Slow motion with a kitana
The SloMo guys release some awesome videos of fluid dynamics in slow motion. In their latest post, they use a kitana sword to cut through some water bottles in slow motion. In this process, they inadvertently demonstrate principles of inertia, pressure, and gravity. In one of the takes, Dan actually manages to slice evenly through the water bottles. However, one of the tops falls straight down under gravity trapping the water inside.