In this paper we report an investigative activity on hydrodynamics, in the context of an
inquiry-based learning project. The aim is to analyse the experiment of a bullet shot underwater.
Using Tracker , a video analysing and modelling software, the displacement of the bullet was
measured as function of time, processing a slow motion video from YouTube. It was found that the
displacement of the bullet is well described in the first 20 ms by the inviscid flow regime, where
the Newtonian drag force overcomes the viscous drag. This behaviour is discussed in the context of
what Richard Feynman’s famous Lectures on Physics describes as ‘The Flow of Dry Water’ .