible
is it the way we define it
it's about minus
four hundred and sixty degrees
fahrenheit
and so we now have a philip scale which
was introduced by court calvin
the british scientists
he did a lot of research only
and he introduced the absolute scale
whereby he uses the
lowest possible temperature
at zero degrees
but increment in films or
increase of one degree uses the same as
the celtics game
so an increase of two or three degrees
kelvin at the same as an increase of
two or three degrees
centigrade
so if we don't compare different scales
celsius
weinhardt
and calvin
then twenty degrees centigrade would be
sixty-eight barnhart
and that would be
two seventy three point fifteen
plus twenty let's wrote it off and make
it through ninety three
and if we take
zero helping
then we would have minus two hundred and
seventy three point won't bite but let's
meet at all for now and it's
approximately minus portland six
we're almost always work was the grease
kelvin
in physics
and we'll discuss that in more detail
friday
most substances
expands
when you hate them
if we start with an object
which has length l
and i heated up
dougherty degrees
it gets warmer
bynum on delta l
and a delta al
and the expressing a very simple way
it is all fine
funds al how delta qty
and all parties called linear
expansion coefficients
and units art
one old hickory centigrade
or one over the greek alphabets thing
because it's its
increments that matter
values values for all file
defrag radio
give you some values ballpark
if you proper
i'll give you graph
i'll give you pyrex
argue in part
and i'll get used to you and they are in
unix
come to mind is fixed
third-degree centigrade
we will use some of them today
brasses about nineteen
poppers seventeen
pyrex
three point three in part
or point nine against you is roughly
twelve but there are many different
kinds of steel
in court
was a great invention notices it has a
very low expansion coefficient which was
very important
the nineteenth century even today
to make instruments
very precise like clocks
clocks are affected by the expansion
appears
and so deep into moving far which is a
a mixture
off sixty four percent
iran and thirty six percent nichols was
invented by
physicist do you own in eighteen
ninety-eight and for this discovery
you received the nobel prize
in nineteen twenty
tells you something how important it was
l or that has a very
flow expansion coefficient
if we use these numbers
that is look at the expansion of for
instance a railroad
we take a railroad
and we take a piece stretch of rail
which is jacob balconies
riddick stimuli ring visit the expansion
coefficients
and we compare a cold eight-mile
extremely cold but a cold day with a hot
summer day
a cold winter they minus fifteen degrees
centigrade
and hot summer day plus thirty five
degrees centigrade
so delta t
would be about fifty degrees
centigrade
philadelphia health
well that would be
twelve hundred into the mind of six
time spent in the spirit
i'm fifty
and that is about all point six meters
which is about sixty seventy
so what are you going to do with that
now
how is that souls
you real wants to get longer can get
longer
will start to boldly going this way
or sideways with everything these days
iterated his soul
is actually quite
temple
when you look at the whales
openings between them
they're very distinct
in about five centimeters you would walk
along the trail you can see them
openings
and if you make these openings
say five centimeters
then you would need twelve of them
insulted me too so every eighty meters
you would need
you can hear these gaps when the train
goes over these gaps
debate typical sounds
imagine wendy
real goes over it
years certain click
you can see them
and you can hear them and that's the way
they
correct for this expansion
and contraction
bridges
many kilometers long and they have of
course the same
problem of expansion in the way
that that is dealt with
also very clever
as follows
this is a picture that i copied action
from your book
pulled an expansion joints
there many of them
in bridges
and so what it allows the british to do
this
briefed up to speak
just to the temperature
there's a bizarre picture
whereby the claim is made
this railroads
became so ward because of an extremely
hot day
i trust me it'll go
hard to believe that it could be so bad
must have been
extraordinary fault as i mentioned is
the real cannot expands
at all it can do is eat a bulge
in this way where this way
whichever way is easiest with apparently
here the easiest way
is to go site please
they see a remarkable
destruction actually into an unexpected
high temperature
i have here brass bar which is about
thirty six
centimeters long
and i'm going to eat that brass part
you'll see you there too
the brass part
is right here
and we haven't we'll show you the
extension
even though it is extremely small
only a fraction of a millimeter
we can show that to you very easily the
way we do that this week
