Analogy is a device commonly used to make something unfamiliar seem familiar by suggesting it is somewhat like something that is already familiar. The idea or phenomenon being introduced or explained is called the target, and the familiar comparison an analogue.
A analogue goes further than simply suggesting one thing is like another (simile) but includes some degree of 'mapping' between the target and analogue.
Read about analogy in science and science teaching
This page presents examples of analogies for science concepts from sources such as the writings of scientists, popular science books and science journalism.
Examples of analogies
For brevity, many examples are paraphrased or edited – the links lead to the full quotation. Most of these examples
- use everyday phenomena as analogues for science concepts, but in some examples
- a science concept is used as the analogue of an everyday phenomenon (⟸),
- or as an analogue for another science or technology concept (⟺).
anatomy
- anatomists analogised from woven goods to body structures ('Psychological Studies of Science and Technology')
animal behaviour
archaeology
- Egyptian embalming techniques were like preserving pears in sugar ('The Royal Society & the Invention of Modern Science')
atoms and molecules
- atoms are like letters of an alphabet (Robert Boyle)
- atoms are like people in seeking out one or several partners ('Explaining Humans: What science can teach us about life, love and relationships')
- covalent and ionic bonds are like different kinds of human relationships ('Explaining Humans: What science can teach us about life, love and relationships')
- diatomic molecule is a discuss thrower that can spin only at certain speeds (Norwood Russell Hanson)
- electrons circling the nucleus as planets might have mountains and oceans ('Patterns of Discovery: An inquiry into the conceptual foundations of science')
- if men were like atoms we could not detect them (J. J. Thomson)
- molecules can be like gloves or socks ('Serendipity. Accidental discoveries in science')
astronomy
- Betelgeuse is ringing at a changed freqency (Dr Andrea Dupree, Harvard & Smithsonian)
- heavens resemble a luxuriant garden (William Herschel)
- life cycles of stars can be inferred like the life cycles of trees (Prof. Martin Rees)
- star after mass ejection is like a washing machine out of balance (Dr Andrea Dupree, Harvard & Smithsonian)
- the Solar System is like a city ('Catching Stardust. Comets, asteroids and the birth of the solar system')
biochemistry
- chemical 'messenger' molecules are the biological equivalent of the postal system ('Vital Principles: The molecular mechanisms of life')
- DNA is like an encyclopedia but metabolites are like a Twitter feed (Ally Morton-Hayward, University of Oxford)
- enzymes are like workstations on a production line ('Vital Principles: The molecular mechanisms of life')
- haemoglobin is like a four-seater car or an unstable four-man boat ('Vital Principles: The molecular mechanisms of life')
- ribosome to mRNA is like a bead on a thread ('Vital Principles: The molecular mechanisms of life')
- structural proteins are molecular scaffolding ('Vital Principles: The molecular mechanisms of life')
biodiversity
- Banca species are as if the Isle of Man had distinct fauna from the rest of the British Isles (Alfred Russel Wallace)
cells
- membrane ion channel is like a turnstile ('Vital Principles: The molecular mechanisms of life')
- relationships are like cell division ⟸ ('Explaining Humans. What science can teach us about life, love and relationships')
chemical bonding and structure
- chemical bonds are like relationships ('Explaining Humans: What science can teach us about life, love and relationships')
chemical substances
- a field called 'host-guest' chemistry ('Serendipity. Accidental discoveries in science')
- benzene has Jekyll and Hyde behaviour (Chemistry World)
- microcomponents of matter collectively give new properties like the assembled parts of a watch (Robert Boyle)
- trace elements are like seasoning added to food (Allison Britt, Geoscience Australia)
chemical reactions
- compound formation is like a marriage ('The Chemical Philosophy of Robert Boyle. Mechanicism, Chymical Atoms, and Emergence')
- conservation of mass in chemical reactions is like not distinguishing Eskimos (Mario Bunge)
- phlogiston was the wrong road (Sir John F. W. Herschel)
- postmodernism is like an acid (Wolfgang Smith – 'Ancient Wisdom and Modern Misconceptions')
- syn addition is like a UFO returning a cow (Dr. Nick Chiappini, University of North Carolina Wilmington)
cosmology
- investigating objects in space is like measuring the timbers of a ship (Henri Poincaré)
- Newton's universe should be an island (Albert Einstein)
