Photosynthesis & Cellular Respiration Lab

Photosynthesis & Cellular Respiration Lab5th Grade PSITeacher’s Notes:Teacher Background:Cellular respiration occurs in both animals and plants. It’s a common misconception thatonly animals have cellular respiration but both plants and animals use this process toconvert sugar into energy for cells. This means that both plants and animals need anduse oxygen (see reaction below). Photosynthesis and cellular respiration are in acontinual cycle. In this lab, we use our breath to model the waste product (CO2) fromcellular respiration in animals, while this occurs naturally amongst animals and plants.Time:This lab is designed to be split into two parts. Part 1 will take approximately 30 minutesand Part 2 will take approximately 35 minutes. Plan to allow at least one hour inbetween Part I and Part 2.Materials:Whole Class DropperBromothymol Blue (BTB) IndicatorPhotosynthesis-CellularRespiration Cycle illustration fromnotes Science notebookIndividual Cellular Respiration RecordingSheetProcedure:Part 11. Students will be conducting experiments to discover if there is a relationshipbetween photosynthesis and cellular respiration.2. Make sure they have all the necessary materials and supplies prior to beginningthe experiments. Instruct them to follow along with your demonstrations of steps3. Model each step below and have students complete each step before moving onto the next. Explain that students will complete the Cellular RespirationRecording Sheets during each step of investigation.www.njctl.org5th Grade PSIEnergy in Organisms

4. Explain that students will be working with an indicator. Ask if anyone knows whatan indicator is. If not, explain that an indicator is a substance that tells if anothersubstance is present or what that substance is. The indicator used, BTB, turnsyellow in the presence of carbon dioxide (CO2) and green-blue in the presence ofoxygen (O2).5. Show students the beaker. Ask them to predict what will happen if they blow intothe beaker. Ask them to record their prediction on their Cellular RespirationRecording Sheet. Ask several students to share their ideas and explain theirreasoning. (Students may say they are blowing carbon dioxide in and it shouldturn yellow.)6. Model how to put the plastic straw into solution and blow into it. Have studentsblow into their beaker until they see a change in color (this may take a coupleminutes). Remind student to be careful not to drink the solution.7. Instruct students to record their observation on the recording sheet.8. Model how to set up the experiment: Put elodea into one of the test tubes and use the funnel to fill the tube withthe BTB solution from the beaker. Model how to fill the other test tube with only the BTB solution. Model how to seal the test tubes with caps and carefully turn them upsidedown and place them in the empty beaker.9. Guide students in designing an experiment to observe cellular respiration.Instruct students to draw and label their set up on their recording sheet alongwith their hypothesis on their recording sheet.10. Ask several groups to share their hypotheses. Discuss their ideas. Instructgroups to put the beaker containing the two test tubes in the sunlight for at leastan hour or until the next day.Part 21. After at least one hour in the sunlight instruct students to observe the test tubesand record their observations on the recording sheet. Ask several groups toshare what they observed in both test tubes.2. Ask the table groups to use what they know about photosynthesis to discusshow/why the color changed (or not). Have students write their own answers ontheir handouts.a. BTB is an indicator. It changes color when carbon dioxide is present. It willturn yellow when carbon dioxide is present and green when carbondioxide is in the process of being removed.b. Expected Responseswww.njctl.org5th Grade PSIEnergy in Organisms

Cause4.5.6.7.ExplanationExhale carbon dioxideby blowing into strawPhotosynthesis takesElodea Solution Solution turns fromplace converting the CO2Sunlightyellow - green - blueto O2This test tube has noSolution SunlightStays yellowplant, CO2 is notconverted.c. Teacher Note: Through questioning make sure students understand thatphotosynthesis took place when the elodea was put into the sunlight,which allowed the elodea to remove the carbon dioxide from the solutiontherefore turning it back to blue.Ask table groups to discuss what they think would happen to the water with theElodea if a snail was added into the test tube. If needed, prompt students withthe idea that the snail is an animal—what would it contribute that the plant mightneed?a. Teacher Note: the snail would breathe into the water, causing the water toturn yellow; but the plant would be photosynthesizing, releasing oxygen,so the water would actually stay a bluish colorAsk students to recall the equation for photosynthesis, first in words, then usingthe chemical formulas.Write the word cellular respiration and photosynthesis equations on the board.Ask students which side of the equation would represent the snail? Which wouldrepresent the plant? Through questions, help students to see that cellularrespiration is the opposite reaction to photosynthesis.Facilitate a discussion about the results of the experiment prior to instructingstudent to complete questions 7 through 11 on the recording sheet.Carbon Dioxide3.Indicator changewww.njctl.orgSolution turns yellow5th Grade PSIEnergy in Organisms

