Skip to main content

Surface Tension

Surface tension

It is the force of attraction(cohension) between the similar surface particles of fluid which forms films .

Reasons : various forces such as vanderwaal forces , hydrogen bonding forms web of water molecules on the surface.

Concept :
At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to cohesion) than to the molecules in the air (due to adhesion). The net effect is an inward force at its surface that causes the liquid to behave as if its surface were covered with a stretched elastic membrane. 

Eg. A. Ants and other spinder walk through surface of water.
   
   B. Rain drop has a  shape

Additional Information :
Its dimension is same as that of force per unit length

Water has surface tension of 72.8 milli newtons at 20 degree centigrade

Labels:

Comments

Post a Comment

Popular posts from this blog

Difference between Attemperator and De-superheater

Attemperator are fitted in order to keep the steam temperature in the final stages of the superheater within certain desired limits . This is done for two main reasons . 1. The most important is the protection of the superheater tube material from the effects of overheating. *Mild steel superheater tubes tubes should not be subjected to steam temperatures in excess of 455℃. 2. The formation of bonded deposits on superheater tubes can be reduced if steam and gas streams within certain temperature ranges are prevented from coming into contact of each other. De-Superheater is used to reduce the temperature of a quantity of superheated steam and make it suitable for used in auxiliary services requires low temperature or saturated steam . *The reason for doing this way rather than by taking the saturated steam direct from steam drum , is to protect the superheater , these must be protected against overheating under all conditions of load by circulating steam through them . *Al...
Post a Comment
Read more

REGULATION FOR THE DISCHARGE OF SEWAGE ONBOARD SHIP

Regulation for the Discharge of Sewage  According to Marpol (73/78) annex  IV   , prevention of pollution from sewage it has 11 regulation according to Marpol consolidation 2002. Regulation 1 deals with basic definition of new ship, existing ship , sewage , nearest land etc. Regulation 2 deals with application of this convention on different types of ship based on their tonnage and number of crew capacity. Regulation 3 deals with various types of surveys which is conducted initially from the ship construction to operational level. Regulation 4 deals with the  issuing of ISPP (International Sewage Pollution Prevention ) certificate. Regulation 5 deals with issuing of certificate by another government i.e, there is no issue of ISPP certificate to flag which is not the party of organisation . Regulation 6 deals with the forms of certificate i.e ISPP certificate shall be drawn in official language of issuing country if the issuing country official langua...
2 comments
Read more