Science Skills Station Objective Analyze the effects of sunlight intensity on the rate of photosynthesis. Determine the importance of carbon dioxide on the rate of photosynthesis. Skills Utilized Infer and/or Predict Identify variables Analyze & interpret data Compare and contrast Determine relationships Graph data Activity #1 A student investigates the effect of sunlight intensity on the rate of photosynthesis. She places a plant in a closed container. She maintains the concentration of carbon dioxide and temperature but exposes the plant to varying intensities of sunlight. She measures the rate of oxygen produced by the plant. Light Intensity Temperature CO 2 Concentration O 2 Output Rate 0% 30 C 500 ppm 0 ml per hour 10% 30 C 500 ppm 8.2 ml per hour 15% 30 C 500 ppm 12.6 ml per hour 20% 30 C 500 ppm 17.1 ml per hour 25% 30 C 500 ppm 21.6 ml per hour 30% 30 C 500 ppm 26.1 ml per hour 35% 30 C 500 ppm 30.5 ml per hour 40% 30 C 500 ppm 31.3 ml per hour 45% 30 C 500 ppm 31.3 ml per hour 50% 30 C 500 ppm 31.3 ml per hour Directions: Graph the rate of oxygen produced at varying light intensities. Create a scale and label your axes. Title your graph. Then answer the questions. Questions: 1. How does the oxygen output rate help us understand the rate of photosynthesis? 2. What is the relationship between light intensity and the rate of photosynthesis? 3. Predict the oxygen output rate at 5% light intensity. 4. Do you think a plant could perform photosynthesis on a cloudy day? Explain. 5. Identify the controlled, independent and dependent variable in this experiment. 7
Science Skills Station cont. Activity #2 The student decides to conduct a second experiment. She investigates the effect of carbon dioxide concentration on the rate of photosynthesis. She varies the concentration of carbon dioxide but keeps temperature and the intensity of light the same. She measures the rate of oxygen produced by the plant. Light Intensity Temperature CO 2 Concentration O 2 Output Rate 40% 30 C 0 ppm 0 ml per hour 40% 30 C 50 ppm 5.4 ml per hour 40% 30 C 100 ppm 11.2 ml per hour 40% 30 C 150 ppm 17.2 ml per hour 40% 30 C 200 ppm 23.4 ml per hour 40% 30 C 250 ppm 29.4 ml per hour 40% 30 C 300 ppm 31.3 ml per hour 40% 30 C 350 ppm 31.3 ml per hour 40% 30 C 400 ppm 31.3 ml per hour 40% 30 C 450 ppm 31.3 ml per hour Directions: Graph the rate of oxygen produced at varying carbon dioxide concentrations. Create a scale and label your axes. Title your graph. Then answer the questions. Questions: 1. What is the relationship between carbon dioxide and the oxygen output rate? 2. The concentration of carbon dioxide at sea level has been over 375ppm for more than ten years. How does this impact the rate of photosynthesis of plants on Earth? 3. How might the oxygen output rate be impacted in this investigation if the light intensity was kept constant at 10% instead of 40%? 4. Identify the controlled, independent and dependent variable in this experiment. Summary Questions: 1. Why is it important to change only one variable in each experiment? 2. Why does the oxygen output rate max out in each experiment? What might be impacting the plant s ability to produce more oxygen? 3. What material isn t discussed in the experiments but is vital to photosynthesis? How would photosynthesis be affected if the material was omitted from the experiments? 4. What other substance could you measure to determine the rate of photosynthesis? 8
Narrative Station Objective 1. Identify the reactants and products of photosynthesis. 2. Explain how a plant obtains the reactants needed for photosynthesis and uses the products of photosynthesis. 3. Discuss the importance of photosynthesis in the cycling of energy and matter between living things on Earth. Skills Utilized Answer questions relating to a text Cite textual information Summarize information Make connections Evaluate facts, reasoned judgement, speculation Directions: 1. Read each informational text. 2. Answer the summary questions following the text. 9
Activity #1 Narrative Station cont. PHOTOSYNTHESIS Plants make their own food through a process called photosynthesis. Photosynthesis is a chemical reaction in which energy from sunlight is used to make food, specifically glucose. In photosynthesis, raw materials (reactants) are converted into products. We summarize the reaction of photosynthesis in an equation: Water + Carbon Dioxide + ENERGY (SUNLIGHT) à Glucose + Oxygen The reactants in photosynthesis are carbon dioxide and water. A plant absorbs water in soil with its roots and carbon dioxide gas in the air with its leaves. Sunlight is a catalyst for photosynthesis. It provides energy to power the reaction of photosynthesis. Sunlight is absorbed by chlorophyll. Chlorophyll is a green pigment in the chloroplasts of plant cells. Chloroplasts accommodate the process of photosynthesis. The energy absorbed by chlorophyll is used to convert carbon dioxide and water into glucose and oxygen. The products of photosynthesis are glucose and oxygen. Oxygen is released through tiny pores in the leaves of plants. Animals, including humans, take in oxygen produced by plants. On the other hand, plants do not release glucose. Plants use glucose to fuel activities in the plant, such as growth and reproduction. They also use glucose to build plant structures. Plants convert glucose into cellulose. Cellulose is used to construct the cell wall of new plant cells. Plants store glucose as well. They store glucose as starch. Plants use the starch as stored energy at a time when conditions are not optimal for performing photosynthesis. Starch can be converted back to glucose and used as energy. Plants do not perform photosynthesis at night; they only perform cellular respiration. Cellular respiration is the process of converting oxygen and glucose into energy. Plants carry out cellular respiration during the day as well. This is how plants use glucose for energy. They convert glucose into a usable form of energy needed for plant activities. Although plants use some oxygen during the day, they produce more than they consume. This is important because animals rely on plants to produce the oxygen to survive. Questions: 1. Identify the reactants and products of photosynthesis. 2. How is chlorophyll important to the process of photosynthesis? Is it a reactant? 3. How does a plant depend on glucose to survive? 4. Why can t a plant perform photosynthesis at night? 10
