In this activity we will explore the wild world of chlorophyll to see how many naturally occurring shades of green exist even during late winter and early spring. So grab a handful of your favorite green snack, and let's go green!

Ok, so now we know WHY plants are green and how plants use the chlorophyll to promote photosynthesis, but that still doesn't explain the different shades of greens ranging from light green to a dark mottled green. Have you ever wondered why this happens? I mean, GREEN isn't always GREEN if you know what I mean? Take a look below, those are all shades of "green". Why does this happen?

Habitat (where the plant lives and how much sunlight it gets)

• Plants that get limited sunlight end up being darker and have a higher concentration of chlorophyll b. Chlorophyll b is much better at collecting energy from low intensity sunlight.

• Plants that get a lot of sunlight end up being a lighter shade of green, because they have a higher concentration of chlorophyll a.

Leaf Design (thick leaves vs. thin leaves)

• This gets tricky - you have thick "dry" leaves (like a rhododendron) and you have thick "wet" leaves like a cactus.

• Thick/dry leaves tend to be darker, because they have more density of the things that hold the chlorophyll (chloroplasts).

• Thick/wet leaves are lighter, because they are watery and have the chloroplasts spread throughout the leaf.

Leaf Age (young/new leaves vs. older mature leaves)

• Young leaves have yet to develop a fully functioning cell wall, and they don’t have the mechanisms for achieving photosynthesis as efficiently. This gives them a much lighter color.

• As most leaves mature, these systems become fully operational and produce a much darker color later in their life cycle.

Plant Deficiencies (the overall health of the plant)

• Just think about it, when you get sick, you can change color too! Plants are not different. Nutrient deficiencies, such as low levels of nitrogen, magnesium and iron, can make the plant go yellow or yellowish-green.

What’s green and has wheels?

Grass.

I lied about the wheels.

Outdoor Adventure Challenge

*Teachers, this activity is an adaptation of one found in Schoolyard Enhanced Learning by Herb Broda.

We have learned a TON about plants and why they are various shades of green, but let's see if we can find any of these various shades in late winter and early spring. Here is your challenge:

• Select one of the varying levels of Shades of Green card below (Not Spicy, Medium Spice, or Holy Wow - That's Spicy).

• Print it out, if possible. If not, click the image to get the full view and take a picture of it with your phone or iPod/iPad.

• Take this image outside and see how many of the shades you can find. 

• You can pick a small piece of the leaf/plant to keep as your sample, but be sure not to get carried away - you don't need a piece bigger than your thumbnail.

• If you finish Not Spicy, notch it up and see if you can tackle Medium Spice or even Holy Wow!

• With the range of shades in greens, consider what might have caused this to occur. Was it:

  • Habitat?

  • Design?

  • Age?

  • Deficiency?

• When you are done, come back so we can do the Reflection and Quick Quiz below.

• HAVE FUN!

Review and Reflection

Congratulations on your discovery of a wide and amazing array of green-ness in your own neighborhood! Who would have thought that at such an early part of the year that there would be soooooo much green! That is all thanks to the amazing relationship between chlorophyll and photosynthesis and the varying densities of chlorophyll a and chlorophyll b. Based on what you did today, consider the following questions and share your answers with anyone who will listen!

1. Which of the four factors of leaf color was most present in your samples? Was it habitat, design, age, or deficiency? Why do you think this is so?

2. How would our world be different if plants started absorbing green and not another color? What would change in our daily lives?

3. Will completing the Holy Wow - That's Spicy grid be easier or harder in June? What about October?

Quick Quiz

It's go time! You have done all the hard work, now let's see how much you remember from your adventure into the green. Feel free to look back and review for each of the questions. Good luck!

About the Author

Matthew

Dr. Matthew Broda is an Assistant Professor of Education at The College of Wooster and is currently on sabbatical studying innovative pedagogies. His research and teaching interests include instructional technology, outdoor, and experiential education. When not teaching his students, he can usually be found somewhere outside – smiling.