Why is Water Colourless?

Why is water colourless?

Milk is white. Lemonade is cloudy. Orange juice is orange. Pretty much everything you drink or eat has some color. Then why is that you can see through a glass full of water? Why is water colorless Have you ever wondered?

Here is why. You must already know that white light is made up of several colors. Now anything solid or liquid is made up of tiny particles. Now when light falls on these particles, they absorb some colors from the light and while some other color doesn’t  get absorbed. This color gets reflected back from the particles and is the one that reaches our eyes. The thing therefore appears to be of the color that is reflected back and reaches our eyes. For example when you look at orange juice, all colors from the light are absorbed except orange color. Orange color is reflected back and reaches our eyes and therefore the juice looks orange.

Water is colorless and transparent because ALL except a tiny bit of blue (for pure water) are reflected back. Since water reflects all colors together it looks colorless.

Credit: Thanks to Dave Nelson and Claude we updated this post with what is scientifically correct. We apologize for the error in our post.


  1. Water is colourless because it does not absorb much of any light we can see.

    Kids, you can check this by yourselves: put something of colour behind a glass of water. You will see its colour perfectly, just the same as when light goes through air.

  2. I have a question. When water reflects all colors of light, it appears colourless. What about white substance? When all colours of light travel together, they appear white. Then does that mean white substance reflect all colours of light? What causes the difference between being colourless and white?

    • Water lets light to pass through it. Hence, it appears ‘transparent’ and colourless. Whereas, an ‘opaque’ white object will reflect all the frequencies of light together. Hence, the object appears white (and not colourless like water).

  3. I’ll make it more clear.The water in sea contains some amount of salts such as copper sulfate which absorb all the red yellow and orange shades leaving behind slight green and more of blue color that is reflected by the sea.Thus water in sea looks blue. Coming to glass water, it usually contains pure consumable water which does not have the salts that sea water has and hence it does not absorb any color in particular and reflect all the colors together in equal proportion,making it look colorless. It is as simple as that!

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