Priya Nair

A scientific law describes what happens; a theory explains why. The real difference, and why a theory does not become a law with more evidence.

A clinical trial is a carefully designed research study that tests whether a medical treatment is safe and works in people. Here are the phases and how they work.

The Doppler effect is the change in a wave's observed frequency caused by relative motion between source and observer. How it works for sound, light and radar.

Herd immunity is the indirect protection from an infectious disease that occurs when enough of a population is immune. Here is how the concept works.

A half-life is the time it takes for half of a quantity to decay. What it means in radioactivity, how it dates objects, and where else it applies.

A placebo is an inactive treatment with no therapeutic effect of its own, used mainly in research. Here is what it is, the placebo effect, and why trials use it.

Nuclear fusion is the joining of light atomic nuclei into a heavier one, releasing energy. How it powers the Sun and why it is hard to harness on Earth.

A false positive is a test result that says something is present when it is not. How it happens, and how it ties to sensitivity and specificity.

A generic has the same active ingredient as the brand and must prove it behaves the same way in the body. What differs is the packaging, the price and the…

The scientific method is usually taught as a tidy sequence of steps. The logic behind it matters more than the sequence — and real research rarely runs in order.

How do vaccines work? A vaccine shows the body a harmless preview of a pathogen, so it builds antibodies and memory cells before a real infection arrives.

The phrase gets used loosely. Its real meaning is narrower, more careful, and more useful than the marketing version suggests.