Experiment to Understand : Air Expands on Heating Video Lecture | Class 7 Oxford Science: Chapter Notes, Worksheets & Tests

hello I'm Jared back with more
experiments on the idea that warm air
rises heat rises so y-you can see that
heat rises with different experiments
that we've already shown you why is that
happening
so to show you that I have a bottle with
a balloon on top and what's inside the
bottle air is inside that bottle well we
can do something to that air we can heat
it or cool it to show you what's
happening and just so you can see what's
happening I put the balloon on top to
capture that air so I have a hot plate
I'm heating up a pot of hot water not
sticking my hand in and it's pretty hot
a plastic bottle when I stick the bottle
in the hot water it's going to heat the
air inside that bottle and you can see
almost instantly that this air is
actually rising well why is it rising
it's because the the molecules of air
are heated up and they're actually
spreading out they're spreading out
becoming less dense becoming lighter and
you can see all the air in this bottle
is expanding spreading out taking the
space up in this balloon wow it's not
gonna blow up till it pops but it is
expanding and as that air is heated it
expands and it becomes lighter than
everything else around it so it's taking
up more space those molecules are moving
around quicker bumping into each other
they need more space they're expanding
well now I have a bucket of ice water
I'm gonna slow those molecules down drop
it in almost right away that air is
collapsing condensing down you can see
there's no air in the balloon because
that air sinks it drops it's less dense
and all those air molecules are slowing
down coming tighter together they don't
need as much room wow it's almost
sucking the balloon into the bottom warm
air rises cold air sinks neat concept
thanks for watching