English for Science: Essential Vocabulary & Phrases

"hypothesis"

A testable, falsifiable statement predicting a specific outcome or relationship between variables, proposed before an experiment is conducted

"The researchers formulated a hypothesis that increased CO₂ concentration would accelerate the growth rate of the algae under controlled laboratory conditions."

"control group"

A group in an experiment that does not receive the treatment or intervention being tested, used as a baseline to measure the effect of the experimental variable

"The control group received a placebo rather than the active compound, allowing the team to isolate the drug's effect from the placebo response."

"peer review"

The process by which a submitted scientific manuscript is evaluated by independent experts in the relevant field before publication to verify its methods, results, and conclusions

"The study passed rigorous peer review and was accepted by a high-impact journal after two rounds of revision requested by the referees."

"statistical significance"

A result is statistically significant when the probability of obtaining it by chance, assuming the null hypothesis is true, falls below a pre-specified threshold, typically p < 0.05

"The difference in recovery rates between the two treatment arms reached statistical significance at p = 0.02, justifying rejection of the null hypothesis."

"replication"

The independent repetition of an experiment or study by different researchers using the same methods to verify whether the original results can be reproduced

"Concerns about a replication crisis in psychology arose when many landmark findings failed to hold up when subjected to independent replication."

"confounding variable"

An extraneous factor that correlates with both the independent variable and the dependent variable, potentially distorting the apparent relationship between them

"Smoking was identified as a confounding variable in the study of coffee consumption and heart disease, since smokers were more likely to drink coffee heavily."

"meta-analysis"

A statistical technique that combines and analyses the results from multiple independent studies on the same topic to produce a more powerful and reliable overall estimate of an effect

"The meta-analysis pooled data from 42 randomised controlled trials and found a consistent, statistically robust benefit of the intervention across diverse patient populations."

"double-blind trial"

An experimental design in which neither the participants nor the researchers administering the treatment know who is receiving the active intervention and who is receiving the placebo, reducing bias

"A double-blind trial was essential because both patients' self-reported symptoms and clinicians' subjective assessments could be influenced by knowledge of treatment allocation."

"sample size"

The number of observations, participants, or measurements included in a study, which directly affects the statistical power and generalisability of the results

"The reviewers questioned whether the sample size of 34 participants was large enough to detect a meaningful difference with adequate statistical power."

"standard deviation"

A measure of the spread of data values around the mean, indicating how much variability exists in a dataset; a low value means data points cluster closely around the average

"The mean reaction time was 312 ms with a standard deviation of 28 ms, suggesting that most participants responded within a narrow range of values."

"correlation"

A statistical measure of the strength and direction of the linear relationship between two variables, ranging from −1 (perfect negative) to +1 (perfect positive), with 0 indicating no linear relationship

"A strong positive correlation was observed between daily physical activity and cognitive test scores, though the study design could not establish causation."

"outlier"

A data point that lies far outside the range of the other observations in a dataset and may result from measurement error, natural variability, or a genuinely unusual case

"One participant's reaction time was three standard deviations above the group mean and was classified as an outlier before the final analysis was performed."

"regression analysis"

A statistical method for modelling the relationship between a dependent variable and one or more independent variables to make predictions or test hypotheses about causal relationships

"Multiple regression analysis revealed that sleep duration and stress levels together explained 62 percent of the variance in participants' self-reported wellbeing scores."

"raw data"

The original, unprocessed measurements or observations collected during an experiment, before any cleaning, transformation, or statistical analysis has been applied

"The journal required authors to deposit their raw data in an open repository so that other researchers could independently verify the analysis."

"reproducibility"

The ability to obtain the same results when the same data are re-analysed using the same methods, a fundamental requirement for scientific transparency and trust

"Providing detailed analysis scripts and openly sharing raw data are now considered standard practices for ensuring reproducibility in computational research."

"confidence interval"

A range of values, calculated from sample data, within which the true population parameter is expected to lie with a specified level of probability, typically 95%

"The 95% confidence interval for the treatment effect stretched from 1.2 to 4.7 percentage points, suggesting a meaningful but imprecisely estimated benefit."

"abstract"

A concise summary of a research paper, typically 150–300 words, covering the background, objective, methods, main results, and conclusions, allowing readers to quickly assess relevance

"A well-written abstract is critical because many researchers decide whether to read a full paper based on the information contained in those few sentences."

