So, we’re braving the elements Brady, to
repeat the experiment that we did quite some time ago, so you will remember that we had
a very small balloon of hydrogen Match on a stick to hydrogen, big bang coming! Are you ready? Yep! Here we go! And the fact that we’ve come outside, might
actually give you an idea of what we are going to do, cause we are going to make it a little
bit bigger, so let’s go and fill a balloon. Alright, cool. Well, hydrogen, I think is very important
because, it is the simplest atom, it’s the atom, consists of a positively charged proton
which is relatively large and a negatively charged electron, that goes round it. Electric match? I think an electric match will go well on
that. Yep. Oh, look at the tension on the balloon! Hold it, I’ve really gone for it and blown
that one up. The tension! What happens is that hydrogen is reacting
with oxygen and H2 plus O2 reacts to form H2O and an oxygen atom and then that oxygen
atom goes on to react with another hydrogen molecule to make more water and the reaction
generates a lot of heat and that heat, heats up more gas to make it react faster, so you
generate more and more heat, so the reaction that begins quite slowly with the first few
molecules, runs away and that is why you get the explosion. So here we have a rather large balloon of
hydrogen, Neil is just preparing our electric match which we are going to attach to the
side of this balloon. And some of the biggest explosions in the
20th century, the Chernobyl reactor, the space shuttle that blew up when it was taking off,
were in fact explosions caused by hydrogen and oxygen. So we’ve filled up a balloon of hydrogen,
and I think if you look at the hydrogen balloon you will see that it is slightly larger than
those we have attempted before. Now we are going to try to detonate it or burn the hydrogen,
in the air by giving it a match and the match we are going to use is again an electric match,
which is connected to our detonator box. If you stick a pin in the balloon, the balloon
will burst because the rubber will break, but the hydrogen will come out and it won’t
react with the oxygen because the hydrogen is cool, it’s at the same temperature as
the air, but the reaction of hydrogen and oxygen like many reactions involves so called
activation energy, you have to put in a certain amount of energy to get it going. But once
you get it going, you get more heat coming out, than you put in to start it off. So, let’s arm the circuit, 5-4-3-2-1. That was more like it. Lovely! When Pete puts the match to the balloon, first
of all the match burns a hole in the balloon, and then the heat gets the hydrogen and oxygen
near the outside of the balloon and they start reacting and the heat then spreads through
the volume of the hydrogen and oxygen, faster probably than the balloon is bursting and
as it spreads through the temperature builds up and up and up because you are generating
so much heat. The reason that you hear a noise, is because,
it causes a rise in pressure which sends a pressure wave out through the air and it hits
your ears or the microphone on your camera. I honestly don’t know why you see any colour.
I suspect that the colour may actually be caused by the burning balloon which contains
carbon and is really like the flame on a candle. Because normally when you have a hydrogen/oxygen
flame you don’t see any colour at all. Alternatively, it may be some impurities in the gas, but
I suspect that what you are seeing in the fire ball is just the burning of the balloon.
The other thing which is really quite exciting about hydrogen is that in principle if you
heat hydrogen to really high temperatures, you can get two hydrogen atoms to fuse together,
or rather, it will not work with hydrogen, but it will work with a heavier form of hydrogen
which is know as deuterium where instead of a proton and an electron, you have a proton
and a neutron, which is a neutral particle, and an electron, and two molecules of deuterium
can fuse together to make one atom of helium which has two protons, two neutrons, and two
electrons and this produces a lot of energy. It is the basis of the so-called hydrogen
bombs, which are like super atomic bombs, but which require an enormously high temperature
to get the reaction to go. You can probably hear it hitting and fizzing
into the bottle there. There is great hope that in the end much of
the world’s energy crisis can be solved by doing this so called nuclear fusion of
deuterium to make helium which would produce energy extremely cleanly. So here, we’ll just tie it off, if my Welsh
hands can actually tie a knot on a balloon, ‘cause, you know we are all a little bit
bizarre. Deuterium gas, in all its properties, will
be very similar to that of hydrogen, of course it is denser, because it has a neutron as
well as a proton but it is still much lighter than air so a deuterium balloon will still
float up to the ceiling and make Pete look just as stupid as the hydrogen one. You’ve got to keep hold of it. Or you lose it Or you lose it, you know! I was thinking more of fusing it, that sounds
like a really big explosion we could do out the back. No! Fusing reactors are way beyond what Pete
can do unless he is a lot cleverer than I think. I got a balloon! I had a balloon of hydrogen! That is the second time you have done that! Now it’s going to go up there eventually
anyway!
This has been around for a long time, and the original run through of the elements is long over, however they keep putting up interesting videos that teach me new things weekly
I use these for those 5-10 minute fillers when we have extra time. And Vsauce. Vsauce rocks.