Measuring surface tension / bouncing water droplets

AI Thread Summary
To measure surface tension experimentally, methods such as the drop weight method or the capillary rise method can be used. When high-velocity water droplets strike a water surface at a small angle, they can bounce off instead of merging due to the effects of surface tension and molecular polarity. The droplets may retain their shape momentarily because the negative charges of the oxygen atoms in the water molecules repel each other, preventing immediate merging. Additionally, an air pocket may form between the droplet and the water surface, contributing to the bouncing effect. Understanding these interactions requires a deeper exploration of molecular behavior and surface tension dynamics.
echoSwe
Messages
38
Reaction score
0
Hello!

Question one: How do u measure the surface tension? (I'm looking for the experimental method now, not the theoretical one by itself)

Question two: When ejecting water droplets at a high velocity at a small angle to a water surface/body, the droplets might not merge with the body of water, but rather bounce off it and lay a couple of seconds as droplets before merging with the body of water.

Why?

It has got to do something with surface tension and the polarity of the molecules being directed outwards I think. The surface tension in the manner that the droplets bounce off due to the speed they hit the surface at, and polarity because they don't merge. But how exactly does this work? I'm thinking that the H-O-H turns its negative side (the O) inwards in the droplets, and the surface of the water body behaving in the same way, turning the outer molecules inwards (the O towards the body itself). The charges + and + hence appell each other and the droplet may be able to float a while.

The question is how this works _really_? I've heard something about charged tops or something, or is it that an airpocket is created between the droplet and the body? Please help me =)

Cheers
Henke
 
Physics news on Phys.org
Anyone?
 
I really need help??!
 
Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top