Why does the meniscus radius increase when capillary tube length is too short?

  • Context: High School 
  • Thread starter Thread starter Joel Jacon
  • Start date Start date
  • Tags Tags
    Capillary Rise Tube
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
6 replies · 3K views
Joel Jacon
Messages
11
Reaction score
0
What happen when the capillary rise occur in a tube of insufficient length?

My teacher told me that hR = constant where h is height and R is radius of sphere of which the curved surface of meniscus firm a part.
She also told me that if h become less so R has to increase so radius of meniscus has to be large.

I didn't really get what she's meant.

If we take a capillary tube of height h and put it in water then, the tube become filled with water till height h. Now if we break a tube to make it of height less than h then will water flow out?
 
Last edited:
Physics news on Phys.org
This is homework.
Joel Jacon said:
radius of meniscus has to be large.
How large can the radius become? What does that imply?
Joel Jacon said:
will water flow out?
Work out the first question and the answer to this becomes obvious.
 
I told that I didn't understand what the teacher told. Any link on web that explain it would be helpful.
This is not a homework question.
 
I'll ask once more:
Bystander said:
How large can the radius become? What does that imply?
 
I told that's what my teacher said. If I had known the meaning I wouldn't have asked the question.
 
I can tell that someone has not explained this to you very well, or you were not listening!

All you need to know is that the curves of a meniscus are in effect pulling up the water, they are attracted to the glass. In a small tube the pulling area is a large proportion of the surface area and will be able to pull the water high and vice versa.