have some kind of an amplifier
it'd be
rolled
and i would put your hand
and david that
hands here
and it's easy to see that if you push
against it here
that these handle go like this
for very little extension he will give
you a large expansion
we do it twice
so we have two levels
and that is bizarre
i've yourself screw
and i can make i can move to bar in this
direction
i'm not making it longer what i can move
it and you will see what effect it's had
pets
if i move the bar one way
it goes off move the barbaric it goes
down
you can think of this is a thermometer
that will be seventy degrees as it is
not lead by heated up
that it will get longer and you will see
this
this and go up to find that
that goes
doesn't take very much
so we have brass
ellis thirty six centimeters
self-help
it would be about one millimeter
for temperature increases one hundred
fifty degree centigrade which of course
is trivial for us with that
blowtorch
still hot
i could call its
i could force it to cool it and then i
could even go below these points
here's what i was seventy degrees
remember the room temperature
i conclude with some
liquid and see whether i can get it done
quickly and even past this point
which would indicate that it is shorter
than it was
when the lecture started
he sees no shorter
now what you're looking at is only
something like
melanie even a little less
but we amplify it
and we show that
you quite uh... convincingly them
of very important implication
and application off
the expansion of medals is what we call
by metals
all around
afb
by met with the following
status trip here
like hell
all food in part
and have a lot of strip here
attached to it
so they cannot sleep relative to each
other
and that this be called for
and suppose i make
decisive
working example i make this thickness of
each one of them
too many
and i'm going to need it
eliminates increase in temperature delta
t
i'm not interested me knowing
how long the proper gets and how long
the in forget
but i'm very interested in knowing
the difference in the links between the
two
because got what was going to happen
when one gets longer than the other
something go to give
waiting to happen it bombed and they're
stuck together they can't sleep relative
to each other
what will they do
antigen for is not going to expand very
much but the proper will
if you're headed up
it will go
like this
and we'll see how many applications of
that
so what i'm interested in is really the
delta alva cooper
minus delco going for
that's what i'm after
and that is the all spot
of cooper
minus all clock
of in part
fund to help
and felt that the
what is the difference that matters
soldier defends is seventeen minus one
for the new sixteen
i'm tempted to my mistakes
fund to help
crime delta p
and if i take
a length of ten centimeters
and i'd increase in temperature
five hundred degrees centigrade
then there's a difference
but you can easily calculate
is point one six millimeters
over orange wild
very little
and yet
this one will curb
substantially
for those of you
lameta medicare oriented
i would advise you to they can attend to
calculate that
so you have
you assume that it is a perfect circle
that's a reasonable approximation
and so we have a daughter circle
which is longer
five point one six millimeters and you
know what
if i cancel
vital de beers
and i'm grateful that exercise
and you want to do that to perhaps and i
found that it's four minutes before the
easter mentions
formula news
that substantial
so the thing is being used for time was
that
you break and make a contract
heating system
which good for instance the as follows
he would be anywhere by metal
varies dramatically
plug it in the wall here you come to the
temple
usually either
and let it sit like that
and when it's cold
this is done
both girls
i think it works
and then to room temperature goes up
distorts the cruel
it breaks
and that's a thermostat that is the
basic idea behind if that was fast
thank you have the menu cards you have
them at home dance central
heating system
air conditioner
and he is a local the place
they also being used for safety device
if you have a gas hot water heater
in the pilot light in the flame of the
pilot light
is a by metal
and when that by metal is hot
you gasp l_p_s open
wind up by metal gets cold it shuts off
the gas fell
which is a safety defect
effect in europe old gas bulbs are
protected
that way by law
strangely enough not in the united
states
which is very surprising if i opened my
s felt at home with my style
the gas will just come out
just like that there's no prevention of
that happening
europe that's not possible
there's always a pilot light somewhere
with a buy metal
that sense is that there is a plainly a
bite to eat my pick ax
and at that point it out
the gas valve will be close
sobai metals can also be used very
effectively for safety devices
i have here by metal
website i believe we believe is aluminum
and the other side we believe is art
and when i need that
