Water
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When is water white?

3 Modules 12 Articles Easy

About this course

Liquid water splash - White water

Splash made by a swimmer

Turbulent water and air

 Liquid water is white at the interfaces of water and air when there is turbulence.

Wave crests, breaking waves, waterfalls, the wake of ships and boats, river whitewater, water splashes, and water jets are all examples of turbulent water/air interfaces. 

What happens at turbulent water/air interface s ?

Agitated water at the air interface encourages aeration of liquid water with air bubbles.

Ginger ale bubbles

Ginger ale bubbles

What about bubbles from soda?

It does not have to be air molecules. Any gas that does not absorb light has the capacity to create bubbles that are white. 

Shaking a can of soda will create a mass of white CO2 bubbles. 

Here's what happens with agitation of water and air:

 

  • Water dissolves some of the air 

  • The churning water creates air bubbles and air pockets 

  • The turbulent water generates water droplets that are  held in place within air pockets.

In other words, churning water  creates environments where air bubbles and water mix together.

The gasses within air (Nitrogen, oxygen, carbon dioxide) do not absorb light.

Light gets refracted (bounced around) in the different interfaces between liquid and gas.

It is the disorganization of those interfaces - a mass of bubbles - that prevents light from making its way through. 

Since none of the light is absorbed and some of it is reflected back to us; we see the mass of bubbles as white. 

Conclusion

A disorganized mass of air bubbles held in place by water will reflect light. 

This is the whiteness you see in wave crests and splashes.

Picture credits:

  1. Hijab J. Breaking waves, Cape Cod. December, 2019.
  2. Horia Varlan . Splash made by a swimmer jumping into the sea. Flicker - photo sharing. Taken on Aug 5, 2009.
  3. F Delventhal . Ginger Ale. Flickr photo-sharing. Taken on April 30, 2010. 
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Course Structure

4 Lessons

Module 1: Liquid and frozen water

 

This module is about water, both in liquid and frozen state. 

 

The feature image shows the whiteness of water when it is ice, bubbling down a waterfall, and snow. 

 

Feature image:

Frozen ice, snow and waterfall on the Ottauquechee River.

Taken from the Queeche covered bridge, Jan 2020.

Waves and bubbles

Liquid water is white when there is turbulence. 

 

Foam

Uneven air masses create white color

Snow

Water is also white when air bubbles are mixed in with frozen water molecules.

White ice, hail, and blue ice

Frozen ice cubes can look as if they have clouds in them.

3 Lessons

Module 2: What about fog?

Fog with its ghostly cold fingers. 


If fog is made of water droplets. How is it so murky?

 

Because the defining characteristic for fog is not liquid water, but water vapor.

 

Feature image:

tracyshaun. blanket of fog pouring over the headlands.

Flickr photo-sharing. Taken Oct 29, 2008.

Fog development is simple

Take warm water vapor molecules and cool them down. 

Fogged up mirrors

If fog were filled with minute water droplets, and water is clear, why is fog so murky?

What about the water droplets in fog?

Here's where the liquid droplets in fog come in.

5 Lessons

Module 3: What about clouds?

Clouds are my favorite structure.

 

They are so diverse.

 

And, yet, there is a common meaning to them that links them together. 

 

Feature image:

Chris Harrison. Clouds. Flickr.

Taken on June 15, 2010. 

The difference between fog and clouds

Fog and clouds develop in different ways.

The darkest layer

Nimbus clouds have dark layers on their underside. 

 

The more the air, the whiter the cloud

Why are clouds brilliantly white?

Different cloud shapes

Cloud shapes are as variable as the air, the wind, and the water vapor molecules that mix and match in the Troposphere.

The HUGE clouds

The cumulonimbus and the nimbostratus: Lots and lots of water vapor.

Pen
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