Hi I’m Gary for Expert Village. The next thing
we want to do is prepare the balloon to cover the jar. And what we need to do is cut the
balloon towards the bottom and we’re going to then spread it across the top of the jar
so we’re going to make a cut right down pretty much into the middle of the balloon. Now this
balloon should be a twelve inch balloon, they usually say on the packages the size and inches
of the balloon that you can blow it up to. And it’s very important, most balloons are
nine inches and this should be a twelve inch balloon. It’s a little bit bigger and it’ll
give you a more flexibility to put it over the jar, the mouth of the jar. And it should
be as flat as possible over the mouth of the jar. So we go ahead and spread it out and
cover the jar with it and we have to make sure we have some a little bit of room on
the sides so that we can we’re going to seal it by wrapping a string around. So we pull
it really tight around the mouth of the jar and try and get it as flat as possible. But
be very careful not to rip the balloon and this basically puts a really tight seal over
the jar. And what we’re trying to do is to create an air tight jar and measure the air
pressure from the outside as it sits on the balloon. We’re going to measure the weight
of that air pressure as it sits on the surface of the balloon and we’re going to be able
to tell which is heavier if the air pressure in the jar becomes heavier than the balloon
from the bottom will be rising up and that will affect our gauge or if the air pressure
from the outside is stronger it will press down on the balloon and that will also affect
our gauge in a different way. The gauge being the straw that’s going to be sitting on the
surface of the balloon. So that’s how we put the spread out the balloon we cut the balloon
and make sure that it is as flat as possible and that we have a very nice air tight seal
over our jar.