Kind: captions
Language: en
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when you touch an object and it feels
warm or cold what is that really telling
you about the object here I have a metal
hard drive and a book and I'm going to
ask people to compare their temperatures
which one do you think will feel warmer
the book or the hard drive the
temperatures yeah tell me if one is
hotter or colder or if they're the same
temperature how do they feel uh this is
slightly cooler than this one yeah oh
that's warmer yeah way warmer yeah
agreed I'd say the hard drive is a lot
colder than the book um I don't know cuz
the books got more
knowledge why do you think that is
Metal's normally a little bit chiler if
you leave it in a colder temperature
well what if I said that they're both at
the same temperature what would you say
so you're lying but really I think
you're lying yeah oh jeez well maybe the
way I could prove it is I have an
infrared thermometer what do you think
we're going to see it's it's I think
science might be to answer that and I'm
not a scientist I a prediction for me I
still think that that that's cool though
would you bet me money I don't because I
don't have any cash to yeah let's
measure the temperature of the book okay
what do you see
19.0 okay measure the temperature of
that
19.0 all right well now I believe I'm
trying to actually figure it out
actually trying to figure out why there
would be the same temperature no didn't
they didn't feel the same temperature
though so why does that feel colder if
they're basically the same good one you
the answer well I'm coming to you guys
for answers we're we're creatives not
intellectuals well create an answer for
me I'm not a scientist come on you tell
me well I'll try to answer that question
with another little experiment here is
an aluminium block and ooh nice and cold
a plastic block yeah how do their
temperatures compare completely
different completely different much
colder yeah yeah yeah this actually
feels colder let's take this to the next
level I'm going to put an ice cube on
both
plates what are we going to see well I'm
guessing it would stay
solid on this one and melt on this one
so it's going to melt on the plastic but
stay solid on the aluminum yes but I'm
Maybe I'm Wrong that one will melt more
quickly than on the aluminium block you
would think so think they're colder yeah
cuz it's cold I think they're going to
go the same all right so we put an ice
cube on each of those blocks what are
you seeing well it is melting a lot
quicker on the aluminium I God it's
melting this is melting quicker than
than that one even though this is
aluminium that's plasty so which one
felt colder that one how does that make
any sense I have no idea you know could
aluminium be bad for the environment how
would aluminium be bad for the
environment well it's thoring out the
ice a lot quick so you want the answer
yes please please it's about thermal
conductivity right the rate at which
heat is transferred from one object to
another so when you felt these blocks
originally I know this one felt a lot
colder but you know from the other
example we did that they must both be at
the same temperature cuz they both been
outside for a while we see that the
aluminium block is melting the ice
faster than the plastic BL because it's
conducting the heat to the Ice Cube
faster with the plastic Block it's a
worse thermal conductor so heat is being
transferred less quickly to this ice
block and so it's staying ice okay I
believe you mhm makes sense yes
definitely you know in our first example
the hard drive felt colder even though
it was at the same temperature roughly
as the book and that's because the
aluminium conducts heat away from your
hand faster than the book conducts heat
away from your hand sure that seems
logical which makes the the hard drive
feel colder and the book feel warmer so
when you touch something you don't
actually feel temperature you feel the
rate at which heat is conducted either
towards or away from you think about
this next time you hop out of the shower
in winter it's much nicer to stand on
the bath mat than on the tile beside it
not because the bath mat is warmer but
because it conducts heat less quickly
away from
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you