In the very first Wonder of the Day, we learned that flamingos are pink because of pigments called carotenoids found in the shrimp they eat. Carotenoids are also found in red, orange, and yellow foods, such as carrots, tomatoes, and egg yolks.

Much like flamingos and carrots, grass contains a special pigment that gives it a green color. This pigment is called chlorophyll.

Chlorophyll is used during photosynthesis. Photosynthesis is a process that takes places when a plant uses sunlight to turn carbon dioxide and water into sugar. Unlike animals, which have to hunt for their food, plants can create their own food using sunlight. If you remove most plants from sunlight, they cannot produce food and will eventually die.

So what makes chlorophyll green? Every object on Earth has its own color. The light from the sun appears white, but is actually made up of a full spectrum of colors: red, orange, yellow, green, blue, indigo, and violet.

When white light hits an object, the object absorbs some colors and reflects others. When we look at an object, the color we see is the color the object reflects. The sky absorbs all the colors except blue, which it reflects. This is why the sky appears blue on a sunny day.

Think about the last time you played kickball with a group of friends. The red rubber ball absorbs all the wavelengths in white light except red. As you watch the red ball bounce along the ground, your eyes see the ball reflecting red light. Your eyes send this information to your brain, which tells you the ball is red.

Similarly, grass appears green because it absorbs all the wavelengths of white light except green. Green is reflected off the grass. When the green wavelength reaches our eyes, we see grass as green.

Wonder What's Next?

Tomorrow’s Wonder of the Day was once alive, but is now hard as a rock!