Select content modules
A drop or droplet is a small volume of liquid, bounded completely or almost completely by free surfaces.
Welcome to CWAnswers
CWAnswers is your guide to the sprawling world wide web. The directory aims to provide a useful guide made by users. You can share your knowledge as well - simply sign up and edit your first entry. For questions just contact the team at support - at - cwanswers.com.
Weblinks for Droplets
Top 10 for Droplets
Things about Droplets you find nowhere else.
Wikipedia About Droplets
A drop or droplet is a small volume of liquid, bounded completely or almost completely by free surfaces.
Surface tension
The simplest way to form a drop is to allow liquid to flow slowly from the lower end of a vertical tube of small diameter. When the pendant drop exceeds a certain size it is no longer stable and detaches itself. Drops may also be formed by the condensation of a supercooled vapor or by atomization of a larger mass of liquid. The mass m (or weight mg) of the largest drop that can hang from the end of a tube of radius a can be found from the formula
- \,mg = 2 \pi a \lambda \cos \alpha
-
where λ is the surface tension of the liquid, α is the angle of contact with the tube, and g is the acceleration due to gravity.Fact: date=February 2007 This relationship is the basis of a convenient method of measuring surface tension, commonly used in the petroleum industry.
Droplet
The term droplet is a diminutive form of 'drop' - and typically used for liquid particles of <500µm diameter (although this is for guidance rather than a 'rule'). In spray application, droplets are usually described by their perceived size (i.e., diameter) whereas the dose (or number of infective particles in the case of biopesticides) is a function of their volume. This increases by a cubic function relative to diameter (π.d3/6000 to convert µm into picolitres); thus a 50µm droplet represents a dose in 65 pl and a 500 µm drop represents a dose in 65 nanolitres (65,450 pl).
Optics
Due to the different refractive index of water and air, refraction and reflection occur on the surfaces of raindrops, leading to rainbow formation.
Sound
The major source of sound when a droplet hits a liquid surface is the resonance of excited bubbles trapped underwater. These oscillating bubbles are responsible for most liquid sounds, such as running water or splashes, as they actually consist of many drop-liquid collisions.
Shape
The classic shape associated with a drop (with a pointy end in its upper side) is actually an optical effect due to light reflections and the drops rapid movement. The shape of a drop falling through a gas is actually more or less spherical. Larger drops tend to be flatter on the bottom part due to the pressure of the gas they move through.
Gallery
Image:2006-02-13 Drop-impact.jpg|Impact of a drop of water. Image:2006-01-28 drop-impact backjet.jpg|Backjet from drop impact. Image:Water splashes 001.jpg|A drop of water hitting a metal surface. Image:Post-splash with droplets.jpg|A drop of water hitting a wet metal surface and ejecting more droplets, which become water globules and skim across the surface of the water. Image:Water drop on a leaf.jpg|A drop of water on a leaf. Image:Water droplet backjet.JPG|A triple backjet after impact. Image:Raindrop on a fern frond.jpg|Photo of a raindrop on a fern frond. Image:2006-01-21 Detaching drop.jpg|Detaching drop. Image:Showerheadandwaterdroplets.jpg|Water droplets forming out of a shower head. Image:Asteraceae03.JPG|A drop of water on a Asteraceae
