Water is naturally tinted with a slight blue, but sediments and organics can alter its color

Wood that changed the color of water was the earliest recorded example of fluorescence

Lignum nephriticum, a tea used to treat kidney and urinary illnesses, was described in the 16th century as derived from white wood that turned water a bluish hue. However, in the 17th century, accounts described the wood as reddish and creating a kaleidoscope of colors in water. In 1915, the sources were identified as two different woods, which absorb UV radiation and emit visible light.

View the rainbow effect on the waters at First Landing State Park

The phenomenon results from light interacting with a thin film of natural oils on the surface of swamps and marshes at the site, not unlike the coloration seen in soap bubbles. The oils originate from decaying vegetation or from anaerobic bacteria reducing iron in soil. (Some readers may experience a paywall.)

Massive blooms of microscopic plankton called dinoflagellates produce the neon blue light seen in glowing tides.

Massive blooms of microscopic plankton called dinoflagellates produce the neon blue light seen in glowing tides.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

A diamond's color comes from impurities, defects, and unique formation processes

While most diamonds are transparent and sparkly, the presence of nitrogen and boron during formation can make them yellow, orange, or blue. Radiation can produce green diamonds, and structural deformities can introduce red hues.

From the surface, Mars can appear butterscotch, golden brown, and even green

Images from orbiters, landers, and rovers show that Mars has a mix of surface colors resulting from variations in the mineral compositions of different regions. The reddish tint when viewed from Earth comes from kicked up particles of rusted iron.

Atmospheric composition and temperature impact the color of lightning

Just as fire ranges from red to blue with increasing temperature, lightning's blueish-white comes from the superheating of air. The emission of light from the predominantly nitrogen- and oxygen-rich atmosphere produces a purple tint, with additional color caused by light scattering from humidity, hail, dust, and ash.

What is the rarest color in nature?

Plants, animals, or minerals found in nature bear almost every color imaginable. There are two factors that influence what hues you see in the wild: physics and evolution. So, which colors are you least likely to see in the natural world? Victoria Hwang explores one of nature’s rarest spectacles.

The chlorophyll in plants captures energy in the form of red and blue light

Light-dependent reactions during photosynthesis convert sunlight into chemical energy, stored within the bonds of molecules such as ATP and NADPH. Rather than being absorbed for these reactions, most green light is reflected, causing most plants to appear green.

Melanin and light scattering contribute to different eye colors

Brown eyes have high melanin, while blue eyes have low melanin. Multiple genes contribute to eye color, which can change over time due to melanin buildup. Hazel eyes can shift color depending on ambient light.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

The color blue is almost never mentioned in ancient Greek literature

Linguists have noted blue is regularly the last color to enter the language of most cultures. Researchers guess that the color's rarity in living organisms is partly the cause of its linguistic absence.

Copper is responsible for turning blonde hair green in swimming pools

Pools use copper sulfate to control algae, which can bind to hair either damaged by the sun or recently bleached. Chlorine, which is often considered to be the culprit, weakens the hair structure to exacerbate the green coloration reaction, rather than causing it.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Eggshell color doesn't indicate taste or superiority

Brown, white, and blue eggs taste and cook identically. Despite popular notions that brown eggs are superior, the shell color reflects the genetics of the hen alone. What actually determines egg quality is freshness and the diet of the hen (where grass and leafy greens lead to denser yolks). And freshness can go both ways: older eggs peel more easily than fresh ones.

Relative motion between a source and an observer shifts the color of observed light

The phenomenon, known as the Doppler effect, is the result of experiencing an increase in the frequency of observed waves when approaching a source and a decrease when moving away. Because this property corresponds to color, approaching objects appear bluer than normal—blueshift—and receding objects appear redder than usual—redshift.

Egyptians called the Nile River the 'Ar,' meaning 'black'

The over 4,000-mile river would turn dark during its warm-season flooding as sediments flowed downriver. This nutrient soil, which would settle on the riverbank, was essential for farming in Egypt.

Without liver bile, human poop would be a pale silver color

Stomach acid and enzymes break down food into smaller particles, expelling a semi-fluid mass called chyme into the small intestine, where bile is added. As the intestines absorb nutrients and water, the chyme solidifies and changes color.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

Exploring the microscopic composition of blood

Visually, blood looks like a single, red fluid. Zooming in, it is one of the richest substances known, with hemoglobin, plasma, proteins, red and white blood cells, platelets, and more.

Pigments in paint can come from rocks, plants, insects or synthetic sources

Paint's composition is varied through the combination of pigments with binding agents. In the past, artists created their own paints by mixing pigments with water, oils or egg yolks to bind the colors together.

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

A viral photo of a dress sparked a fierce online debate over its colors

A post showing a dress sparked a heated social media divide, with some insisting it was white and gold and others insisting it was blue and black. The debate quickly spread to celebrities and brought in scientists to explain the optical illusion.

Why so many cartoons are yellow

"The Simpsons" creator Matt Groening said he found the skin tones of cartoon characters to be "freakish" and wanted his show to stand apart from everything else on television. His colorist proposed making them yellow, which color theory suggests would make the characters pop off the screen.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

About 1,500 species of tardigrades have been identified by their unique physiology

Freshwater-bound eutardigrades live on mosses and lichens and are distinguished by variations in the shape and number of claws at the end of their legs. Marine heterotardigrades, which live on algae and deep-sea sediments, have been observed to possess feathers, inflatable appendages, and flagpole-like tails.

Layers in sediment cores hold clues to Earth’s past climate

By analyzing materials such as pollen and algae within the layers of these cores, which are collected from lakes and oceans, scientists can learn what the environment and climate were like when that layer formed.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

Tattoos remain visible on your skin thanks to immune cells called macrophages

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

Brian Wilson wrote the Beach Boys' 'Don't Worry Baby' for the Ronettes, but the legendary girl group rejected it.