Let a drop of detergent or a flake of soap fall between two floating matches placed about a half-inch apart in a bowl of water. The matches will fly apart as though pulled by something. Why?

Friar Tuck

In a soap-and-water solution the hydrophobic (greasy) ends of the soap molecule do not want to be in the liquid at all. Those that find their way to the surface squeeze their way between the surface water molecules, pushing their hydrophobic ends out of the water. This separates the water molecules from each other. Since the surface tension forces become smaller as the distance between water molecules increases, the intervening soap molecules decrease the surface tension. Nov 12 02, 7:40 AM

Son of The Household Cavalry

Did the box you got the soap/detergent from have Tide written on it as that may explain the movement? Nov 12 02, 4:36 PM