Electromagnetic induction and the principles behind generators and transformers.
NANOSCIENCE HISTORY
Michael Faraday and the Birth of Colloidal Gold
Long before the words nanoparticles or nanotechnology entered scientific language, Michael Faraday was studying something extraordinary: ruby red suspensions containing particles of elemental gold too small for the instruments of his time to see directly.
His experiments with what he called divided gold became an important early chapter in colloid science and modern nanoscience.
1857
Landmark Publication
Ruby Red
Gold Colloid Appearance
Light
Used to Reveal Particles
150+ Years
Historic Samples Survive
THE BEGINNING OF GOLD NANOSCIENCE
Why Faraday’s Gold Experiments Still Matter
Faraday’s gold colloids are among the earliest scientifically documented metallic gold colloids and one of the clearest bridges between nineteenth century chemistry and modern nanotechnology.
At the Royal Institution, Faraday prepared ruby coloured liquids containing finely divided gold and studied how they behaved when exposed to light. Some of those historic samples have survived for more than a century and remain important scientific artefacts.
Faraday could not see the particles directly. The instruments available to him were not capable of resolving structures at that scale. Instead, he used colour, light scattering and careful observation to reason that the liquid contained extremely small suspended particles.
THE SCIENTIST BEHIND THE RUBY LIQUID
Who Was Michael Faraday?
Michael Faraday was one of the most influential experimental scientists of the nineteenth century. His work helped shape modern electricity, electromagnetism, electrochemistry and experimental physics.
He is best known for electromagnetic induction and the principles that made electric motors, generators and transformers possible. But his experiments with finely divided gold also place him close to the beginning of modern colloid science.
Faraday had an unusual ability to use visible experiments to reason about invisible physical behaviour. That skill became essential when he began studying gold particles that the instruments of his time could not directly resolve.
His work helped formalise the relationship between electrical charge and chemical change.
His field concepts changed how scientists thought about invisible forces and physical interactions.
His divided gold experiments revealed that materials can behave differently at extremely small scales.
THE PHYSICS OF COLOUR
Why Does Colloidal Gold Turn Ruby Red?
A solid piece of gold appears metallic yellow, but when elemental gold is divided into extremely small particles, its interaction with light changes dramatically.
At the nanoscale, electrons at the surface of the gold particles can respond collectively to incoming light. This optical behaviour is associated with what scientists now describe as localised surface plasmon resonance.
The exact colour of a gold colloid can vary with particle size, shape, surrounding liquid and the degree to which the particles remain separated. Under suitable conditions, finely dispersed gold can produce the characteristic deep ruby red appearance that fascinated Faraday.
Gold behaves differently when divided into particles at extremely small scales.
Surface electrons respond to incoming light and influence which wavelengths are absorbed and scattered.
The resulting optical response can give a stable gold colloid its characteristic ruby red colour.
INSIDE FARADAY'S EXPERIMENTS
What Faraday Actually Investigated
Faraday's importance was not simply that he produced an unusual coloured gold liquid. He systematically investigated how finely divided metals interacted with light.
His experiments explored different preparations of gold, compared their appearance and examined how the material behaved when light passed through it.
1857
Philosophical Transactions
THE BAKERIAN LECTURE
Experimental Relations of Gold and Other Metals to Light
Faraday presented his investigations into the relationship between finely divided metals and light to the Royal Society. His work described gold preparations whose optical properties differed dramatically from ordinary bulk metal.
An Experiment Built Around Observation
Without electron microscopes or modern nanoparticle analysers, Faraday relied on controlled preparation, comparison and optical observation to investigate material at a scale he could not directly resolve.
01
Prepare the Gold
Faraday produced finely divided gold using several experimental approaches, creating preparations with different colours and physical characteristics.
02
Observe the Light
He examined how light was transmitted, reflected and scattered by the preparations, using optical behaviour as evidence about the material within them.
03
Compare the Results
Changes in preparation produced changes in appearance. These comparisons helped Faraday connect the physical state of the gold with its unusual optical properties.
WHY THE EXPERIMENT MATTERED
Faraday Was Studying a Scale He Could Not See
The individual particles were beyond the direct resolving power available to Faraday. His achievement was therefore one of experimental inference: using measurable changes in light and appearance to investigate the physical state of matter at an extraordinarily small scale.
FARADAY'S TOOL
Light became a way of investigating matter that could not yet be
directly imaged.
THEN AND NOW
What Faraday Observed, and What Modern Science Later Revealed
Faraday's experiments were remarkably advanced for their time, but the scientific tools available in 1857 placed clear limits on what he could directly measure. Modern instruments later gave scientists access to details that Faraday could only infer from behaviour.
Behaviour He Could See
- Colour changes in different finely divided gold preparations.
- How light passed through and scattered within the liquid.
- Differences between gold prepared by different experimental methods.
- Changes that occurred when particles aggregated or the preparation was altered.
- The remarkable long term stability of some colloidal preparations.
Details Modern Instruments Revealed
- Individual particle dimensions measured in nanometres.
- Particle shape, morphology and detailed size distributions.
- Electron behaviour at the surface of nanoscale gold.
- Modern optical spectra associated with plasmonic behaviour.
- Direct particle imaging using electron microscopy and related technologies.
WHY IT MATTERED
From Invisible Gold to Modern Nanoscience
Faraday's experiments helped establish a powerful scientific idea: materials can display very different behaviour when divided to extremely small scales. He could not directly image the particles, but he could observe the physical consequences of their presence.
01
Particle Scale
Dividing gold into extremely small particles changes the physical scale at which its surface and surrounding environment interact.
