Photosynthesis Experiment MATERIALS NEEDED 1 - medium tall clear cup or glass 1 - drinking straw 1 - coffee filter cut into a 1 inch wide strip 1 - Blue felt tip pen (non-permanent ink) 1 – Red felt tip pen 1 – Black felt tip pen 1 - teaspoon baking soda 1 – large leaf red cabbage 1 - small cooking pot PAPER CHROMATOGRAPHY This experiment will involve the separation of pigments. Because of the hazardous chemicals used in a traditional lab, plant pigments will not be separated but instead the pigments found in ink. The technique of separating pigments is called Chromatography. Chromatography separates molecules from each other based on their solubility to certain solvents or how well the molecules attract to the solvent (polar vs. nonpolar). The solvent used in this experiment will be tap water. Ink is made by the combination of different colors. Pigments found in ink are (unless synthesized in a laboratory) extracted from plant pigments then combined to make the different ink colors. 1. Obtain a coffee filter and cut the middle of the filter length wise and about 1 inch in width. 2. With the Blue felt tip marker, place a dot (good size) about 1 inch from the bottom of the filter paper strip. 3. Make sure the filter strip will touch the bottom of the glass and still have enough at the top of the filter strip to attach to a straw. 4. Place enough tap water into the glass so that the end of the strip touches the water but the felt tip marker dot is not immersed. 5. Tape the other end of the filter strip onto the drinking straw so that the filter strip remains upright yet still touches the water. 6. Place the straw horizontally across the rim of the glass. 7. Let stand for approximately 10 minutes. 8. Observe and record your results on the Photosynthesis Worksheet. 9. Repeat this experiment with the Red felt tip pen. 10. Repeat this experiment with the Black felt tip pen 11. Record your results for each. EVIDENCE OF OXYGEN RELEASE 1. After completing the Chromatogram, remove the filter strip and thoroughly rinse the glass. 2. Fill the glass three fourths full with water. 3. To the water add 1 teaspoon of baking soda and stir to dissolve the baking soda. 4. Obtain one or two green broad leaves from a tree or shrub. It is not recommended that the leaf be thick. Try to obtain a thin leaf such as a maple or crape myrtle leaf. 5. Place the leaves into the baking soda solution in the glass. 6. Place the glass in sunlight. 7. Let stand for approximately 20 minutes. 8. Observe and record your results onto the Photosynthesis worksheet. MAKING A pH INDICATOR 1. Obtain the red cabbage leaf and place into the small cooking pot. 2. Add about 1/2 cup of water to the leaf in the pot. 3. Boil the leaf for 3 or 4 minutes but do not let the water totally evaporate while boiling. 4. Pour off the cabbage water and let cool. 5. To the cabbage water, add enough cold tap water to make the solution violet to pinkish in color. CARBON DIOXIDE UTILIZATION When carbon dioxide is added to water, it forms carbonic acid. In the presence of an acid, the cabbage pH indicator water should turn yellow. 1. From the Evidence of Oxygen Release experiment, remove the leaves from the baking soda solution and rinse the leaves with tap water. 2. Empty the baking soda solution from the glass and rinse the glass. 3. Return the leaves to the empty glass. 4. Add enough cabbage water to the glass to cover the leaves. 5. Obtain the straw used in the chromatography experiment. 6. Place the straw into the cabbage water and blow into the water (Not so hard that water splashes out of the glass). 7. Record the color change onto the Photosynthesis Worksheet. Click here to view a slide of the lower leaf epidermis and stomata. Instructions for Biology Laboratory Reports NOTE – ALL LAB REPORTS MUST BE SUBMITTED THROUGH TURN-IT-IN. A complete laboratory report should follow the general form used in writing a professional scientific paper. The material in the report should be organized into six sections. Your lab report must contain the sections indicated below. With the exception of the title page, each section (intro, methods, etc.) should be labeled to make your report easier to follow. Title Page: You should have a title that is limited to your subject matter, but as descriptive as possible. Avoid overly general titles, ex. "The termites". A more appropriate title might be, "A demonstration of ink preferences in wood-dwelling termites". This page should also include a list of your fellow experimenters. While you will complete the experiments in groups, each student must individually complete and write his or her own lab report. Introduction: This section should introduce the topic of your experiment and should include any PERTINENT background information needed to understand the experiment. Cite references for background material where appropriate. At the end of this section, you should