Photosynthesis & Cellular Respiration Lab Name:5th Grade PSIExperimental Question:What is photosynthesis? What is cellular respiration?How do plants gather and convert energy into food?Purpose:What is the process that plant go through to create energy? How do we consume andprocess that energy? Plants use photosynthesis to make food and release oxygen andplants and animals use cellular respiration to break down food (sugars) and releasecarbon dioxide. Photosynthesis and cellular respiration are reverse processes. Duringthis lab you will investigate the processes of photosynthesis and cellular respiration.Materials:Per group or table groups Safety goggles2 - 250mL beakers (or clear cups)WaterPlastic straw Elodea or similar plant2 Test tubes with capsFunnelTrayAccess Prior KnowledgeComplete the Photosynthesis/Cellular Respiration T chart with everything you knowabout each item. Share out your thoughts with the class.Photosynthesiswww.njctl.orgCellular Respiration5th Grade PSIEnergy in Organisms

Procedure:Part 11. You will be conducting experiments to discover if there is a relationship betweenphotosynthesis and cellular respiration.2. Make sure you have all the necessary materials and supplies prior to beginningthe experiments. Follow along with your teachers demonstrations of steps. Donot move on until instructed to do so.3. Wear on safety goggles for each step of the experiment. In this experiment youwill be using an indicator called BTB. This indicator turns yellow in the presenceof carbon dioxide (CO2) and green-blue in the presence of oxygen (O2).4. Predict what will happen when you blow into the beaker. Record your predictionon the Cellular Respiration Recording Sheet.5. Pour the directed amount of indicator into a beaker. Place a straw into thebeaker and slowly exhale through the straw into the indicator. Be careful to notdrink or inhale the solution.6. Record you observation on their Cellular Respiration Recording Sheet.7. Design an experiment using the supplied materials to test and observe cellularrespiration. Draw and label the set up the Cellular Respiration Recording Sheet.8. Within your groups discuss what you think will happen in this experiment anddevelop your ideas to form a hypothesis. Record your hypothesis on the CellularRespiration Recording Sheet.9. Place your beakers containing the test tubes in the sunlight for at least two hoursor until the next day.Part 21. After at least one hour in the sunlight observe the test tubes and record yourobservations on the recording sheet.2. Discuss what is missing from the test tube that the Elodea needed. Answerquestions 8 on the recording sheet.3. Review the chart you created at the beginning of the lesson. Using what youknew and have learned about cellular respiration complete the Venn Diagram onthe recording sheet.4. Compete review questions 10 & 11 on the recording sheet.www.njctl.org5th Grade PSIEnergy in Organisms

Cellular Respiration Recording Sheet Name:5th Grade PSIPhotosynthesis Cellular Respiration Record Sheet1. Original color of BTB solution:2. Prediction: What will happen when carbon dioxide (CO2) is added to thesolution?3. Observation: What happened when carbon dioxide (CO2) was added to thesolution?4. Draw and label test tubesTest tube #1 (with elodea)Test tube #2 (without elodea)5. Hypothesis: If we put the test tubes into the sunbecause.www.njctl.org5th Grade PSIEnergy in Organisms

6. Draw and label test tubesTest tube #1 (with elodea)Test tube #2 (without elodea)7. Observation (after one hour in sunlight):CauseIndicator ChangeExplanationCarbon DioxideElodea solution SunlightSolution sunlightwww.njctl.org5th Grade PSIEnergy in Organisms

8. What would happen to the water with the Elodea if a snail was added into the testtube? What would it contribute that the plant might need?9. Label the let Photosynthesis and the right Cellular Respiration, in the middle writeSame, then complete the Venn Diagram:www.njctl.org5th Grade PSIEnergy in Organisms

10. Conclusion: What do you think caused the changes in color? Keep in mind thatBTB indicator reacts with carbon dioxide.11. What would happen if the elodea test tube was put in a dark closet instead ofsunlight? What color would the solution be and why?www.njctl.org5th Grade PSIEnergy in Organisms

Photosynthesis & Cellular Respiration Lab 5th Grade PSI Teacher’s Notes: Teacher Background: Cellular respiration occurs in both animals and plants. It’s a common misconception that only animals have cellular respiration but both plants and animals use this process to convert sugar into energy for cells.