Please enable JavaScript.
Coggle requires JavaScript to display documents.
Nuclear Physics - Coggle Diagram
Nuclear Physics
History of the atom
Democritus was the first to theorise that everything was made of "atoms", meaning uncuttable and that they were the smallest things in existance
JJ Thompson discovered the electron and thought of the atom as positively charged with negative electrons embedded in it. This was known as the plum pudding model
Rutherford's experiment carried out by two of his students involved firing alpha particles against a sheet of gold foil.Through this, they found that 1 in 8000 bounced back (off of the nucleus) at over 90°. The nuclear model was recognised after this experiment.
James Chadwick discovered the neutron and created the quantum model with the nucleus composed of neutrons and protons while being orbited by electrons.
Finally Neil Bohr was the one to find that electrons travel at set distances,called shells which had a set number of electrons, giving us the Bohr model of the atom
Radiation
Alpha
Alpha decay causes the loss of 2 protons and 2 electrons, changing the atomic number by 4 and the atomic mass by 4
An alpha particle is made up of a helium nucleus, 2 protons and 2 neutrons. It is the most ionising type of radiation but can be stopped by paper and is most harmful at a distance of 10cm
Beta
Beta means a proton is gained, increasing the atomic number but not the mass number as it is a neutron which turns into a proton.
Beta particles are very fast moving electrons and when one is emitted the neutron changes to a proton to balance the atom and keep it stable. Beta radiation can travel 1 meter and cn be stopped by thin aluminium
Gamma
Gamma radiation is a short electromagnetic wavelength that is high in photon energy and isn't made up of particles
It can mostly be stopped by thick lead, with some getting through. In a vacuum it can travel forever
Ionised atoms
When a human cell is ionised it becomes danged. When the cells are repaired they copy the damaged cell and this continues. This is how cancer is caused
However cancer can be reversed through radiation through Chemotherapy which works by separating the affected area of mutated cells and destroying it
-
Fission and Fusion
Fission
Used in Nuclear power generators. Energy is generated by firing neutrons at plutonium atoms, which can absorb them. When the neutrons are absorbed they split, releasing an enormous amount of heat energy. The heat is used to vaporise water into steam, which turns the generators to create electricity.
When a plutonium atom splits, It releases other neutrons which are absorbed by other plutonium atoms. To help slow the reaction rates, Boron control rates (commonly made of graphite) which absorb the neutrons to limit the number hitting the plutonium atoms. The deeper the rods are the more neutrons they absorb and the slower the reaction rate is
-
Fusion
Only occurs in the sun. When 2 hydrogen atoms are forced to get very close under enormous heat and pressure they combine to create helium atoms releasing lots of energy
This, unlike fission leaves no nuclear waste
-
-