Humans have been keeping track of time for millennia, to regulate aspects of daily life. In early times they used moving shadows cast by standing stones or sticks in the ground, progressing later to water clocks, hourglasses and pendulum clocks, and eventually to today’s atomic clocks. Prof. Helen Margolis of the UK National Physical Laboratory looks at how we reached the era of atomic timekeeping and what technological advances this has made possible – and what further developments are anticipated in coming years.

You can watch this free event from here, through the YouTube link below, or if you’d like to join questions and discussion, you can also go to the Science Festival’s YouTube channel