02
Optical Behaviour
The interaction between finely divided gold and light gave Faraday an experimental window into matter that he could not directly see.
03
Colloidal Science
His observations helped establish principles later explored in colloid chemistry, materials science, plasmonics and nanotechnology.
A SCIENTIFIC ARTEFACT
Faraday’s Gold Colloids Are Still Optically Active
One of the most remarkable parts of Faraday’s story is that historic gold preparations associated with his experiments are still preserved in the Royal Institution collection.
Their survival provides a physical connection between nineteenth century experimental chemistry and the modern study of colloids, nanoparticles and optical materials.
Long term colloidal stability is scientifically interesting because suspended particles can gradually aggregate, settle or change their optical behaviour. A preparation that remains visually and optically responsive over very long periods therefore offers an unusual window into the stability of finely divided matter.
Faraday’s surviving preparations form part of the Royal Institution’s scientific collection.
The samples connect present day researchers with experiments carried out in the nineteenth century.
Their interaction with light remains one of the most striking aspects of their scientific legacy.
Their longevity is relevant to colloid science, not evidence of a therapeutic or health effect.
THE LEGACY
From “Divided Gold” to Modern Nanoscience
Faraday was studying nanoscale behaviour more than a century before scientists had the instruments or terminology needed to examine it directly. Later advances in microscopy and materials science would make visible the world that his experiments had only hinted at.
01
1857
Faraday Studies Divided Gold
Faraday publishes his investigations into finely divided gold and its relationship with light, documenting unusual behaviour that differed from ordinary bulk metal.
02
20TH CENTURY
Scientists Begin to See the Nanoscale
Electron microscopy and increasingly sophisticated analytical methods allow researchers to directly examine structures far smaller than those visible with nineteenth century optical instruments.
03
TODAY
Gold Nanoparticles Become a Research Platform
Gold nanoparticles are now investigated across materials science, optics, sensing, electronics and biomedical research, with precise control over size, shape and surface chemistry.
EXPLORE & REFERENCES
Explore the Science Behind Faraday's Gold
Faraday's experiments with finely divided gold are documented in historic scientific literature and preserved within the collections of the Royal Institution.
The Royal Institution
Explore the Royal Institution's collection relating to Michael Faraday's historic gold colloids, including the surviving ruby preparations associated with his experiments.
Explore the CollectionExperimental Relations of Gold and Other Metals to Light
Faraday's Bakerian Lecture presented his investigations into finely divided gold and the remarkable relationship between metallic particles, colour and light.
Royal Society PublishingDiscover More About Colloidal Gold
Continue through the Gold Healing research hub to explore colloidal gold, nanoparticle science and modern production.
SCIENCE GUIDE
What Is Colloidal Gold?
Explore the fundamentals of elemental gold particles, colloidal suspensions and nanoscale behaviour.
→
MODERN PRODUCTION How Colloidal Gold Is MadeMove from Faraday's Victorian experiments to the principles behind modern colloidal gold production.
→
GOLD HEALING 24K Colloidal GoldExplore Gold Healing's modern ruby red 24K colloidal gold formulation.
→
References & Scientific Context
- Royal Institution. Michael Faraday's Gold Colloids. Historical collection documenting Faraday's ruby gold preparations and their preservation.
- Faraday, M. The Bakerian Lecture: Experimental Relations of Gold and Other Metals to Light. Philosophical Transactions of the Royal Society of London, 1857.
- Modern scientific literature concerning gold nanoparticles, colloidal systems, optical properties and localised surface plasmon resonance provides contemporary context for phenomena first investigated experimentally during Faraday's work.
MICHAEL FARADAY FAQ
Questions About Faraday and Colloidal Gold
A concise guide to the key historical and scientific questions surrounding Michael Faraday's work with finely divided gold.
Did Michael Faraday invent colloidal gold?
Not in the modern manufacturing sense. Faraday was one of the earliest scientists to systematically prepare, document and study metallic gold colloids and their interaction with light.
When did Faraday carry out his gold experiments?
Faraday presented his major work on finely divided gold in 1857 in the Bakerian Lecture, later published in the Philosophical Transactions of the Royal Society.
What did Faraday mean by “divided gold”?
Faraday used the term to describe gold broken into extremely small particles rather than existing as a continuous piece of bulk metal. Today, some of the materials he investigated would be discussed in the language of colloids and nanoparticles.
Why were Faraday's gold preparations ruby red?
Finely divided gold can interact with visible light very differently from bulk metallic gold. Modern science explains this through nanoscale optical behaviour involving electrons at the particle surface.
Could Faraday actually see the gold particles?
No. The particles were below the resolving power of the instruments available to him. He instead studied their presence indirectly through colour, light transmission, scattering and changes between different preparations.
What was important about Faraday's 1857 paper?
It provided a detailed experimental investigation of how finely divided metals, particularly gold, interacted with light. The work became an important historical foundation for later colloid and nanoparticle science.
Do Faraday's original gold colloids still exist?
Historic gold preparations associated with Faraday are preserved in the Royal Institution collection, providing a direct physical link to his nineteenth century experiments.
Why is Michael Faraday associated with nanoscience?
Faraday investigated physical behaviour produced by matter divided to an extremely small scale, long before the terminology and instrumentation of modern nanoscience existed. His work therefore occupies an important place in the early history of nanoscale materials research.
Is Faraday's work evidence that colloidal gold has health benefits?
No. Faraday's work concerned the physical and optical behaviour of finely divided gold. Its historical importance does not demonstrate that colloidal gold treats, prevents or cures medical conditions.
