Although time may not materially exist, most of us still measure it out using clocks and calendars. From the creation of days to the atomic clock, this episode explores how the abstract concept of time became a countable “reality” — and why metric time worked its way to the heart of Western society.This episode in brief:1. Mapping calendrical time | 03:15The countable time we use in our everyday life is a social construction. This section takes a look at how different cultures divided the abstract concept of time into days, weeks, months and years. We consider the mathematical limitations of basing units on environmental cues like the Earth’s rotation. From the 10-day weeks of ancient China to the alternative names for months in modern Turkmenistan, we explore how our calendars are as much cultural creations, as empirical tools.2. The evolution of clock time | 10:55This section explores the heritage of smaller units for tracking time — like hours, minutes and seconds. We trace the colourful history of time keepers, from water clocks and obelisks to the complex machinery of drive weights, pendulums and vibration. We see how our most precise timepiece — the atomic clock — still falls victim to the inconsistencies of nature; that the quest for a mathematically pure time will always be at odds with the realities of our material universe. 3. The global standardization of time | 18:10Ever wondered where time zones came from? How the US settled on its four standard time belts? Or when the global organization of time began? This section explains all. It lays out the local origins of time standardization, through to the governmentally-sanctioned version of universal clock time we use today. We consider the pressures of local organization, industrialization, expanding transport and communications networks in the drive to create a coordinated social framework for time.4. Living with metric time | 23:40While we may run our lives according to clocks and calendars, that’s not to say we have an easy relationship with them. This section takes a closer look at the social implications of metric time to consider what it means today. Historian Paul Glennie deconstructs the disciplinary narrative of clock time — with its ties to 19th century industrialism — to show why it only represents one part of the social time picture. Using more contemporary examples, we explore what metric time means for our consumer services, personal aspirations and social etiquette.