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
1. What is surface tension ?
2. Surface tension
3. Factors effecting surface tension
4. Phenomena observed due to surface tension
5. Methods of measurement of surface tension
6. 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
1. Capillary rise method
2. Drop analysis methods
3. Drop volume method
4. Relative surface tension measurement using stalagmometer
5. Spinning drop method
6. Maximum bubble pressure method
7. Oscillating jet method
8. Du nouy ring method
9. Du nouy–padday method

8. PRACTICAL APPLICATIONS OF SURFACE TENSION
1. Water striders are insects that can walk on the surface of water because of
surface tension of water
2. 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.
3. 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.
4. 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…