Science 14
From cells to volcanoes, from photosynthesis to cocoa butter: natural phenomena explained with verified sources, a map to find your way and a quiz to make it stick.
- Fermentation: What It Is and How It Transforms Food Fermentation is the process by which yeasts, bacteria and even our own muscle cells extract energy from sugars without using oxygen. It yields little, 2 molecules of ATP per glucose against roughly 38 from respiration, but it works wherever oxygen cannot reach. Its waste products, such as alcohol and lactic acid, give food its flavour and protect it from harmful microbes: that is how wine, beer, bread, yogurt and vinegar are born. It was Louis Pasteur who proved, from 1857 onwards, that living microorganisms are behind fermentation.
- Gluten: what it really is and how it works Gluten is not a mysterious additive: it is the set of storage proteins in wheat grain, two families called gliadins and glutenins, which form an elastic net when flour meets water and trap the gases of fermentation. That net is what makes bread rise and pizza dough stretch. In roughly one person in a hundred, though, fragments of these proteins trigger celiac disease, a permanent autoimmune inflammation of the gut. For everyone else, the available research does not show that gluten is harmful in itself, nor that gluten-free products are automatically healthier.
- The Greenhouse Effect: What It Is and How It Works The greenhouse effect is the natural mechanism by which certain gases in the atmosphere, such as carbon dioxide and water vapor, trap part of the heat that Earth sends back toward space. It works like a blanket: without it, the planet's average temperature would be about -18°C instead of the current 15°C. Since the mid-1700s, though, burning coal, oil and gas has raised atmospheric CO₂ by 50%, and the blanket has grown thicker. The result is global warming: 2024 was the warmest year on record.
- Leavening: what it is and how it works Leavening is the process that inflates a dough from the inside: a gas (almost always carbon dioxide) forms bubbles that get trapped in the stretchy mesh of gluten. The gas can come from living microorganisms that ferment sugars (baker's yeast, sourdough), from a chemical reaction between baking soda and an acid (baking powder), or simply from steam and air expanding in the oven. During baking the bubbles grow one last time, then the structure sets: that is how bread gets its crumb and cakes get their softness.
- Volcanoes and Earthquakes: Why the Earth Shakes Volcanoes and earthquakes are two faces of the same phenomenon: the Earth's internal heat moves the tectonic plates, and along their boundaries energy builds up and breaks loose. When rock snaps along a fault, the ground shakes; when magma finds a path to the surface, a volcano erupts. Nobody can predict an earthquake, but scientists can estimate probabilities, engineers can build stronger, and volcanoes can be watched around the clock. Italy lives with both: thousands of small tremors every year, Vesuvius quiet since 1944, and the Campi Flegrei caldera under constant observation.
- The Water Cycle: What It Is and How It Works, Stage by Stage The water cycle is water's never-ending journey between the oceans, the atmosphere and the land. The sun's heat makes it evaporate, the vapor condenses into clouds high up, then water falls back as rain or snow and returns to the sea through rivers and groundwater. Along the way it changes state again and again, but it is never created or destroyed. That is why the cycle has no starting point and no end.
- Why does chocolate melt in your mouth? The science of cocoa butter Chocolate melts in your mouth thanks to cocoa butter, the fat that makes up about 30% of a bar and melts at around 34 °C, just below body temperature. Its molecules can stack into six different crystal forms, each with its own melting point, and only form V delivers the gloss, the crisp snap and the perfect melt on the tongue. Chocolatiers get it through tempering, a controlled temperature cycle that steers crystallization. When the structure rearranges on its own, the whitish film of fat bloom appears on the surface.
- Arginine: what it is and how it affects nitric oxide, blood pressure, and exercise Arginine is an amino acid the body partly makes on its own and also gets from food, mainly grains, meat and dairy; it's the precursor of nitric oxide, the molecule that relaxes blood vessels. Independent meta-analyses find modest but measurable effects on blood pressure, athletic performance, mild-to-moderate erectile dysfunction and wound healing, often at doses well above what a normal diet provides. The European food safety regulator, EFSA, has nonetheless rejected all the major health claims proposed for arginine, citing the absence of a recognised cause-and-effect relationship at the required standard. There's also a serious, well-documented contraindication: in a clinical trial of patients with a recent heart attack, arginine was linked to significantly higher mortality, serious enough that the trial was stopped early.
- Creatine: what it is, how it works, and what the research really shows Creatine is a natural compound the body makes and stores mainly in muscle, where it helps regenerate energy during short, intense effort. Taken as a supplement, usually as creatine monohydrate, it raises muscle stores and in studies improves performance in repeated high-intensity exercise by 10-20%. The available research finds no signal of kidney harm at standard doses in healthy people, while the possible cognitive benefit remains genuinely contested. Roughly a fifth to a third of people respond poorly to a classic loading protocol.
- The cell: what it's made of and how it works The cell is the smallest unit capable of living: every living thing is made of cells, from just one (bacteria) to tens of trillions (us). It works like a tiny factory: the membrane controls what comes in and out, the nucleus stores the instructions (DNA), the mitochondria produce energy, and the other organelles build, package and recycle the molecules of life.
- DNA: what it is, how it's built and what it does DNA is life's instruction manual: a very long molecule shaped like a double helix, written in an alphabet of just four "letters" (A, T, C, G). Stored in the nucleus of every cell, it holds the recipes — the genes — for building all the organism's proteins. Every time a cell divides, the DNA is copied and passed on: that's how traits travel from one generation to the next.
- Mitosis vs Meiosis: All the Differences Mitosis and meiosis are the two ways cells divide. Mitosis produces two cells identical to the parent: it's for growing, repairing tissues and replacing old cells. Meiosis produces four cells with half the chromosomes, each one different: it creates the gametes (eggs and sperm) for reproduction. In short: mitosis copies, meiosis shuffles and halves.
- Muscle hypertrophy: how muscle grows and what the research says Muscle hypertrophy is the enlargement of the fibres you already have, not the appearance of new ones. It happens when resistance training puts muscles under more tension than they are used to: the tissue responds by building more contractile protein than it breaks down, and repeating that cycle for months thickens the fibre. The most recent research syntheses link hypertrophy above all to the total amount of work done each week, while load is free to vary across a wide range.
- Photosynthesis: What It Is and How It Works Photosynthesis is the process by which plants turn sunlight, water and carbon dioxide into glucose (their food) and oxygen. It happens in the leaves thanks to chlorophyll, the green pigment that captures the energy of light. It is the process that feeds almost all life on Earth and produces the oxygen we breathe.