Science explained

How modern clocks keep time

Clocks count regular physical oscillations, from pendulums and quartz crystals to atomic transitions.

TechnologyMeasurement

Editorial review: August 12, 2026 · Julian E. Marston

A stable oscillator is the heart of a clock

The more predictable the cycles, the more stable the timekeeping.

Quartz uses piezoelectricity

An electric circuit drives and counts mechanical oscillations in a crystal.

Atomic clocks use quantum transitions

The SI second is defined using a specific transition frequency in cesium-133.

Timekeeping supports modern infrastructure

Navigation, telecommunications and scientific measurement depend on precise timing.

Source trail: NIST: SI units
This page explains scientific concepts for general learning. It does not replace laboratory safety procedures, professional engineering guidance, or individualized medical advice.