Investigating streamlining

My class 8 (year 9) students were investigating streamlining today. The
shapes which cyclists and swimmers adopt help them overcome drag.
They then had to design and do an investigation that looked at the effect of shape on speed in our case of a falling object.

The only equipment they had available were:
? long glass tube (measuring cyclinder)
? liquid (oil)
? lump of plasticene
? marker tape
? stop watch
? scales

Great lesson to close off a long day of teaching!