# Measuring surface tension / bouncing water droplets

• echoSwe
In summary, the conversation discusses the experimental method for measuring surface tension and the phenomenon of water droplets bouncing off a water surface instead of merging. The reason for this lies in the surface tension and polarity of the molecules, which causes the droplets to repel each other and remain suspended for a short period of time. The exact mechanism behind this is unclear and further research is needed.
echoSwe
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

Anyone?

I really need help??!

## 1. What is surface tension?

Surface tension is a property of liquids that causes the surface of the liquid to act like a thin, elastic membrane. It is caused by the cohesive forces between the molecules of the liquid.

## 2. How is surface tension measured?

Surface tension can be measured using a variety of methods, including the drop weight method, the capillary rise method, and the Du Nouy ring method. These methods involve measuring the force required to break the surface tension of a liquid.

## 3. What factors affect surface tension?

Surface tension is affected by the type of liquid, temperature, and the presence of solutes. Liquids with stronger intermolecular forces tend to have higher surface tension, while increasing temperature and adding solutes can decrease surface tension.

## 4. Why do water droplets bounce on a hydrophobic surface?

Water droplets can bounce on a hydrophobic surface because the surface tension of the water causes it to form a spherical shape, which minimizes its surface area. When the droplet hits the surface, the surface tension allows it to resist being flattened, causing it to bounce.

## 5. How is surface tension related to the bouncing of water droplets?

The surface tension of water is what allows droplets to form and maintain their spherical shape. When a droplet hits a surface, the surface tension allows it to resist being flattened, causing it to bounce. The surface tension also helps to keep the droplet intact as it bounces, preventing it from breaking apart.

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