"literature review"

A comprehensive, critical synthesis of existing published research on a specific topic, used to identify gaps in knowledge, establish context, and justify a new study

"The literature review identified that while numerous studies had examined short-term memory in adults, very little work had been done on the same mechanisms in adolescents."

"impact factor"

A numerical measure of the average number of citations received per article published in a journal over the preceding two years, used as a proxy for the journal's influence and prestige

"Nature carries one of the highest impact factors in science, reflecting the intense citation of the high-profile research it selects for publication."

"open access"

A publishing model in which research articles are made freely available online without subscription barriers, either through the journal itself or by self-archiving in an institutional repository

"Funding agencies increasingly require open access publication so that research paid for by public money can be read by anyone without a journal subscription."

"citation"

A reference to a previously published work included in a paper to acknowledge prior research, support a claim, or direct readers to sources of further information

"Every factual claim in the introduction was supported by a citation to a primary research article or authoritative review published in the preceding decade."

"preprint"

A version of a research manuscript posted publicly online before it has undergone formal peer review, allowing rapid dissemination of findings to the scientific community

"The team uploaded a preprint to bioRxiv immediately after submitting to a journal so that colleagues could read and comment on the findings before formal peer review was complete."

"supplementary materials"

Additional data, tables, figures, methods, or code provided alongside a published article but not included in the main text, accessible online for interested readers

"The supplementary materials contained complete model specifications, sensitivity analyses, and extended data tables that supported the conclusions presented in the main paper."

"corresponding author"

The author designated as the primary point of contact for a published paper, responsible for managing correspondence with the journal editors and for post-publication queries

"Readers who wanted access to the original dataset were advised to contact the corresponding author directly using the email address listed in the article."

"gene expression"

The process by which the information encoded in a gene is used to synthesise a functional product, typically a protein, through transcription and translation

"RNA sequencing revealed differential gene expression patterns between tumour cells and healthy tissue, highlighting several candidate targets for therapeutic intervention."

"natural selection"

The evolutionary mechanism by which heritable traits that increase an organism's reproductive success become more common in a population over successive generations

"The rapid evolution of antibiotic resistance in bacteria is a clear contemporary example of natural selection operating over a very short timescale."

"cell membrane"

The selectively permeable phospholipid bilayer that surrounds every living cell, controlling the movement of substances in and out and mediating communication with the external environment

"Fluorescence microscopy showed that the drug molecule was unable to cross the cell membrane and therefore could not reach its intracellular target."

"ecosystem"

A biological community of interacting organisms together with their physical environment, functioning as a system through flows of energy and cycling of nutrients

"The introduction of wolves to Yellowstone transformed the ecosystem by reducing overgrazing, which allowed riverbanks to revegetate and altered the course of streams."

"mutation"

A permanent change in the DNA sequence of an organism, which may be harmful, neutral, or occasionally beneficial, and which can be passed to offspring if it occurs in germline cells

"The researchers identified a point mutation in the BRCA1 gene that substantially elevated the carriers' lifetime risk of developing breast and ovarian cancer."

"biodiversity"

The variety of life on Earth at all levels, from genetic variation within species to the richness of species within ecosystems and the diversity of ecosystems across landscapes

"Habitat destruction remains the single greatest threat to biodiversity, having driven many species toward extinction at a rate far exceeding the natural background level."

"enzyme"

A biological catalyst — almost always a protein — that dramatically accelerates the rate of a specific chemical reaction within a living cell without being consumed in the process

"The enzyme catalase converts hydrogen peroxide to water and oxygen so rapidly that a single molecule can process millions of substrate molecules per second."

"homeostasis"

The ability of a living organism or system to maintain stable internal conditions within a narrow range despite changes in the external environment

"The kidneys play a central role in homeostasis by regulating blood pH, fluid volume, and electrolyte concentrations within the tight tolerances required for cell survival."

"thermodynamics"

The branch of physics that deals with heat, work, temperature, and the transformation of energy, governed by four fundamental laws that constrain all physical and chemical processes

"The second law of thermodynamics states that the total entropy of an isolated system can only increase over time, explaining why many natural processes are irreversible."

"catalyst"

A substance that increases the rate of a chemical reaction without being consumed, by providing an alternative reaction pathway with a lower activation energy

"Industrial ammonia synthesis relies on an iron catalyst to make the reaction proceed at economically viable rates at temperatures that are achievable at scale."