development
- human development is like a lightbulb giving rise to a massive office block ('Vital Principles: The molecular mechanisms of life')
Earth and geology
- outermost shell of the Earth is like a massive jigsaw (Catching Stardust: Comets, asteroids and the birth of the solar system)
electricity
energy
- creation of living things is like raising water vapour from the sea into the sky ('Vital Principles: The molecular mechanisms of life')
evolution
- life claws its way up the tree of life (Geoffrey C. Bowker: 'Memory practices in the sciences')
fungi
mycorrhizal fungi is like fibre optic cables (Tony Kirkham, Royal Botanic Gardens, Kew)
genetics and inheritance
- a chromosome is like a string of pearls (Ludwig von Bertalanffy)
- bits of genome are like a coin in the bottom of your pocket ('Science in Action')
- chromosome is like a music tape containing many songs ('Vital Principles: The molecular mechanisms of life')
- genes on a chromosome are like beads on a string ('Some Assembly Required. Decoding four billion years of life, from ancient fossils to DNA')
- hunt for mutation is like searching 65 freight cars for one bad orange (Dr Anne Child, St. George's Hospital, University of London)
- the genetic code is a written text (Wolfgang Smith)
geology
- the underground world is like a house (Athanasius Kircher)
- ores develop from seed like an embryo in the womb (William Gilbert)
gravitation
infectious disease and immune system
- a phthisical soldier is like a glandered horse (Jean-Antoine Villemin)
- allergic responses are like having different PIN codes (Dr Theresa MacPhail, Stevens Institute of Technology)
- antigen to antibody is not like paint to wall (Jules Bordet)
- COVID is like a fire (Prof. Andrew Hayward, UCL)
- infection is more revolution than invasion (Ludwik Fleck)
- plague is like the rain (Dr John Radcliffe)
light
- coloured rays blend like powder paint (Isaac Newton)
- light dragged into the vortices in Bose-Einstein condensate is like a car sucked into a tornado ('Light Years: The extraordinary story of mankind' fascination with light')
- light transmission is like a bird passing through branches (Sir John F. W. Herschel)
mathematical methods
- the geometry of Newton was like the bow of Ulysses (Sir John Frederick William Herschel)
- the invention of differential calculus was like the steam engine (Sir John Frederick William Herschel)
materials
- a solid body is like an artefact (Sir John F. W. Herschel)
- crystals in minerals are like an encrusted statue (Sir John F. W. Herschel)
- exciting ions – like swinging a child – requires the right driving frequency (Alan Holden)
- nylon molecules are like strands in a rope ('Serendipity. Accidental discoveries in science')
- safety glass is like a sandwich ('Serendipity. Accidental discoveries in science')
mechanics
medicine
- lithium is the penicillin of mental health ('Finding Sanity: John Cade, lithium and the taming of bipolar disorder')
microbes
- gut microbes have a cleaning team that work the night shift (Prof. Tim Spector, King's College London)
motion
- impetus is given to the projectile just as heat is given to water by a fire ('Before Galileo. The birth of modern science in Medieval Europe')
nutrition
- mixing of ocean water is like ploughing a field (Professor Angus Atkinson, Plymouth Marine Laboratory)
nature of science and scientific methodology
- a black box resembles a company's annual report (Mario Bunge)
- bifurcationists in the laboratory would be like atheists in the trenches (Wolfgang Smith)
- concept to sense experiences is like ticket number to overcoat (Albert Einstein)
- describing science as a language is like taking cans for canned food (Mario Bunge)
- doing an experiment is like asking a friend to take a risk (Mario Bunge)
- hypothesis-observation is like chicken-egg (Sir Karl Popper)
- hypotheses may be hatched by theories of other species (Mario Bunge)
- physics is like an organism not a machine (Ernst Cassirer)
- pseudo-explanations are like false pearls (Mario Bunge)
- science advances like a column of troops (Ludwik Fleck)
- scientific dialogue is like a game of football (Ludwik Fleck)
- source of scientific problems is its birth (Mario Bunge)
- theories are like true love (Mario Bunge)
- uncoordinated hypotheses are like protoplasm (Mario Bunge)
nuclear processes
- nuclear fission is like cellular fission (Otto Robert Frisch)
- the strong force is like love ('Explaining Humans: What science can teach us about life, love and relationships')
- unstable atom is like a miser (Albert Einstein)
organisms
physics
- quantum formalism is like attempting to breathe in space (Albert Einstein)
- quauntum physics is pianistic where classical physics is violinistic (Norwood Russell Hanson)
