S U R F A C E T E N S I O N INTRODUCTION

SURFACE TENSION RESULTS FROM THE COHESIVE FORCES BETWEEN LIQUID MOLECULES THE MOLECULES AT THE SURFACE DO NOT HAVE OTHER LIKE MOLECULES ON ALL SIDES OF THEM AND CONSEQUENTLY THEY COHERE MORE STRONGLY TO THOSE DIRECTLY ASSOCIATED WITH THEM ON THE SURFACE. THIS FORMS A SURFACE “FILM” THAT ALLOWS IT TO RESIST AN EXTERNAL FORCE

SURFACE TENSION AT LIQUID-AIR INTERFACES, SURFACE TENSION RESULTS FROM THE GREATER ATTRACTION OF WATER MOLECULES DUE TO COHESION THAN ITS ADHESION (IS THE ATTRACTION BETWEEN TWO DIFFERENT SUBSTANCES) TO AIR.COHESION THE NET EFFECTS IS AN INWARD FORCE AT ITS SURFACE THAT CAUSES WATER TO BEHAVE AS IF ITS SURFACE WERE COVERED WITH A STRETCHED ELASTIC MEMBRANE.

COHESION DEFINITION: IS THE FORCE OF ATTRACTION BETWEEN MOLECULES OF THE SAME SUBSTANCE

SURFACE TENSION AT LIQUID-AIR INTERFACES, SURFACE TENSION RESULTS FROM THE GREATER ATTRACTION OF WATER MOLECULES DUE TO COHESION THAN ITS ADHESION (IS THE ATTRACTION BETWEEN TWO DIFFERENT SUBSTANCES) TO AIR.COHESION THE NET EFFECTS IS AN INWARD FORCE AT ITS SURFACE THAT CAUSES WATER TO BEHAVE AS IF ITS SURFACE WERE COVERED WITH A STRETCHED ELASTIC MEMBRANE.

SURFACE TENSION

BECAUSE OF THE RELATIVELY HIGH ATTRACTION OF WATER MOLECULES FOR EACH OTHER, WATER HAS A HIGH SURFACE TENSION HAS A DIMENSION OF FORCE PER UNIT LENGTH (DYNES PER CM) OR ENERGY PER UNIT AREA ( ERGS PER SQUARE CENTIMETRES)