IB Physics Topic E.1.1 Historical Models and Experimental Evidence Revision Notes (SL/HL)

IB Physics Topic E.1.1 Historical Models and Experimental Evidence Revision Notes (SL/HL) | RevisionDojo

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The Geiger–Marsden Experiment and the Discovery of the Nucleus

Why Does Matter Behave the Way It Does?

Consider that you are playing a game of billiards, and one ball suddenly ricochets sharply backward after hitting another, as if it struck a hidden, rock-solid object.
This unexpected behavior mirrors what Hans Geiger and Ernest Marsden observed during their groundbreaking experiment under the guidance of Ernest Rutherford.

Their findings not only challenged the prevailing atomic model but also revealed the existence of the nucleus, a discovery that transformed our understanding of matter.

The Geiger–Marsden Experiment: Scattering Alpha Particles

The Setup

In 1911, Geiger and Marsden conducted an experiment to investigate the structure of the atom.
They directed a beam of alpha particles (positively charged helium nuclei) at an extremely thin sheet of gold foil.
Surrounding the foil was a screen coated with zinc sulfide, which produced tiny flashes of light whenever an alpha particle struck it.

Note

By observing these flashes, they could determine how the alpha particles scattered after interacting with the gold atoms.

Observations

The results of their experiment were astonishing:

Most alpha particles passed straight through the foil with little to no deflection.
A small number of particles were deflected at large angles, with some even rebounding toward the source.

Note

These results were unexpected.
According to the plum pudding model proposed by J.J. Thomson, the atom was thought to consist of a diffuse sphere of positive charge with electrons embedded within it.
This model predicted only minor deflections, as the positive charge was weak and spread out.

Rutherford’s Interpretation

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Note

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The Geiger–Marsden Experiment and the Discovery of the Nucleus

Why Does Matter Behave the Way It Does?

Consider that you are playing a game of billiards, and one ball suddenly ricochets sharply backward after hitting another, as if it struck a hidden, rock-solid object.
This unexpected behavior mirrors what Hans Geiger and Ernest Marsden observed during their groundbreaking experiment under the guidance of Ernest Rutherford.

Their findings not only challenged the prevailing atomic model but also revealed the existence of the nucleus, a discovery that transformed our understanding of matter.

The Geiger–Marsden Experiment: Scattering Alpha Particles

The Setup

In 1911, Geiger and Marsden conducted an experiment to investigate the structure of the atom.
They directed a beam of alpha particles (positively charged helium nuclei) at an extremely thin sheet of gold foil.
Surrounding the foil was a screen coated with zinc sulfide, which produced tiny flashes of light whenever an alpha particle struck it.

Note

By observing these flashes, they could determine how the alpha particles scattered after interacting with the gold atoms.

Observations

The results of their experiment were astonishing:

Most alpha particles passed straight through the foil with little to no deflection.
A small number of particles were deflected at large angles, with some even rebounding toward the source.

Note

These results were unexpected.
According to the plum pudding model proposed by J.J. Thomson, the atom was thought to consist of a diffuse sphere of positive charge with electrons embedded within it.
This model predicted only minor deflections, as the positive charge was weak and spread out.

Rutherford’s Interpretation

Definition

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Note

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Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Topic A - Space, time and motion5 subtopics

Topic B - The particulate nature of matter5 subtopics

Topic C - Wave behaviour5 subtopics

Topic D - Fields4 subtopics

Topic E - Nuclear and quantum physics5 subtopics

IB Physics E.1.1 Historical Models and Experimental Evidence Notes

Topic A - Space, time and motion5 subtopics

Topic B - The particulate nature of matter5 subtopics

Topic C - Wave behaviour5 subtopics

Topic D - Fields4 subtopics

Topic E - Nuclear and quantum physics5 subtopics

The Geiger–Marsden Experiment and the Discovery of the Nucleus

Why Does Matter Behave the Way It Does?

The Geiger–Marsden Experiment: Scattering Alpha Particles

The Setup

Observations

Rutherford’s Interpretation

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Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

The Geiger–Marsden Experiment and the Discovery of the Nucleus

Why Does Matter Behave the Way It Does?

The Geiger–Marsden Experiment: Scattering Alpha Particles

The Setup

Observations

Rutherford’s Interpretation

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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