surface tension

What is surface tension ?
Surface tension
Factors effecting surface tension
Phenomena observed due to surface tension
Methods of measurement of surface tension
Practical applications of surface tension

1. CIA 4 PRESENTATION ON SURFACE TENSION VAIBHAV SANJAY PATIL DIV : - SEME-A ROLL NO. : - 04 GUIDED BY : - PROF. D. R. SATPUTE

2. CONTENTS What is surface tension ? Surface tension Factors effecting surface tension Phenomena observed due to surface tension Methods of measurement of surface tension Practical applications of surface tension

3. WHAT IS SURFACE TENSION ? Surface tension is defined as the force acting over the surface of liquid per unit length of the surface perpendicular to the force. It is due to the phenomena of surface tension that the drops of water tend to assume a spherical shape to attain minimum surface area. SI unit is N/m

4. SURFACE TENSION Molecules in the bulk liquid are surrounded in all directions by other molecules for which they have an equal attraction (only cohesive forces). Molecules at the surface can only develop cohesive forces with other molecules that are below and adjacent to them, and can develop adhesive forces with molecules of the other

5. FACTORS EFFECTING SURFACE TENSION 1. Temperature 2. Solute concentration 3. Intermolecular forces 4. Hydrogen bonding

6. PHENOMENA OBSERVED DUE TO SURFACE TENSION 1. Excess pressure in a soap bubble. 2. Formation of spherical droplets. 3. Capillarity. 4. Wetting and non-wetting properties of certain liquids

7. METHODS OF MEASUREMENT OF SURFACE TENSION Capillary rise method Drop analysis methods Drop volume method Relative surface tension measurement using stalagmometer Spinning drop method Maximum bubble pressure method Oscillating jet method Du nouy ring method Du nouy – padday method

8. PRACTICAL APPLICATIONS OF SURFACE TENSION Water striders are insects that can walk on the surface of water because of surface tension of water Mosquito eggs can float on water because of its surface tension. Kerosene is sprayed on water so that the mosquito eggs sink and the breeding stops. Warm water is used for washing purpose as heating increases the surface area and reduces surface tension. This action is replicated by adding detergents to cold water. A needle placed on water can be made to float due to the surface tension of water. If the surface is ruffled, the needle will quickly sink.

9. CONCLUSION From this presentation we can get the information about surface tension it’s phenomena, methods of measurement and practical applications of surface tension

10. REFRENCE Dr. Arindam chatterjee “ INTERFACIAL PHENOMENA ” jaipur national university Fluid mechanicas by R.K. Bansal  Introduction to fluid mechanics and fluid machines by S.K. Som , gautam biswas publisher : mcgraw hills edition

11. THANK YOU…