  Spreading of different types of fluid on substrates under an impressed force
is an interesting problem. Here we study spreading of four fluids, having
different hydrophilicity and viscosity on two substrates - glass and perspex,
under an external force. The area of contact of fluid and solid is
video-photographed and its increase with time is measured. The results for
different external forces can be scaled onto a common curve. We try to explain
the nature of this curve on the basis of existing theoretical treatment where
either the no-slip condition is used or slip between fluid and substrate is
introduced. We find that of the eight cases under study, in five cases
quantitative agreement is obtained using a slip coefficient.
