Does a clock still work in space?

Most clocks work fine in space.

The mechanical manual-wind wristwatches worn by space-walking astronauts work just fine strapped to the outside of the wrist of the spacesuit, in the vacuum of space.

The atomic clock in each GPS satellite works just fine.

While we haven't bothered actually testing, it seems likely that pendulum and water clocks would not work in space, because of the lack of gravity.