Photosynthesis Performance Task Name _______________________ Standard: HSLS15 Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy Introduction: Photosynthesis converts light energy into stored chemical energy. While carrying out these virtual labs, you will determine the inputs and outputs of photosynthesis, and experiment how different variables affect the rate of photosynthesis. Background: http://www.harcourtschool.com/activity/science_up_close/512/deploy/interface.html Use this interactive to help you determine the inputs and where the plant gets these materials. Start by completing this table, and you may use the interactive to help you. INPUT for Photosynthesis Where it comes from in nature Light Roots get it from the soil Carbon Dioxide When the sun shines on a leaf, ____________________ inside the leaf (that also makes it green) absorbs the energy from the light. A chemical reaction occurs that changes the water and carbon dioxide into ______________ and _______________. The energy from the light is ultimately stored in the ____________. Cells in the plant can break down the sugar later to get the _____________ which originally came from the ______. The plant does not need the ____________ so it releases it into the air. Photosynthesis is important for plants because it is how they make their __________. It is important for people and animals because it is how we get the ____________ we breathe. When you eat _________ or _____________ you get energy from plants for your cells that was once energy from the ________! Virtual Lab #1 http://www.reading.ac.uk/virtualexperiments/ves/preloaderphotosynthesisfull.html 1. Before you begin collecting data, hypothesize how light intensity will affect the rate of photosynthesis. Will higher light intensity lead to a higher or lower rate of photosynthesis? Bubbles are given off by the plant through photosynthesis. What are these bubbles made of? ___________________ By measuring the rate at which the bubbles are produced it is possible to tell how fast the plant is photosynthesizing. Read and follow the directions on how to use this lab simulator. Press start and record the bubbles per minute for each of the following light distances. Then graph your data. (be sure to label each axis). Light Distance (cm) Bubbles per minute 100 120 150 180 200 Virtual Lab #2 http://www.kscience.co.uk/animations/photolab.swf 3. Before beginning this lab, hypothesize how each of the following variables will affect the rate of photosynthesis. Temperature CO availability for the plant 2 4. Set the thermometer to 25°C (room temperature) and the light intensity to 20. a) What were the bubbles per minute at this setting? _________ bpm b) Now increase the CO2 available to the elodea. What were your bubbles per minute? __________ bpm c) Based on your data, how does the amount of available CO affect the rate of photosynthesis? 2 5. Keep your settings from 4 (25°C, light intensity of 20, increased CO2 ). a) What were the bubbles per minute at this setting? _________ bpm b) Now increase the temperature to 40°C. What were your bubbles per minute? _________ bpm c) Based on your data, how does an increase in temperature affect the rate of photosynthesis? 6. Return to your settings from 4 (25°C, light intensity of 20, increased CO2 ). a) What were the bubbles per minute at this setting? _________ bpm b) Now decrease the temperature to 10°C. What were your bubbles per minute? _________ bpm c) Based on your data, how does a decrease in temperature affect the rate of photosynthesis? 7. Alter the variables in order to determine which combination leads to the highest rate of photosynthesis. Which combination of settings produced the highest number of bubbles per minute? a. Temperature: ___________ b. Light: ____________ c. CO : ____________ 2 8. Based on your data, explain how light intensity affects the rate of photosynthesis.
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