(b) State two methods by which the surface tension of a liquid can be reduced.
(a) Surface tension
Surface tension is the property of the free surface of a liquid by which it behaves like a stretched elastic membrane, tending to contract to the smallest possible area. It is measured as the force acting at right angles per unit length along a line drawn in the surface: \[ \gamma = \frac{F}{L} \] with S.I. unit newton per metre (N m-1). It arises from the net inward cohesive pull on molecules at the surface.
(b) Two methods of reducing surface tension
Adding a detergent, soap or other surface-active impurity to the liquid.
Surface tension is the property of the free surface of a liquid by which it behaves like a stretched elastic membrane, tending to contract to the smallest possible area. It is measured as the force acting at right angles per unit length along a line drawn in the surface: \[ \gamma = \frac{F}{L} \] with S.I. unit newton per metre (N m-1). It arises from the net inward cohesive pull on molecules at the surface.
(b) Two methods of reducing surface tension
Adding a detergent, soap or other surface-active impurity to the liquid.