Essay Example on This experiment is to determine what part of the light spectrum the spinach extract Absorbs









Measuring visible light absorbance Lab Report by Purpose The purpose of this experiment is to determine what part of the light spectrum the spinach extract absorbs the most Hypothesis My hypothesis is that the spinach extract will absorb the most red purple and blue light and will not absorb much green or yellow light Reason for my hypothesis The reason for my hypothesis is that because we see spinach as green it is absorbing all light except green and therefore the spinach extract would absorb the least amount of green and the least amount of red or purple which is the opposite to green on the color wheel Materials 1 Spinach plant at least 1g 2 Mortar 3 Pestle 4 20 ml of 70 isopropyl alcohol 5 Funnel 6 Filter paper 7 Spectrovis plus spectrophotometer 8 Computer will the proper data collection program installed 9 Empty Cuvette 10 Time measuring device Method Refer to handout Results Refer to graph Statement of Learning What I learned from performing this experiment is that organisms such as plants appear to be a certain color because they absorb all the light in the visible light spectrum except the ones they reflect which is what you see For example the spinach in the experiment did not absorb much green light in the light spectrum because that is what is most reflected Safety considerations None Analysis Questions 

1 Spectrophotometry is a method of measuring how much a substance absorbs light by measuring the intensity of light passing through a sample of that substance This is going from the knowledge that every substance absorbs or transmits light of a specific wavelength The spectrophotometer works by generating a beam light that passes through a prism which separates the light beam into all the visible light spectrum The light then passes through the sample solution and hits the photometer which measures the photons light intensity that got through 2 The reason you calibrate the spectrovis with isopropyl alcohol is to set the spectrophotometer to zero like calibrating an electronic scale This allows the spectrovis to record the photons that passed through the cuvette with isopropyl alcohol to use as a point of reference to when you put the solution you want to test in and subtracts it from the result Without this the spectrophotometer would record the absorption by the isopropyl alcohol in addition to the sample 3 The visible light absorbance spectrum of the spinach extract was highest in the dark blue purple and red areas and lowest in the green yellow and orange areas The peaks were at around 250 nm and 600 nm 4 What the spinach extract absorbing at a particular wavelength means is that the pigments in the spinach absorbs all colors except the wavelengths it reflected and the wavelengths it absorbed the most were the most unlike the spinach color green which had one of the lowest absorption rates 

5 The advantage that a plant would obtain from having more than one pigment would be that it could maximize the energy from the sun by capturing more than one wavelength of light For example based on the results obtained from this experiment the spinach had 2 pigments absorbing both red and blue purple light 6 Yes I suspect plants growing in varying geographical locations might hold different pigments because the pigments in plants are chosen to maximize efficiency by absorbing a particular wavelength at a particular intensity Therefore the plants in regions where light is sparse or there is a lot of a certain wavelength available the plant with the appropriate pigments will thrive and live there Optional Questions 1 Some other applications of spectrophotometry include biochemistry where the spectrophotometer is used to find enzyme catalyzed reactions and in clinical applications where it is used to analyze blood or tissues to predict foreseeable problems 2 The chemical makeup and structure of other plant pigments such as carotenoids absorb mostly blue light and reflect yellow light Carotenoids can be up of carotenoids such as ß carotene which is produced in the chromoplasts of ray flowers and gives them their yellow color Their chemical makeup includes a repeating branched unit made up of five carbons The carotenoid structure also has conjugated double bonds that give the Carotenoids its light absorption property

Another pigment is anthocyanin which absorbs light majorly in the blue green wavelengths giving it a red appearance This pigment produces the color of fruit in things such as red apples and plants 3 Some plant flowers fruits leaves and other parts of plants whose extracts might be of interest could include bananas strawberries Astilbe hybrids Swamp Tupelo Tree Leaves and Blue Hydrangea flowers Conclusion The data I gathered supported my hypothesis that the spinach extract would absorb the most red and violet light Works Cited Leaf Pigments Leaf Pigments Harvard Forest harvardforest fas harvard edu leaves pigment Libretexts Spectrophotometry Chemistry LibreTexts Libretexts 21 July 2016 chem libretexts org Core Physical_and_Theoretical_Chemistry Kinetics Reaction_Rates Experimental_Determination_ of_Kinetcs Spectrophotometry Wallace Mary O What Is Spectrophotometer Calibration WiseGEEK Conjecture Corporation 30 Dec 2017 www wisegeek org what is spectrophotometer calibration htm didyouknowout Why Is the Chlorophyll in Plants Green or Even Red Orange or Brown UCSB Science Line scienceline ucsb edu getkey php key 1110 Plant Pigments and Photosynthesis Plant and Soil Sciences ELibrary passel unl edu pages informationmodule php idinformationmodule 939154129 topicorder 4 maxto 10

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