you will see that it starts to
get the idea
gregory read at the moment
very cool calm but g ideals from author
of course
white district
with the person
reese preparing with these
demonstrations in front of this way
boldly either that or wait
coffeemaker
and the coffee maker is designed in such
a way
that there is a by metal
at the bottom of the water reservoir you
hit the water reservoir
and when the warranty to certain
temperature
the by metal opens in the water comes
out
and go through coughing
i'd like to show that he was really cute
you're the coffee machine it's not
working anymore it's a very old home
but i want to show you at least that by
metal
this is that by metal strip
one of those in here your units when
it's hard enough
by medalists up
you can see there's a whole their this
is the whole
the water comes out with the by meadows
close implausible
with an amazing simple idea
the criterion for letting the war go
through a call for you simply
when the water reaches that temperature
close too boring
and you
have your by metal
control its sobai medals
in many ways control matters
films flaps in this case they act like
like adults
by metals can be used
a somewhat authors
in fact the one that you see
right here
is driven exclusively by
by metal
the book in the back
this for monitor
and almost wrote it to you shortly
because i broke my own open for you
then looks like this
as a portal
this end of the coral is attached to the
plastic casing
and here
is the repent
depended here
ran
this texas cannot know
i think it up
what will happen when i need a bit is
already a by metal
three-car related up it looked like it
even more it will prove even more
and when this one curled up even more
people going to give direction
so this is when the temperature
increases
and when it was gets colder even on
conqueror
and so here
kal and that's what the truth the whole
thermometers based upon
and in the back
so i broke one open for you
you know to make you see that court
we'll have it here
this is the part that is in the back
and this is that by metal
by metalcore lease at the bottom part
is that pop
and this is just the hand that is
attached to it
and then it goes into these
case
make sure that the it it goes in there
increased income but your
try to see if you see the coral
tightened up
with the core gets tighter
and when i make a temperature go down
artificially now by on
calling that quarrel
or the desire to know what we can do
is weekend
actually heated up
have to set the temperature of whatever
we can get it now
about seventy degrees in the room
supplements
eyes close enough
it is finite what a terrible failure and
by the way you also see some civilized
scale where you see so centigrade
in addition to
the fine print
so it's close enough it's a little bit
over seventy
and i can now
make sure that these stock
to lead to the case
i think he did
when i need it
by metal tightens up more and when i
blow air over it i can actually make a
cool a little aspirin ruled otherwise
so simple as that
very simple device
the by metals have many many
applications
but most apt
eager dormitories
of your heating systems
and also perhaps will be
air-conditioning systems
almost all have a core like this in
their was an extremely ingenious device
it has a coral
and at the end of the portal
is a bill blass tool
twenty one seventy two large
and his mercury inside
so the court is like this
by metal
and at the end here
is a glass container
and it's a mercury
mercury's here
on this site because notice the way i
feel free to go
mercury rules to the left
and they are here to why isn't that
requires one here
and one year
which go to the heating system
and so when the mercury is here which is
a good conductivity
the heaters on
motorola gets warmer and warmer and
warmer
and by metal will tighten up
we'll call even more
until the comes a time that these
blasting
we'll go like this
and the mercury
rolls out
and the mercury rules out
use the mercury
these contact here
open
and he will stop
that that almost every room
ferries genius device
now i want to
moved from
media expansion coefficients
two cubic expansion corporate
i believe these numbers there because i
will need them later on
but no i can't abroad also material
want to discussed before you mean creeks
not just the length
but the volume increase
so here i have a
solid material
let's make it simple all sides l
and uh... increase it by
an amount of temperature delta t
well
the old volume is help you
and then i'm going to increase the
temperature by delta peaceful all the
sides will get longer
by monday or fail
and soda new volume
will be al
kalispell file
buy-out
this can also be written as l
refitted
i'm swamped
was dealt iol
over al
from the power three
thinking right
well perhaps you remember or at least
you should remember
that one clas acts
with apollo and
and kato taxes much much more than the
bomb
is approximately one pathetic
we view is that before
when we discussed the bushes