physiology
- blood maturation is like wine fermentation (Abū Bakr al-Rāzī)
- nervous system as a telephone switchboard (Ivan Pavlov)
- neurone is like an automatic ballot machine ('Vital Principles: The molecular mechanisms of life')
- reflexes can operate in peaceful republics (Jakob von Uexküll )
plants
- a plant is like an animal turned upside down (Carl Linnæus) ⟺
- fruit-body is the plant's genitals (Carl Linnæus) ⟺
- rostellum partially closes the mouth of the nectary like a trap placed in a run for game (Charles Darwin)
- structure of flower is like instrument used for guiding a thread into the eye of a needle (Charles Darwin)
psychology and mental health
- Rorschach test is like an X-ray picture ('The Inkblots: Hermann Rorschach, his iconic test & the power of seeing') ⟺
waves
- people interfere with each other like waves ('Explaining Humans: What science can teach us about life, love and relationships') ⟸
- the Doppler effect is like swimming away from or towards the shore (Hubert Krivine)
Further examples may be found here:
Further examples of science analogies
The following examples are discussed elsewhere on the site (follow the links):
The nucleus as the brain of the cell (Bert in Y10)
A duster and matchboxes used to explain spectroscopy (a teacher analogy reported by Amy, college student)
Scaffolding learning as akin to enzymatic catalysis (using catalysis as a comparison to explain 'scaffolding' of learning)
Perceiving and remembering are like palaeontology (a text book analogy to explain cognitive processes)
A black hole with a magnetic field is like a shaggy dog (science news item)
A faecal transplant is like wild flower seeds in some soil (an analogy used in a radio science programme/podcast)
Medical screening is like job-shortlisting (an analogy used in a public science talk / podcast)
Viral infection triggering an immune response is like igniting a fire (an analogy used by a scientist interviewed for the radio)
Effect of a plant toxin is like the valves of a car's engine being stuck open (example from a scientist's blog)
NASA's solar probe entering the Sun's corona is like putting your hand in the oven (analogy used by NASA scientist in media interview)
Working memory is a bit like triglyceride structure (an analogy for explaining 'chunking' to science teachers?)
A well-planned curriculum is like an enzyme (an analogy for thinking about curriculum structure)
Animals and plants are like two different types of engine (a historical analogy)
A synchrotron is like a race track (scientist's comparison used in a public talk)
Photosynthesis as an analogy for the COVID-19 pandemic (used by an academic explaining his work on ther social impacts of the pandemic)
The brain's reward pathway is like a teeter-totter (see-saw) (used by an academic and clinician work on addition)
Popping corn is like radioactive decay (a teaching analogy)
Stars are like trees in a forest, in that you can infer life cycles from observing them at one time (Prof. Martin Rees, Astronomer Royal, talking on the radio – compare with the Herschel analogy below)
A molecular chain reaction is like a Newton's cradle (analogy used to report a scientific study)
An atomic nucleus may behave like a liquid droplet that divides into two smaller droplets (Meitner & Frisch propose nuclear fission in the scientific literature)
The structure of buckminsterfullerene is like a football (Kroto and colleagues report the discovery of a new allotrope of the element carbon)
Mea culpa
And as a teacher, it almost becomes instinctive to use them!
Nuclear fusion is like cooking rice in that mass may appear to not be conserved.
Children next to a garden fence as an analogy for the photoelectric effect threshold
Note on analogies, similes and metaphors.
In practice the precise demarcations between similes, metaphors (and anthropomorphisms) and analogies may not be absolutely clear. I have tried to follow the rule that if a comparison is set out to make a structural mapping clear (even if this is not spelt out as a mapping: e.g., an atom with its electrons is like a sun with its planets) this counts as an analogy. Where I do not think a comparison is an analogy, but the comparison is made explicit ("…as if…", "…like…": e.g., the atom, like a tiny solar system) I consider this a simile. When the audience is left to spot a comparison (rather than a literal identity) is being made (e.g., the oxygen atom, this tiny solar system) I class this a metaphor.
Anthropomorphism may be seen as a particular kind of metaphor where a metaphorical feature implies a non-human entity has human attributes (e.g., meteors can be impetuous).
I reserve the right to reassign some of these comparisons in due course!