"electromagnetic spectrum"

The complete range of electromagnetic radiation, ordered by frequency and wavelength, from very-long-wavelength radio waves through microwaves, infrared, visible light, ultraviolet, X-rays, to gamma rays

"Medical imaging exploits multiple regions of the electromagnetic spectrum: X-rays for bone structure, infrared for surface temperature, and radio-frequency waves for MRI scans."

"quantum mechanics"

The branch of physics that describes the behaviour of matter and energy at atomic and subatomic scales, where energy is quantised and particles exhibit both wave-like and particle-like properties

"Quantum mechanics is fundamental to understanding chemical bonding, transistor behaviour, laser operation, and the spectroscopic properties of atoms and molecules."

"equilibrium"

The state of a system in which opposing forces, processes, or influences are balanced, so that there is no net change in the system's macroscopic properties over time

"Le Chatelier's principle predicts how a chemical system at equilibrium will shift in response to a change in concentration, pressure, or temperature."

"isotope"

One of two or more atoms of the same element that have the same number of protons but different numbers of neutrons in their nuclei, giving them different atomic masses

"Radiocarbon dating uses the known decay rate of the carbon-14 isotope to estimate the age of organic materials up to about 50,000 years old."

"viscosity"

A fluid's resistance to flow, arising from internal friction between adjacent layers moving at different velocities; a high-viscosity fluid flows slowly compared to a low-viscosity one

"The viscosity of blood increases significantly at low temperatures, which has important implications for cardiovascular physiology in cold-climate species."

"oxidation state"

A number assigned to an atom in a molecule or ion that represents the degree of electron loss or gain, used to track electron transfer in redox reactions

"Manganese can adopt oxidation states ranging from −3 to +7, which gives it unique catalytic versatility in both industrial and biological settings."

"carbon cycle"

The biogeochemical cycle through which carbon atoms continuously move between the atmosphere, oceans, soils, living organisms, and rocks, regulating atmospheric CO₂ concentrations on timescales from days to millions of years

"Human combustion of fossil fuels has disturbed the carbon cycle by releasing carbon stored over millions of years back into the atmosphere within decades."

"greenhouse effect"

The warming of Earth's surface caused by greenhouse gases — including water vapour, CO₂, and methane — absorbing and re-emitting infrared radiation that would otherwise escape to space

"Without any greenhouse effect, Earth's average surface temperature would be approximately −18°C rather than the +15°C that makes the planet habitable."

"tectonic plates"

The large, rigid segments of Earth's lithosphere that move relative to one another, driven by convection in the underlying mantle, generating earthquakes, volcanoes, and mountain ranges at their boundaries

"The Himalayas were formed by the ongoing collision between the Indian and Eurasian tectonic plates, a process that began roughly 50 million years ago."

"ocean acidification"

The ongoing decrease in the pH of Earth's oceans caused by their absorption of excess atmospheric CO₂, which forms carbonic acid and reduces the availability of carbonate ions essential for shell-building marine organisms

"Ocean acidification has already reduced the calcification rates of many reef-building corals, threatening the biodiversity of tropical marine ecosystems."

"climate feedback"

A process in which an initial change in climate causes a secondary effect that in turn amplifies (positive feedback) or dampens (negative feedback) the original change

"Arctic sea-ice loss is a positive climate feedback: as ice melts, the darker ocean absorbs more solar radiation, causing further warming and further ice loss."

"stratigraphy"

The branch of geology that studies the order, position, and characteristics of rock and sediment layers to reconstruct the history of environments and life on Earth through geological time

"High-resolution stratigraphy of the lake sediment core revealed annual laminations that allowed the researchers to reconstruct drought cycles over the past 12,000 years."

"albedo"

The fraction of incoming solar radiation that a surface reflects back into space, expressed as a value between 0 (completely absorbing) and 1 (perfectly reflective)

"Fresh snow has a high albedo of around 0.9, while open ocean has a low albedo of around 0.06, making the ocean a much more effective absorber of solar energy."

"proxy data"

Indirect evidence of past climate conditions preserved in natural archives such as ice cores, tree rings, coral skeletons, and lake sediments, used to reconstruct climate before instrumental records began

"Oxygen isotope ratios in Antarctic ice cores serve as proxy data for past air temperatures, extending the climate record back 800,000 years."