S-Cool Revision Summary

S-Cool Revision Summary

Take a proton and a neutron - find their total mass - combine them via nuclear fusion - take their new mass - and some has disappeared. !!??!!! We call it the mass defect. This mass has been turned into energy.

Consider matter as a solid form of energy.

"The energy released when the nucleus is assembled from its constituent parts."

Note: the value is often given per nucleon !!!

The most stable elements are those whose atoms need the most energy to separate them, i.e. those with the greatest binding energy.

Because iron is the most stable nucleus, it makes sense (in energy terms) for other nuclei to try to become more like iron.

So smaller nuclei will combine (and give out energy in doing so) to produce larger nuclei - more like iron! This process is called Nuclear Fusion.

Larger nuclei will split up to produce smaller nuclei (more like iron) and give out energy in doing so. This is Nuclear Fission.

You cannot simply look inside an atom in order to find how large the nucleus is. Instead high-energy particles are directed at atoms and arrays of detectors surround the target to find what sort of particles are scattered and where to. By looking closely at the data from the detectors physicists can discover much about the targets in question.

Nuclear Physics

E = energy, J

m = mass defect, kg

c = speed of light, ms-2