Activity #2 Narrative Station cont. PHOTOSYNTHESIS AND THE CYCLING OF ENERGY AND MATTER Photosynthesis is important to the cycling of energy and matter between the physical environment, plants and animals. Photosynthesis uses energy from the sun to convert simple, nonfood molecules in the environment into food molecules. Food molecules are used by a plant or consumed directly or indirectly by animals. Photosynthesis requires sunlight, carbon dioxide and water. Sunlight provides the energy necessary to convert carbon dioxide and water nonfood molecules into food molecules. In this process, light energy from the sun is transformed into chemical energy of food. Glucose, and thus chemical energy, can be used immediately by a plant (to fuel its life process or build plant structures) or stored for later use. Glucose is important to not just plants; it is important to ALL living things. Animals use energy in glucose to fuel all the different processes that keep the organisms alive. Animals take in glucose directly or indirectly from plants. Some animals feed on plants and directly consume glucose. Specifically, they consume glucose stored in the plant. Other animals feed on the animals that fed on plants and indirectly consume glucose. Plants also produce oxygen in the process of photosynthesis. Animals take in oxygen. They use oxygen to extract the chemical energy in glucose. Without oxygen, animals cannot use glucose and thus, would not survive. Questions: 1. What does the reading mean when it says Photosynthesis uses energy from the sun to convert simple nonfood molecules in the environment into food molecules? 2. How is energy transformed in the process of photosynthesis? 3. Some animals are carnivores. Carnivores are organisms that eat other animals but not plants. Can these organisms survive without plants? Explain. 4. If plants only produced glucose as a product of photosynthesis, would animals be able to survive? Explain. 11
Assessment Station Objective Recall concepts, terms and ideas relating to photosynthesis. Skills Utilized List steps to a process Explain a concept Determine relationships Make predictions Illustrate a concept Assessment Direction 1. Answer the following questions. Write down your answers on the recording sheet. 2. There are two bonus questions. If time allows, try to answer these questions. 12
Question #1 Write the equation for photosynthesis. Identify the reactants and products in the equation, as well the source of energy that powers the process of photosynthesis. Question #2 True or False. Oxygen is completely useless to a plant. Question #3 Some organisms, such as the bacteria and protists of algae, have chloroplasts. Can these organisms perform photosynthesis? Explain. Question #4 How does a plant use the food it produces from photosynthesis?
Question #5 What might happen to animals on Earth, including humans, if the sun stopped shining? Question #6 Below is a illustration of the an animal, a plant and the sun. Draw arrows to how energy and matter are cycled into and out of organism as a result of photosynthesis. BONUS Question #7 Chlorophyll is the green pigment in plants that is important photosynthesis. Do you think all green organisms, such as grasshoppers and lizards, can make their own food? Explain. BONUS Question #8 In the fall, the leaves of trees turn red, yellow and orange. Then the leaves fall off the tree. What is occurring inside the leaves? How does this impact a tree s ability to perform photosynthesis?
Problem Solving Station Objective Create a physical model that illustrates the role of photosynthesis in the cycling of matter and flow of energy in a plant. Skills Utilized Develop a model Overview Plants make their own food through a process called photosynthesis. Photosynthesis is a chemical reaction in which energy from sunlight is used to make food, specifically glucose, from carbon dioxide and water. In this activity, you will build a model to illustrate the process of photosynthesis. Use the templates in your recording packet to help you. The model must adhere to the following: Identify the reactants and products of photosynthesis Distinguish between food and nonfood molecules Use arrows to show the flow of energy going into or out of the leaf Use arrows to show the cycling of matter going into and out of the leaf Include structures, such as chloroplasts, important to photosynthesis in a leaf Directions: 1. Cut out the leaves and arrows. 2. Glue the base of the leaves together in the section GLUE THIS AREA. Use the region between the leaves to represent the inside of a leaf. 3. Use the arrows to show cycling of matter and flow of energy in a plant leaf. Write on the arrows to describe the substance cycling into and out of the leaf. 4. Include additional structures and information to better model photosynthesis. 5. Answer the questions. Questions: 1. How does a model help you better understand the importance of photosynthesis in the cycling of matter and flow of energy? 2. How is this model limited in its ability to help you understand photosynthesis? 3. Why might it be useful to include animals in this model? 4. If provided unlimited resources, how would you improve the model so to summarize photosynthesis better? 15
Problem-Solving Station Photosynthesis Lab Recording Sheet GLUE THIS AREA GLUE THIS AREA 26