Why do we colour a water body blue?why is water blue at some places?

Question

Why do we colour a water body blue?why is water blue at some places?

Answer 1

The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.

However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue. The water then reflects the color of the sky

Answer 2

In the first place, the sky is blue because the molecules in the atmosphere scatrter the blue part of the spectrum, and the red and yellow parts of the spectrum tend to pass straight through.  To us looking from the ground, the blue light seems to be coming from everywhere (this is called 'Rayleigh cattereing'); hence the sky seems blue.

The reason why the sea seems blue is similar; but a little more complicated.  The sea does reflect the blue colour of the sky (or can appear grey in overcast weather), but this only applies to the surface of the sea.  As well as reflecting the blue from the sky, the water molecules scatter the blue light in much the same way as the air molecules in the sky.  This accounts for the 'natural faint blue colour'.

In addition,  the water also absorbs more of the red and yellow wavelengths (which warm the sea), leaving the blue part of the spectrum, as well as part of the green.  This is why deep water can appear bluish-green. (The absorption of the red wavelengths can be noticed by looking at a red object under deep water.  It will appear black; because only blue light is reflected back to us.)

Eventually, at sufficient depth, even the blue light will have been absorbed or scattered away, and deep water will be black and lightless.

This scattering effect is even stronger if there are colloidal materials (very finely divided particles) in the water, such as finely divided clay particles.  These can increase the scattering effect, turning the water an intense blue (which can sometimes be seen in flooded abandoned quarries).  The scattering effect is also greater with ice; which results in the intense blue colour we see if we look down a crevasse in a glacier, or down a hole in the snow made by a ski stock..

For complete, scientific explanations of the scattering effect, look up 'blue sky' in Wikipedia.

Answer 3

Water is faint blue. Although water appears clear in small quanities (like a glass of water), the blue color becomes visible the more water we look through. Thus, deep lakes and seas are bluer than a shallow river.

Other factors can affect the color we see:

   1. Particles and solutes can absorb light, as in tea or coffee. Green algae in rivers and streams often lend a blue-green color. The red sea has occasional blooms of red Trichodesmium erythraeum algae.

   2. Particles in water can scatter light. The Colorado river is often muddy red because of suspended reddish silt in the water. Some mountain lakes and streams with finely gound rock, such as glacial flour, are tourquise. Light scattering by suspended matter is required in order that the blue light produced by water's absorption can return to the surface and be observed. Such scattering can also shift the spectrum of the emerging photons toward the green, a color often seen when water laden with suspended particles is observed.

   3. The surface of seas and lakes often reflect blue skylight, making them appear bluer. [[[ Montana reflection.]]] The relative contribution of reflected skylight and the light scattered back from the depths is strongly dependent on observation angle.

Answer 4

The water has no colour.It is a colourless body.

When you look at the sea or lake or pond from far away distance then you will see the water blue.This is because the sky is blue.Whatever colour the sky produces it is reflected on the earth's surface.When the sky is orange then the water appears to be orange in colour.

During night times the sky is black so the colour of the water is also black.

If one part of the sky has more dark colour then the water present in that part will reflect dark colour.

Answer 5

Water reflects whatever colour the sky is. some minerals liek sulfur and ground quartz and various other minerals in glacial lakes colour them a nice blue. Water however is clear.