Who decides how long a second is? - John Kitching
5:16
How fast is the speed of thought? - Seena Mathew
4:51
Why can't you divide by zero? - TED-Ed
6:14
A Brief History Of (Keeping) Time
4:33
How an atomic clock works, and its use in the global positioning system (GPS)
6:16
Einstein's twin paradox explained - Amber Stuver
1:06:23
Why is precision timekeeping so important? - with the National Physical Laboratory
5:31
Por que as máquinas de movimento perpétuo nunca funcionam? - Netta Schramm
5:20