How the World Wars forged modern time

From the humble wristwatch to the atomic clock, innovations that came out of global conflicts transformed our relationship with time, says Richard Hoptroff

Remembrance Sunday serves as a clear reminder of the devastating impact of war. Yet, amidst the tragedy and loss, these global conflicts brought with them innovation and advancements that continue to shape our lives today. 

Having dedicated my career to researching time, I’m always fascinated to see how the two world wars, in particular, impacted our relationship with time. Their urgency and scale irrevocably altered our need for accuracy, accelerating the development of technologies that influence how we live, work, and even perceive the world around us.

The most visible change you would have seen at the time was the rise of the wristwatch. Prior to World War I, much of the world used pocket watches, but trench warfare demanded practicality. Soldiers needed to know the time without fumbling in their pockets, leading to the widespread adoption of durable, accurate wristwatches. Coordinated attacks, timed artillery barrages and synchronised manoeuvres all depended on accuracy. 

If you were an American soldier in 1914 you would have been fairly surprised to see European soldiers wearing wristwatches on the battlefield. By 1916, a quarter of all soldiers wore wristwatches and in 1917, the British War Department began issuing them to all combatants.

Thus, the humble wristwatch became an indispensable tool. Mass production and standardisation of parts led to lower prices, making wristwatches accessible to a broader audience. And by the 1930s wristwatch production surpassed that of pocket watches, forever changing the landscape of personal timekeeping.

Beyond mere portability, the wars demanded specialised timepieces with enhanced functionalities. Pilots navigating the skies, in what would now be deemed rudimentary aircraft, needed watches with chronographs for precise calculations and luminous dials for visibility in low-light conditions. Naval officers relied on highly accurate marine chronometers to determine longitude and ensure safe navigation across vast oceans, which saw companies like Hamilton play a pivotal role in supporting Allied naval operations. 

On the ground, soldiers required watches that could withstand the rigours of combat, leading to innovations in waterproofing and shock resistance. These wartime advancements laid the foundation for the sophisticated, multi-functional wristwatches we see today.

But perhaps the most profound impact of the World Wars on timekeeping lies in synchronisation. Coordinating large-scale military operations across vast distances necessitated unprecedented levels of temporal precision. 

Coordinating large-scale military operations across vast distances necessitated unprecedented levels of temporal precision

Timing was critical for everything from air raids and naval bombardments to the coordination of infantry movements and communication networks. This led to the development of sophisticated time synchronisation methods, including radio signals and the use of precise quartz clocks. 

Today, the legacy of these innovations are vital in our interconnected world. The end of World War II saw the development of atomic clocks, which work like any normal clock but their pendulums are electrons spinning incredibly fast around atoms. This made them the most accurate timekeeping devices ever invented at the time, losing only about 1 second in 300 billion years. While the first atomic clock was not built until 1949, the groundwork was laid during the war years through advancements in radar and microwave technology.

The development of the atomic clock extends far beyond our everyday lives, underpinning scientific research, telecommunications, and even our understanding of the universe. And it’s crucial to my work now creating accurate time for global infrastructure. 

Atomic clock precision underpins GPS, where each satellite carries an atomic clock, enabling incredibly accurate positioning, which revolutionised navigation, impacting industries from logistics, transportation and emergency response. Additionally, telecommunications rely on atomic clocks for synchronising data transmission across global networks, crucial for cellular networks and internet infrastructure. 

The financial industry too depends on atomic clocks for high-frequency trading and international transactions, demanding accuracy for timestamping and preventing fraud. The development of atomic clocks also enabled Einstein’s theory of general relativity to be tested with unprecedented precision and allowed us to make breakthroughs in particle physics and astronomy, facilitating precise measurements and observations of the universe.

So as we commemorate Remembrance Sunday, let us also remember the ingenuity and resilience that emerged from the two World Wars, reminding us that even in the darkest of times, extraordinary things can happen. The need for accurate, reliable, and synchronised time in the face of conflict drove innovation at an unprecedented pace. From the ubiquitous wristwatch to the atomic clock, these developments transformed our relationship with time, shaping our modern world in the process. 

Richard Hoptroff is the inventor of the first commercial atomic wristwatch and founder of time-synchronisation scale-up, Hoptroff