BBC2 年
The 12 and 24 hour clock
A clock with hands (an analogue clock) shows us the numbers 1-12. There are 24 hours in one day, so we measure time by splitting the day into two halves. The first 12 hours of the day, from ...
BBC2 年
The 12 and 24 hour clock
A clock with hands (an analogue clock) shows us the numbers 1-12. There are 24 hours in one day, so we measure time by splitting the day into two halves. The first 12 hours of the day, from ...
BBC15 天
How to read the Doomsday Clock
The Doomsday Clock depicts how close humanity is to armageddon – but where did it come from, how do you read its time, and what can we learn from it? Existential risk researcher SJ Beard explains.