Fermi’s initial experimental observation of nuclear fission (2 Viewers)

[cutemouse]

"describe Fermi’s initial experimental observation of nuclear fission"

What exactly does this dot point involve? CSU refers to the pile he built in his university, whilst Jacaranda refers to some experiment of bombaring Uranium with beta particles...

 

[Dumbledore]

our school hasn't got that far, but from what i remember from the tsfx, it was the bombarding of Uranium with neutrons, this was an attempt to discover elements with higher elements

it would work like U238->U239->U240 but that becomes unstable and thus undergoes beta decay: U240-> N240+electron + anti neutrino
where N is neptunium(forgot symbol), beta decay doesn't change mass but a neutron becomes a proton + electron which will create a higher element

if an element undergoes beta decay and spits out an electron, an anti neutrino also comes out in order to conserve momentum, energy and spin

if it undergoes beta decay and spits out a positron, a neutrino comes out instead

and thats all i remember from tsfx, it was only a 3 hour lecture for the entire Q2Q so it might be a bit dodgy missing parts

 

[youngminii]

Lol Dumbledore, bit dodgy there.. You fed some incorrect + irrelevant info and didn't answer the dotpoint.. You barely described Fermi's inital observation, you led on to some random stuff and the dotpoint asked for nuclear fission. Fission is the splitting of an atom into two smaller atoms, not beta decay.

Fermi's initial experimental observation was the Uranium bombardment, the pile he built in his university is a different dotpoint.

Fermi bombarded lots of things with Neutrons and one day he had the idea of bombarding a Uranium-238 atom. When he did so, he noticed that the resulting matter had less mass than the original matter! He didn't know exactly what he was seeing and thought that the Uranium-239 was becoming Plutonium-239, which was partially true. It was later realised that the missing mass (now called mass defect) had turned into energy, by Einstein's equation e=mc^2.
What was actually happening was that the Uranium-238 atom absorbed the neutron becoming Uranium-239. This is an unstable isotope and it underwent beta decay into Neptunium-239 and another beta decay into Plutonium-239. It then underwent nuclear fission into smaller atoms, such as Barium and Krypton. It is important to note that Fermi initially didn't know he was observing fission, and that when he repeated his experiment, different levels of energy were being detected. This is because when Uranium-239 undergoes fission, it can split into different pairs of elements.

Btw that's from memory so don't blame me if I'm wrong

 

[darkchild69]

Fermi tried to extend the periodic table. He bombarded what he thought was Uranium-238 with neutrons and produced Uranium-239 which underwent beta decay to form elements with a higher atomic number than uranium i.e. neptunium and plutonium. Fermi observed several other elements that were different from those transuranic elements above because they emitted beta particles and had different half-lives. Fermi could not fit these elements to the periodic table near uranium, which should be possible if these elements were products of beta decay of Uranium-238.

It was later found that these elements had atoms that were much smaller than uranium and belonged in the middle of the periodic table. Furthermore, the uranium that Fermi used was a mixture of uranium-235, which could undergo fission, and uranium-238. Therefore, Fermi had observed fission, but failed to realise this.

 

[zhangy]

weird, in dotpoint, it says that his initial experiment was stuff with ping pong balls and trying to simulate a nuclear reaction
is this correct or was is it?

 

[cutemouse]

it says that his initial experiment was stuff with ping pong balls

:S What drugs are you on?

And btw, Fermi didn't actually do this experiment initially, so it's a badly phrased dotpoint.

 

[zhangy]

:S What drugs are you on?

And btw, Fermi didn't actually do this experiment initially, so it's a badly phrased dotpoint.

oops, i meant in the dotpoint book, they dont have anything about his test in the squash courts
just ping pong balls

 

[Melongo]

weird, in dotpoint, it says that his initial experiment was stuff with ping pong balls and trying to simulate a nuclear reaction
is this correct or was is it?

LOL hey, i know exactly what you are talking about!
i was lookin at that answer yesterday from dotpoint physics... the author seems to be implying that he actually did set up all those mouse traps in order to demonstrate that effect..

 

[kamelover]

LOL hey, i know exactly what you are talking about!
i was lookin at that answer yesterday from dotpoint physics... the author seems to be implying that he actually did set up all those mouse traps in order to demonstrate that effect..

Yeah i get what you mean... i have an assignment on this and i'm really not sure of what to write if i get that in the trials or hsc

is it safe to bet on writing both down?

 

[cutemouse]

Um, as stated, Fermi didn't actually observe the experiment...

I think my teacher did say that it was the experiment he setup at the squash court... don't rely on that though, it's memory from last year and I haven't revised my notes.