state the major objective or purpose of your experiment (this should be concise) and clearly state your hypothesis. Materials and Methods: In this section, you should describe the materials used and the EXACT procedures that you followed while performing your experiment. If you used a different procedure than listed in the lab manual, you should describe the procedure that you actually used. A person should be able to read this section and perform your experiment exactly the way you did. Do not give the results of your experiment in this section, only materials and procedures. Results: This section should include 2 parts: 1. a written description of the results in the body of the paper, 2. a graph(s) or table(s) on a separate page displaying the results. Do not explain or comment on the significance of the results here, just give the data. Every table or graph must have a descriptive title ("termite data" is not descriptive enough) and labeled axes with units of measure clearly indicated. Tables consist of columns and rows of numbers or other information and should be numbered in sequence and referred to in the written results section, ex. "Termites followed the red ink for an average of 5 seconds (Table 1)." Graphs are called figures and are referred to in the same manner, ex. Fig.1. Discussion: In this section, you should indicate if your hypothesis was supported, explain your results, and indicate the significance of the results. A hypothesis cannot be proven by a single experiment. You should interpret your results as "supportive of" or "failed to support" the hypothesis. To the best of your ability, you should explain what was occurring during your experiment, why you got the results that you did, and any possible sources of error. You should also indicate the significance of your results. How might this information be used? What are the implications of your results? Lastly, you may want to develop further experiments that might be used to lend more support to the hypothesis, or develop a totally new hypothesis based on your results. Literature cited: Whenever you cite a fact or an idea, cite the reference giving credit to your sources. This should be done in the body of the report so that it is clear to the reader. For example: "That cytochrome included three distinct enzymes was first shown by Keilin (1925)" or "It is known that cytochrome consists of three distinct enzymes (Keilin, 1925)." The literature cited section consists of a list of references which should include the author`s name, initials, year of publication, journal, specific volume, and the pages. For example: Keilin, D., 1925. Proc. Rev. Soc. London, B98: 312-329 When referencing books use the following form: Eckert, R., and D. Randell, 1978. Animal Physiology. 1st ed. W.H. Freeman and Co. 510 pp. Additional points: 1. The report should be concise. Four to six typewritten (double spaced) pages should be sufficient. 2. Avoid the first person, ex. "the termites were placed on the paper, and the time each termite followed each line measured with a stopwatch" not "Suzi placed the termites on the paper, and I timed how long each termite followed the lines". 3. Use precise English and avoid useless words such as "First,...Next,...Then,..." or "then we proceeded to". 4. Use complete sentences with good grammar and spelling. Content: 80% INTRODUCTION: 25% * Introduces the topic of the experiment with sufficient background to exhibit a clear understanding of the material covered. * States major objectives clearly. * States HYPOTHESIS properly MATERIALS AND METHODS: 10% * Includes all materials used through the entire experiment * Describes all procedures as they were performed (NOT as a recipe or as written in the lab manual) RESULTS: 15% * Explains clearly and concisely, in paragraph form, data and observations * Displays relevant graphs/tables/diagrams * References all graphs/tables/diagrams in the written portion of the RESULTS * Includes only results (no interpretation of data or conclusions) DISCUSSION: 30% * Discusses how results support or fail to support hypothesis, and implications * Explains possible sources of error * Describes how information might have practical uses * Formulates further experiments to test hypothesis, or proposes a new hypothesis and experiment (based on observations in current experiment) Format: 20% GENERAL: 15% * The report has a descriptive title * Materials are written in paragraph form * Each graph/table has a descriptive title * Axes of graphs are properly labeled * Sections are properly titled * Length is 4-6 double-spaced pages * References are cited correctly in the paper and in LITERATURE CITED * The report and each section are logically organized ENGLISH: 5% * Grammar, syntax, spelling, and punctuation are used correctly and consistently * The report is written in third person (first person may be acceptable – ask your instructor)