lights on received stars
vehicle to binomial
carries binomial expansion is really the
first order terms of the fairly
expensive
if he were to make some politically
correct
equals all point oh five
and you calculate
the exact value
which a calculator
you would find one point
wonk like eight
if you do it this way
you'll find one point won't quite very
close
approximation is better than one percent
so i will use the same approximation
here
and so we're going to get
l two thirds
i'm swamped
delta l divided by l
so that it outwitted
cluster three
delta l
health credit
so the difference
in terms of delta p
the old holy moses
and equality included dot open
photocopy
is the difference between the two
and three
pehle parallels quiet
but i don't adele payroll
because all pop
finds al i've got the people
so i can substitute a two-year and so i
find the delta qty
equal three altaf
find helped create
times alvin is el q
i dealt with people
but al q wealthy old volume
and so i know fine
the delta v
people free all part
ideal volume i've got a p
and this one
is often called beta
data is cubicle
expansion coefficient as opposed to the
media one
so you will table a big deal
b_y_u_ talking about beta because
if we have the values fall far
all we have to do if we go to a volume
to make that
beta three all planned we are in
business
well when you have liquids
general
you don't find in the tablespoons cooper
so when you do with recruits for
instance
mercury
which is the one
that i want to use today
then you find
that the
schulich expansion coefficient eighteen
i'm tempted to my next part
retreat and the great
by competitors pyrex
you have to take three times is value
so that's very roughly ten to two months
fire
burdick disintegrate
and so now
you begin to smell the idea
open mercury
for a moment
i put some mercury
in pyrex glass
and the pirate class is not going to
expand very much
the mercury real
then the mercury
which is in an enclosed environments
we'll have to expand
and expanding to michael monitor
and that's the way
let me read to temperature
so he was a glass to which is very very
narrow
only disclosed here
let's say the radius here
could donate ope pulled one millimeter
your tour of the wire
mercury
they're working example
and suppose we take
on cuba kennedy
just simple numbers
this one to show you the the basic idea
behind at the moment
i'm going to increase the temperature of
this
mercury
they buy ten degrees
delta t
and agree centigrade
so how much will this volume expand
well-built upkeep
uh... nichols bay dot
eighteen content to the minus fitz
funds the volume which is one cubic
centimeter let me just point to volume
in their you may want to do it in cubic
meters early for that to you
arkadelphia
you'll find
if the expansion in terms of cubic
centimeters
is all points
oval
one eight
cubic centimeters
if you're adrian cubic centimeters
but you can do
that you get to answer also and continue
to support will always
have to work and chaos
fotis is an extraordinarily small
increase in terms of his volume
however
the pyrex
is not expanding at all he can just
forget that for now
you work out a date on what you did
prime but in the eighteen progress
so defected into battle get fitted a
larger
of course is important but i was
ignoring it for now
and so i will this assuming that all
these mercury
will be driven up here
and so we have been working with them
changes in tight
bynum on delta h
and if it is a
to did a radius point one ninety two s
then this amount of mercury must be the
same time
despite our squared
i'm delta h
which is the boy a m
of the new call umc increased into
called
until you
thank you point one million is
and you'll find the delta h
for this example that i chose
is
five point seven seventy
that's huge
it's very easy to see for ten-cent from
the greek integrating
increasing temperature
it's five point seven seventy
so for one degrees centigrade
you would get
six million very easy to see
so that's the idea
mercury thermometer
uh... i have to work with mercury
thermometer it would be a very hard to
read
but i have one here
to medical won't
just aural
not to be confused
and i can stick it in my mouth
much of our temperature
we can just tell you
if you're free work for me to show you
want to have in my office
which also worked on vicarage
deformed
so this won't
easy-to-read liquid
so that we have the right like setting
you should go off
lucida red liquid
it is
and also notice
editors degrees finite which is
unfortunate
but helping
when the temperatures here at least you
know what you're going to get all right
well that's it so when u thirty two
thirty to five must be here
snow
and this makes you feel good
you know just in case you don't remember
i could heated up
her
or should be careful when you read about
you don't go too far because the top of
the from woman to his clothes
indicated a mercury thermometer there is
back in here
so if you when it was a kid i what to do
this
