|
Abstract Are all reds the same? Find out in this science fair project! Investigate if the pigments in one type of red flower are different from those in another type of red flower. Flowers contain an assortment of amazing chemicals that produce color. In this plant biology science fair project, you will analyze the colored pigments in different plants' red flower petals using paper chromatography, and compare the pigments in the different flowers.Objective The objective of this plant biology science fair project is to analyze the pigments in red flower petals, and to determine if different red flowers use the same or different pigments. Introduction Plants contain many complex chemicals. Some of these chemicals are used in the normal metabolism of the plant, such as those involved in photosynthesis. Some are involved in the plant's defense against insects, bacteria, and other pathogens. And some, such as the pigments in a flower, are involved in attracting the attention of possible pollinators, such as honeybees, butterflies, and hummingbirds. The major types of flower pigments are anthocyanins, flavones, and carotenes. The anthocyanins produce red, purple, and blue colors; the flavones produce pale yellow colors; and the carotenes produce yellow, orange, and red colors. Usually, the color of the flower depends on the color of the pigments found in the flower. But there was a century-old mystery that defied this logic. Cornflowers, which are blue, appear to have the same pigments as roses, which are red. How could this be explained? It turns out the difference is due to way the pigment molecules are organized inside the flower petal. The pigment that is red in the rose is blue in the cornflower because of the chemical environment within the cornflower (for more information about this, see the article by Steve Conner in the Bibliography, below). This occurrence is a good example of how, in nature, new and unexpected characteristics can emerge from the organization of simple parts. The goal of this plant biology science fair project is to analyze the pigments found in flowers using paper chromatography. Paper chromatography is a technique to separate molecules, such as a mixture of pigments. The concept is shown in Figure 1, below. A mixture is dabbed onto a piece of chromatography paper near one end, at a point called the origin (See Figure 3). The same edge as the mixture dab is immersed in a solvent, with the origin above the level of the solvent. The paper works like a wick, with the solvent moving up the paper, due to capillary action. The pigment molecules are then carried up the paper with the moving solvent. The rate at which different pigments move depends on a number of factors, including their size and solubility in the solvent. If a pigment is small and very soluble in the solvent, it can be carried up the paper with the solvent front, which is the leading edge of the solvent, as it travels up the paper. Because different pigment molecules have different chemical characteristics, they are separated from each other on the chromatography paper.
How can you compare how far a pigment has traveled in two different experiments? It is possible to compare the results of different experiments if the distance that the pigment travels is given as a fraction of the distance that the solvent front has traveled. The relationship of the distance moved by a pigment to the distance moved by the solvent front is specific for a given set of conditions. This relationship is called the Rf, and is defined as follows: Equation 1:
You will use paper chromatography to analyze the pigments in red flowers from different species. Do you think they will have the same pigments, as determined by paper chromatography, or will the pigments be different? Terms, Concepts, and Questions to Start Background Research
Questions
Bibliography
Materials and Equipment
Experimental Procedure To make sure you can compare your results, as many of your materials as possible should remain constant. This means that the temperature, type of water used, size of paper strips, where the ink is placed onto the paper, etc., should remain the same throughout the experiment. Cutting and Marking the Paper Strips
Spotting the Sample onto the Paper
Placing the Strip into the Chromatography Chamber
Analyzing Your Data
Variations
Credits David B. Whyte, PhD, Science Buddies
|
If you like this project, you might enjoy exploring related careers.
![]() |
Biochemist Growing, aging, digesting—all of these are examples of chemical processes performed by living organisms. Biochemists study how these types of chemical actions happen in cells and tissues, and monitor what effects new substances, like food additives and medicines, have on living organisms. |
![]() |
Agricultural Technician As the world's population grows larger, it is important to improve the quality and yield of food crops and animal food sources. Agricultural technicians work in the forefront of this very important research area by helping scientists conduct novel experiments. If you would like to combine technology with the desire to see things grow, then read further to learn more about this exciting career. | |
![]() |
Plant Scientist With a growing world population, making sure that there is enough food for everyone is critical. Plant scientists work to ensure that agricultural practices result in an abundance of nutritious food in a sustainable and environmentally friendly manner. | |||
|
Join Science Buddies
Become a Science Buddies member! It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives. |