1. The problem statement, all variables and given/known data A match of length l=4cm is floating on the surface of the water from a glass. ( the water is at room temperature) If from on one side of the match we pour a few drops of soap, the match starts moving. In which direction is the match mooving and what force is acting upon it? ( sigma (water) = 73 mN/m ; sigma (soap) = 43 mN/m) 2. Relevant equations F= sigma * l 3. The attempt at a solution The force acting on the match is F= (sigma water - sigma soap) * l. I don't fully uderstand how the phenomenon is going on ... could someone draw what's happening in this problem ? thank you!