Name: ___________________________________________________________________ Per. _______ Date: ____________________________ Marshmallow and Mealworm Lab: Cellular Respiration The Energy Question The Carbon Question The Movement Question Predictions - What do you think you will observe when we burn a marshmallow in a closed system? Macroscopic scale: Make predictions about what you will observe. Atomic-molecular scale: Explain your predictions using the Three Questions. Predictions about mass What do you think will gain mass? Draw labeled arrows to show how atoms or molecules might be moving into and out of the marshmallow when it is burned. Where do you think matter is moving from? Where do you think matter is going? Reactants Products What do you think will lose mass? Predictions about changes in CO2 Do you think CO2 levels will change in the closed system? If YES, how? What molecules do you think carbon atoms are a part of before the marshmallow burns? What molecules do you think carbon atoms are a part of after the marshmallow burns? Chemical Change Predictions about energy What forms of energy do you think you will observe? Where is the energy in this system before the marshmallow burns? Energy Transformation Where is the energy in this system after the marshmallow burns? Predictions – What similarities or differences will we see between the Marshmallow System and the Mealworm System? In this lab, we will be using CO2 and O2 sensors to track the amounts of those two gases in the atmospheres of our closed systems. The Movement and Carbon Questions: On the graphs below, predict what you will see if we graph our data over time. Marshmallow CO2 Concentration Over Time Marshmallow O2 Concentration Over Time Mealworm CO2 Concentration Over Time Mealworm O2 Concentration Over Time The Energy Question: What forms of energy are in a mealworm BEFORE it moves, and where is this energy? What forms are present in the system AFTER the mealworm moves, and where does the energy go? After:: Before: Energy Transformation Data Table 1 and Analysis Questions: Burning a Small Marshmallow in a Closed System Mass of Marshmallow (g) O2 (%) CO2(%) Cobalt Chloride Paper (color) Get a stamp for Data Table 1 and Analysis Questions: Initial Final 1. The burning of the marshmallow is an example of a chemical reaction. From what you have learned previously, explain what, in general, happens during chemical reactions? 2. What happened to the oxygen concentration of the air surrounding the burning marshmallow? Does this suggest oxygen is a reactant or a product? 3. What else besides the oxygen “disappeared” or could be considered a reactant? _____________________ 4. 5. What happened to the carbon dioxide concentration of the air surrounding the burning marshmallow? Does this suggest carbon dioxide is a reactant or a product? 6. What does the color change of the cobalt chloride suggest was also produced? ______________________ 7. Write the names of the two reactants and the two products for the burning of a sugar in the spaces below: ___________________ + ____________________ ___________________ + ____________________ 8. The formula for glucose is C6H12O6. Now write the chemical equation (using formulas) for the burning of sugar in the spaces below. ___________________ + ____________________ ___________________ + _____________________ Data Table 2: Mealworms in a Closed System O2 (%) CO2(%) Initial Final For all organisms to live, they must get energy from their food. The process of transforming the chemical energy in food into a form that cells can use is called cellular respiration. Like burning a marshmallow, cellular respiration is also a chemical change. While all food molecule monomers can be used for cellular respiration, let’s assume for now it is only glucose that is used in cellular respiration. Cellular respiration can be summarized using the same chemical equation that we used to represent the burning of sugar. 9. Write the word equation for cellular respiration in the spaces below: ___________________ + ____________________ ___________________ + ____________________ 10. Write the chemical equation for cellular respiration in the spaces below: ___________________ + ____________________ ___________________ + ____________________ Evidence-Based Arguments for Marshmallow and Mealworm Lab (Honors Required; Regular Optional) Fill out the table to help you figure out what evidence you now have to draw conclusions about the Three Questions in cellular respiration. Use both evidence from this lab as well as from the previous Mealworm Lab. Check yourself: Be sure that you follow the rules of matter and energy conservation. The Movement Question: Where are atoms moving when a mealworm moves? Evidence Conclusion Unanswered Questions Check Yourself Atoms last forever in combustion and living systems. All materials (solids, liquids, and gases) are made of atoms. When materials change mass, atoms are moving. When materials move, atoms are moving. The Carbon Question: What is happening to carbon atoms when a mealworm moves? Evidence Conclusion Unanswered Questions Check Yourself Carbon atoms are bound to other atoms in molecules. Atoms can be rearranged to make new molecules. The air has carbon atoms in CO2. Organic materials are made of molecules with carbon atoms: food, fuels, living and dead plants and animals. The Energy Question: What is happening to chemical energy when a mealworm moves? Evidence Conclusion Unanswered Questions Check Yourself Energy lasts forever in combustion and living systems. C-C and C-H bonds have more stored chemical energy than C-O and H-O bonds. We can observe indicators of different forms of energy: organic materials with chemical energy, light, heat energy, and motion.