View source for Rutherford's Alpha Scattering Experiment

==Key Stage 4==
===Meaning===
[[Rutherford's Alpha Scattering Experiment]] was an experiment that provided evidence which disproved the [[Plum Pudding Model]] of the [[atom]] and later led to the development of the [[Nuclear Model]] of the [[atom]].

===About Rutherford's Alpha Scattering Experiment===
: In the '''experiment''' [[Ernest Rutherford|Rutherford's]] students ([[Ernest Marsden]] and [[Hans Geiger]]) fired high speed [[Alpha Particle|alpha particle]]s at a thin sheet of [[gold]] foil. A detector could be placed at different positions around the '''experiment''' which would make a small flash of light every time an [[Alpha Particle|alpha particle]] reached the detector. This could be used to find the path of the [[Alpha Particle|alpha particles]] as they passed through the [[gold]] foil.
: The path of the [[Alpha Particle|alpha particle]]s provided evidence to disprove the [[Plum Pudding Model]].
: If the [[Plum Pudding Model]] were correct then nearly all of the [[Alpha Particle|alpha particles]] should have passed straight through, unaffected, since the [[Alpha Particle|alpha particle]] is [[Positive Charge|positively charged]] while [[atom]]s should have an even spread of [[Electrical Charge|charge]]d [[particle]]s all the way through them. There should have been no [[Electrostatic Force|electrostatic force]] to change their direction.
: They observed that most of the [[Alpha Particle|alpha particle]]s went through in a straight line. A small number were [[deflect]]ed by a small angle and a very small number bounced off the [[Gold]] back towards the [[Alpha Particle|alpha]] source.
These observations led to a number of conclusions:
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| style="height:20px; width:300px; text-align:center;" |'''Observation'''
| style="height:20px; width:300px; text-align:center;" |'''Conclusion'''
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| style="height:20px; width:300px; text-align:center;" |Most of the [[Alpha Particle|alpha particle]]s pass straight through the foil.
| style="height:20px; width:300px; text-align:center;" |The [[atom]] must be mostly empty space.
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| style="height:20px; width:300px; text-align:center;" |Some of the [[Alpha Particle|alpha particle]]s were deflected by a small angle.
| style="height:20px; width:300px; text-align:center;" |The [[mass]] of the [[atom]] must be concentrated in an extremely small [[Volume (Space)|volume]] in the centre.
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| style="height:20px; width:300px; text-align:center;" |A very small number of [[Alpha Particle|alpha particle]]s came back in the direction of the detector. (Deflected more than 90°.)
| style="height:20px; width:300px; text-align:center;" |The centre of an [[atom]] must have a strong positive charge.

The [[electron]]s must not be in the centre of the [[atom]], they must be [[orbit]]ing the [[nucleus]].
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|[[File:AlphaScatteringExperiment.png|center|500px]]
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| style="height:20px; width:300px; text-align:center;" |This [[diagram]] shows the expected path of [[Alpha Particle|alpha particles]] through an [[atom]] in the [[Plum Pudding Model]] (Thompson Model) and what was actually observed, which led to the development of the [[Nuclear Model]] (Rutherford Model).
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