Science in Depth — C1 Essential Words
Ten essential C1 words (Science) with the complete apparatus: pronunciation, simple definitions, natural American examples, collocations, family, the common mistake and spoken usage — plus a 15-question practice quiz. Mark your status on every word.
molecule /ˈmɒlɪkjuːl/ noun C1 Science
Meaning: The smallest unit of a chemical substance that still has its properties, made of two or more atoms joined together.
Example: A water molecule has two hydrogen atoms and one oxygen atom.
Another example: Molecules move faster when heated.
Collocations: water molecule · molecule of · large molecules
Synonyms: particle (wider), compound unit
Word family: molecules (n pl) · molecular (adj)
⚠ Common mistake: Atoms join into molecules; molecules build everything material. Water's famous formula names its molecule: H2O.
🗣 In spoken American English: Chemistry's Lego brick — every substance is built from it.
Register: Formal — science essential.
atom /ˈætəm/ noun C1 Science
Meaning: The smallest unit of a chemical element that can exist; it has a center (nucleus) with electrons moving around it.
Example: Everything is made of atoms.
Another example: An atom of carbon has six protons.
Collocations: an atom of · atom structure · split the atom
Synonyms: particle, nucleus (its center)
Word family: atoms (n pl) · atomic (adj)
⚠ Common mistake: The Greeks named it 'uncuttable' — then science split it and named an age (the Atomic Age) after doing so.
🗣 In spoken American English: Your body holds billions of them older than the Earth itself.
Register: Formal — science core.
cell /sel/ noun C1 Science
Meaning: The smallest basic unit of a living organism; the body is built from trillions of them. Also a small room (prison) and a phone shorthand.
Example: The human body has trillions of cells.
Another example: Plant cells build their own food.
Collocations: body cells · a cell divides · blood cell
Synonyms: unit, building block
Word family: cells (n pl) · cellular (adj)
⚠ Common mistake: Biology's cell builds bodies; the prison's cell holds them; your phone's cell connects them. One short word, three cages of meaning.
🗣 In spoken American English: Every living thing you will ever meet is built from them.
Register: Formal — biology essential.
gene /dʒiːn/ noun C1 Science
Meaning: A part of the DNA in a cell that controls which characteristics living things inherit from their parents.
Example: Eye color is decided by genes.
Another example: Scientists found the gene for the disease.
Collocations: a gene for · gene therapy · genes and traits
Synonyms: DNA unit, heredity factor
Word family: genes (n pl) · genetic (adj) · genetics (n)
⚠ Common mistake: Genes are instructions written in DNA. 'In your genes' also means built into who you are — runners, tempers, talents.
🗣 In spoken American English: Editing them (gene therapy) is medicine's boldest frontier.
Register: Formal — biology essential.
evolution /ˌiːvəˈluːʃən/ noun C1 Science
Meaning: The slow process by which living things change over many generations and new species develop; also gradual development of anything.
Example: Evolution shaped the whale from land animals.
Another example: The evolution of smartphones took decades.
Collocations: theory of evolution · evolution of · human evolution
Synonyms: development, adaptation, natural selection (its engine)
Antonyms: creation (in debates), stagnation
Word family: evolve (v) · evolutionary (adj)
⚠ Common mistake: Darwin's word changed biology forever. Outside science it softens to any slow change — products and ideas evolve too.
🗣 In spoken American English: Finches on islands made it famous; fossils keep proving it.
Register: Formal — science essential.
gravity /ˈɡrævəti/ noun C1 Science
Meaning: The force that pulls objects toward each other, especially the Earth pulling things down; also seriousness.
Example: Gravity keeps our feet on the ground.
Another example: The Moon's gravity moves the oceans.
Collocations: Earth's gravity · gravity pulls · zero gravity
Synonyms: attraction, pull, weight force
Antonyms: weightlessness
Word family: gravitational (adj) · grave (adj — serious, root)
⚠ Common mistake: Newton's apple made it law; astronauts escape it briefly. 'The gravity of the situation' borrows its weight for seriousness.
🗣 In spoken American English: It drops every dropped thing, everywhere, always.
Register: Formal — physics essential.
orbit /ˈɔːrbɪt/ noun / verb C1 Science
Meaning: The curved path an object follows around a planet or star in space; to travel in such a path.
Example: The Earth completes one orbit each year.
Another example: The satellite orbits the planet.
Collocations: in orbit · orbit around · Earth's orbit
Synonyms: path, circuit, revolution
Word family: orbits (n pl) · orbital (adj)
⚠ Common mistake: Planets orbit stars; moons orbit planets; stations orbit Earth. One year = one full orbit of home.
🗣 In spoken American English: Satellites in orbit carry your calls, photos, and weather warnings.
Register: Formal — space essential.
fossil /ˈfɒsəl/ noun C1 Science
Meaning: The remains or shape of a plant or animal from long ago, preserved in rock.
Example: They found a dinosaur fossil in Montana.
Another example: Fossils tell the story of ancient life.
Collocations: dinosaur fossil · fossil record · fossil fuels
Synonyms: remains, imprint, relic
Word family: fossils (n pl) · fossilized (adj)
⚠ Common mistake: Fossil fuels (coal, oil, gas) are named for their origin: ancient life turned to energy. The record fossils leave is life's archive.
🗣 In spoken American English: Montana and the Dakotas are its American treasure houses.
Register: Formal — earth science essential.
specimen /ˈspesəmɪn/ noun C1 Science
Meaning: A single example of something (a plant, animal, rock, or medical sample) collected for study or testing.
Example: The lab examined the water specimen.
Another example: The museum's butterfly specimens are famous.
Collocations: a specimen of · collect specimens · blood specimen
Synonyms: sample, example, exhibit
Word family: specimens (n pl)
⚠ Common mistake: A specimen is a sample WITH a purpose — study, testing, display. Doctors request them; collectors prize them.
🗣 In spoken American English: Museums of natural history are cities of specimens.
Register: Formal — laboratory essential.
particle /ˈpɑːrtɪkəl/ noun C1 Science
Meaning: A very small piece of something; in physics, the tiniest units of matter and energy.
Example: Dust particles float in sunlight.
Another example: Particle physics studies the smallest things.
Collocations: dust particles · particle physics · tiny particle
Synonyms: speck, bit, atom (related)
Word family: particles (n pl) · particular (adj — different word!)
⚠ Common mistake: Careful: particle (tiny piece) vs particular (specific) — cousins with different jobs. Grammar also has particles (small words like 'up' in phrasal verbs).
🗣 In spoken American English: Switzerland's giant collider hunts them under the Alps' border.
Register: Formal — physics essential.
Practice — Science in Depth
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