Units and SI prefixes

Understand the units behind the numbers: what each unit measures, how it is defined, and where it is useful.

Metre (m)lengthKilogram (kg)massSecond (s)timeKelvin (K)thermodynamic temperatureNewton (N)forcePascal (Pa)pressureJoule (J)energyWatt (W)powerHertz (Hz)frequencyLitre (L)volumeSI prefixes10⁻³⁰ → 10³⁰

The periodic table, built for exploration

118 elements. One clear map of matter. Explore the periodic table, open any element, or jump straight into scientific converters.

Dmitri Mendeleev arranged the known elements so that recurring chemical properties became visible. He deliberately left gaps where the pattern suggested undiscovered elements should exist. That idea — structure before completeness — still makes the periodic table one of science’s most powerful maps.

Phenomena

Everyday scientific phenomena explained with living diagrams and concise, carefully checked text. The motion helps show the mechanism; the article explains what the diagram simplifies.

Evaporation is the passage of molecules from the surface of a liquid into the gas phase. Water does not need to boil for this to happen.