Why Does Water Appear White While Going Over A Waterfall?

The water appears white while going over a waterfall because the water is moving at a high pace and the trapped air in the water creates bubbles. The bubbles are what make the waterfall look white.

If water is really stirred up, or moving at a high pace (a pace that you can expect from waterfalls), then the trapped air in the water creates bubbles. It is these bubbles (tiny air pockets) that make a waterfall look white.

Water is colorless; we all know that, right? Still, the color of snow – which is essentially frozen water – is white. Similarly, water that goes over a waterfall also appears to be white, despite actually being colorless.

Waterfall whitish water

Why is that water white? (Photo Credit : Pxhere)

What’s going on here?

The answer of this lies in how light interacts with matter, along with aeration.


Recommended Video for you:

If you wish to buy/license this video, please write to us at admin@scienceabc.com.

Water and dissolved oxygen

You might already know that water has dissolved oxygen inside of it. It is this dissolved oxygen that helps sustain the lives of aquatic creatures. Normally, you don’t actually see any evidence of oxygen being dissolved in water (apart from the fact that, you know, fish live there). Humans will never understand and appreciate the true value of dissolved oxygen in water bodies (ponds, lakes, rivers etc.) as much as fish do.

Thus, in a still water body, you don’t see the dissolved oxygen, but when water falls over a cliff – like in a waterfall – the dissolved oxygen presents itself, or rather, makes its presence felt.

Aeration

When water is standing still, or moving at a very relaxed, gentle pace, oxygen dissolves in it through diffusion from the surrounding air. However, when water flows rapidly, its flow becomes turbulent. As a result, it offers more surface area for oxygen to diffuse compared to a flat, slow-moving river.

In addition to that, churning waters create turbulence, which causes air to hit the water at a high pressure, allowing more oxygen to dissolve. This sort of aeration creates tons of small bubbles in water, which are eventually responsible for the white color of waterfalls.

How light reflects off water in a waterfall

If you consider a body of water that’s sitting stationary, then you essentially have one surface from which light can reflect (or even refract). Just like a mirror, due to the even surface of a plain mirror, light rays that fall on it are reflected at a constant angle. However, if you roughen up the mirror surface (by denting, scratching or even breaking it), then light rays would still be reflected off it, but in random directions. That’s why crushed glass also looks whitish.

Similarly, in a water body where the water does not show much movement, light reflects at a constant angle. However, when there’s movement in the water, the reflections you see are no longer as clear. Moreover, if the water is really stirred up, or moving at a high pace (a pace that you can expect from waterfalls), then the trapped air in the water creates bubbles. It is these bubbles (tiny air pockets) that make a waterfall look white.

Waterfall whitish water

Tiny air pockets make a waterfall look whitish. (Photo Credit : Pixabay)

These bubbles have their individual surfaces, all of which reflect some part of the light falling on them. This is why you can see reflections of objects on bubbles if you look really closely. As you can imagine, there are a great deal of bubbles in a waterfall, and all of them are of varying sizes. This is why light gets reflected in so many random directions, and what you eventually see is an evenly white color of the waterfall.

This is the same mechanism that makes clouds look white. It’s just a lot of water droplets suspended in the air, all of which scatter light, resulting in the whitish hue of the cloud.

Suggested Reading

Was this article helpful?
YesNo
Help us make this article better
Scientific discovery can be unexpected and full of chance surprises. Take your own here and learn something new and perhaps surprising!

Follow ScienceABC on Social Media:

About the Author

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spearheads the content and editorial wing of ScienceABC and manages its official Youtube channel. He’s a Harry Potter fan and tries, in vain, to use spells and charms (Accio! [insert object name]) in real life to get things done. He totally gets why JRR Tolkien would create, from scratch, a language spoken by elves, and tries to bring the same passion in everything he does. A big admirer of Richard Feynman and Nikola Tesla, he obsesses over how thoroughly science dictates every aspect of life… in this universe, at least.

.
Science ABC YouTube Videos

  1. How Robert J. Oppenheimer became the ‘Father of the Atomic Bomb’How Robert J. Oppenheimer became the ‘Father of the Atomic Bomb’
  2. Higgs Boson (The God Particle) and Higgs Field Explained in Simple WordsHiggs Boson (The God Particle) and Higgs Field Explained in Simple Words
  3. Slowing or Reversing Aging: Can We Live for 180 years?Slowing or Reversing Aging: Can We Live for 180 years?
  4. Detectives Use this Simple Technique to Find Your Fingerprints (Even AFTER You Have Wiped Them Off)!Detectives Use this Simple Technique to Find Your Fingerprints (Even AFTER You Have Wiped Them Off)!
  5. Why is a Circle 360 Degrees, Why Not a Simpler Number, like 100?Why is a Circle 360 Degrees, Why Not a Simpler Number, like 100?
  6. Quantum Mechanics Explained in Ridiculously Simple WordsQuantum Mechanics Explained in Ridiculously Simple Words
  7. Do Fish Get Thirsty and Do They Need to Drink Water?Do Fish Get Thirsty and Do They Need to Drink Water?
  8. Gasoline (Petrol) vs Diesel: Which one is better? A Beginner’s GuideGasoline (Petrol) vs Diesel: Which one is better? A Beginner’s Guide