we started uploading periodic videos ten
years ago we never thought it would go
on for more than a few weeks but here we
are ten years on and Brady's allowed me
to choose my favorite ten videos as long
as I don't talk about them too much
number one I think video of rubidium
Neal's ingenious apparatus for smashing
a vial of rubidium and dropping it into
water containing an indicator
it's really good I think it typifies his
ingenuity with operators our enthusiasm
for these videos and the unexpected
things that we learn we didn't expect
rubidium to react so strongly number two
the accidental reaction where I poured
potassium permanganate it's purple into
hydrogen peroxide which is colorless and
the purple color just disappeared and I
went on and on and on pouring it and the
color just kept on disappearing it so
this is actually much better than I
intended because I was going to make it
purple and make it go clear and here you
can see I'm pouring in the purple
solution and it's disappearing I've
never done it before haven't got it to
work so well since it was an absolutely
wonderful demonstration number three the
video that made me look really stupid I
was doing a reaction of chromium
trioxide with ethanol produces a huge
flame and after the flame and as the
smoke was going up Bradley asked me
whether I'd arranged for the fire alarm
to be switched off I said yes you can
smoke alarm off yep you forgot to switch
it up
number four pumpkins for Halloween I
smashed the pumpkin with liquid nitrogen
Pete and Neil did the thermite reaction
in a pumpkin
hunting went white hot molten iron came
out my grandson has watched it many many
times
come along Martin when you think you're
hard enough we number five was one of
our very first slow motion videos it was
prompted by a viewer who suggested we
should let off a mixture of hydrogen and
oxygen in a balloon try burning a
balloon filled with a proper mixture of
two parts of hydrogen and one part of
oxygen so we compared a balloon with
hydrogen and a balloon with hydrogen
oxygen
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number six many people ask me how I
thought of making periodic videos
it was Brady who thought of the idea and
the video he made for the BBC really
explains how the idea came about and
what we've done for all his celebrated
work as a research chemist and
university professor Martin Polyakov
didn't become a celebrity till he got on
the Internet number seven is hammering
red-hot platinum we made this video at
the Johnson Matthey platinum refinery
and I could hardly believe my eyes as
they hammer the platinum to make the bar
thinner it gets hotter and hotter and
hotter and I've never seen such a
wonderful demonstration of converting
mechanical energy into heat number eight
is an experiment I've always wanted to
see done dropping heavy ice that's
frozen d2o
into ordinary water to see if it would
float and it was amazing and I'm hoping
it sinks it sank but then it rose up
again and I think now this was due to
the density of the water but I came up
with a different theory at the time
number nine was a video that I also
wanted to see which was putting flesh
into hydrofluoric acid HF which
dissolves flesh we couldn't use human
flesh so we used a chicken leg and I've
never seen anything looking as dead as
the chicken leg after it had sat
overnight in hydrofluoric acid number
ten is perhaps my all-time favorite
video it was our first video about
element 108 hassium and brady recorded
me saying that i knew nothing about
hassium and asking whether we should
make something up assume i knew nothing
about her soon should we make something
up however the power of the periodic
table
is that by looking at the periodic table
I can say well it's chemistry's got to
be a bit like iron now the really
interesting thing is that research
that's been done in the last few years
since we started periodic videos
suggests that with these really
super-heavy elements you may not be able
to predict their properties by looking
down the periodic table because of
relativistic effects in the atoms make
them behave differently from what you
might expect I would be really
interested to hear from you perhaps in
the comments which are your top 10 of
our videos because it's really nice to
be reminded of some of these videos and
I hope you will enjoy watching them
thanks so much for watching if you'd
like to see full-length versions of the
videos the professor listed I'll have
links in the description and here on the
screen including a playlist so you can
watch them all in order if you'd like to
know what my top 10 is I've also made a
video about that and I'll also put links
to that in all the usual places thank
you so much for watching over the last
10 years and here's to 10 more
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