victory medical for moment of my parents
and heated up with a hairdryer and then
it would just burst through it it would
break the glass with expansion issue
which the force
they were just pop off at back and say
nothing
and that can happen with this too
who doesn't have an opening is not open
is too closely
you've got to be
quite careful
there is a technique which is cold
shrank fifteen
and shrink sticking
support
you have a piece of metal
let's take just
solid cylinder isn't working example
and
gathering
the ring could be
itself is still under
but this one is opening
smaller than this
just a little smaller purposely make
that way
just a little spore
unique this one
expands
and he put it over your will fit
and the united states it cools and hips
i can to tell about school shrink
fitting technique which is often use
something to show you when you which is
the opposite of shrink fitting
i have a ring
i'll show you shortly
the screen there
and that's made of brass
and i have a bull
go through there
just barely but it go through there
and then i would meet up this bull
and then it won't go through there
so if you reversed but at least you get
the idea
and then if you wait
and it cools
where you can get in contact with each
other
this one will call
and this one will
got warmer so
you catch to work with one stone this
one will shrink
at the same time this one will become a
little larger
and soda and clearly it will
falls through
and that's the idea
let's try that
at the best liking that weekend
onto the circumstances
and seems to me
use of the ring
and here is that breast bull
go through it quite easily
droplets
horizontal now
and then i will start heating up
baseball
can be too close to the rain because
then the ringo also
dvd
and then of course
it good to have the same temperature
spendable will still go through
now doesn't want to go through
we would like that and we'll see what
happens
so it's a real no expand a little
good guess color
and the ball will shrink a little
because it gets colder
and it shouldn't take too long
portable to be able to get through
line-item both with ruth
the torch
and of course they will always be able
to
hoof whichever
you've got
so if i take the boat
but it was expanded
it for crack
there is no different
extension likely bipedal
and we're working
people would be able
sony when i
hit the ball and offering
but you get the effect
will get through
may actually get to know still get
what i've left out
of my discussions with you
is water
why have i not mention to you
what is the
expansion coefficients a cubicle
expansion coefficient water what it is
so important in our lives
well there's a reason why elected out
because there's something very special
with water
if you take twenty degrees centigrade
warmer
and you call it
it's rick's normal behavior
as a positive value
but when you reach four degrees
centigrade and you go all the way down
to zero
it doesn't ring expense
so in that range from zero degrees
centigrade to four degrees centigrade
wada has a negative value pulpit beta
when you need it
shrinks
when you call it expects
that makes water
extremely unusual
but it's great for fish
because it means that one oh four
degrees centigrade has the highest
possible density
higher density then twenty degrees
and a higher density dated zero degrees
and so when you do we do the palm trees
the highest density water goes to the
bottom
that's wide awake that's the way that
speech can survive while they're
becoming deep freeze fish right there
they can't swim
so most of the palms in the winter
bottom layers
are for the treatment
safely from the freezing point
when you melt
solids
and he becomes a quick and almost all
cases
the liquid expects sort of natural sodas
so it's the sink into the quit if you
take crystals
they sink
in their own weekly
but not what
what a nice are very anomalous
if you take water
at zero degrees
and your creativity becomes ice crystals
express
and the expansion is enormous because
the density of artists
the state
percent lower than the density
what does the devices or point nine two
grams per cubic centimeter don't work
the definitions one
this is what i can boost in the winter
when they please
optiplex three state people have water
pipes
you'd outside walls
it cool
it frees pipes burst because the ice
expects
they're not aware of happen in the
spring when the water melts when the ice
melts
all of a sudden
they have a plot
because the pipe first this is why the
titanic sank
because eyes
floats on water
ice has a low density
without ice
floating no icebergs this is why you can
speak on poems
because ice so will the density and
water supplies floats or more
the best way that i can demonstrate to
you that ice floats is to treat myself
give myself a colossal something
today it will be
apple cider
and ideas of ice cubes
and i put some ice cubes in here
and that quote
if you don't believe it
political
okay enjoy your
we can't you know we still have a
lecture on friday
