Taste the Rainbow! Using Skittles to explore the chemistry of photosynthesis and cellular respiration. Name: Class:

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1 Taste the Rainbow! Using Skittles to explore the chemistry of photosynthesis and cellular respiration Name: Class:

2 Background Information Plants cells and animal cells use chemical reactions to engage in photosynthesis and cellular respiration. During this lab you will be using Skittles to represent the molecules found in photosynthesis and respiration reactions. While studying these two reactions you will encounter the following molecules: CO 2 (carbon dioxide), H 2 O (water), C 6 H 12 O 6 (glucose), and O 2 (oxygen). As you know, photosynthesis is the process in which plants (also called autotrophs or producers) use water and the radiant energy of the sun to create simple sugar (glucose) as a food source with oxygen as one of the products of the reaction. Cellular respiration is the process that takes place in the cells of organisms in which chemical reactions turn sugar (glucose) that we get from food along with oxygen into adenosine triphosphate (ATP). For the purposes of this lab, we will refer to ATP as energy, you can think of it as a kind of chemical battery that allows our body to store energy and rerelease it when needed. The law of conservation of matter is a fundamental principle of science that states that matter is neither created nor destroyed, it simply changes forms. You will see that during photosynthesis and respiration that the number of atoms in the reactants (the ingredients on the left side of the formula) will equal the atoms in the products (the things that are given off after the ingredients undergo a chemical reaction, on the right side of the formula). You will also learn the molecules that make up the reactants and products for photosynthesis and respiration.

3 Directions: 1. Decide what color Skittle you are going to use to represent each kid of atom. Write the color below so you won t forget. Carbon Hydrogen Oxygen 2. Complete the chart below. Use the provided equations to write out the common names of the molecules that are found in the reactants and products. For example, if NaCl were one of the molecules in the equation, you would write out Sodium Chloride (or salt) in the blank. Refer to the background information if you forgot the common names of any of the molecules. Photosynthesis: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Respiration: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O Reactants (ingredients) Products (Given off) Photosynthesis Respiration 3. How many total carbon atoms are there in the reactants of photosynthesis? 4. How many total oxygen atoms are there in the reactants of photosynthesis? 5. How many total atoms of hydrogen are there in the reactants of photosynthesis? 6. How many total carbon atoms are there in the products of photosynthesis? 7. How many total oxygen atoms are there in the products of photosynthesis? 8. How many total atoms of hydrogen are there in the products of photosynthesis?

4 9. Place the correct color and number of Skittles you chose on all of the atoms of the reactants of photosynthesis. For example, if you chose red Skittles to represent carbon, place one red skittle for each atom of carbon on the reactants side. Arrange the Skittles in the correct order so they represent the molecules on the reactants side. Have your teacher check your model for accuracy. 10. Draw a colored picture of your Skittle representation of the photosynthesis and cellular respiration reaction (both the reactants and the products). Photosynthesis: Cellular respiration: 11.How many total carbon atoms are there in the reactants of photosynthesis? 12. How many total carbon atoms are there in the reactants of respiration? 13. How many total oxygen atoms are there in the reactants of photosynthesis? 14. How many total oxygen atoms are there in the reactants of respiration? 15. Do you notice a pattern between how many atoms are in the reactants and how many are in the products? Can you guess the significance of the pattern? 16. How many total atoms of oxygen are there in the products of photosynthesis?

5 Conclusion questions: 17. What were your observations about the photosynthesis and respiration formulas? 18. What is the law of conservation of matter? 19. How was the law of conservation of matter demonstrated in this lab? 20. Why are the products of the photosynthesis reaction necessary for life on earth? 21. BONUS: What is the relationship between the products of cellular respiration and our respiratory system?

6 Taste the Rainbow! Teacher s Key Name: Class:

7 Background Information Plants cells and animal cells use chemical reactions to engage in photosynthesis and cellular respiration. During this lab you will be using Skittles to represent the molecules found in photosynthesis and respiration reactions. While studying these two reactions you will encounter the following molecules: CO 2 (carbon dioxide), H 2 O (water), C 6 H 12 O 6 (glucose), and O 2 (oxygen). As you know, photosynthesis is the process in which plants (also called autotrophs or producers) use water and the radiant energy of the sun to create simple sugar (glucose) as a food source with oxygen as one of the products of the reaction. Cellular respiration is the process that takes place in the cells of organisms in which chemical reactions turn sugar (glucose) that we get from food along with oxygen into adenosine triphosphate (ATP). For the purposes of this lab, we will refer to ATP as energy, you can think of it as a kind of chemical battery that allows our body to store energy and rerelease it when needed. The law of conservation of matter is a fundamental principle of science that states that matter is neither created nor destroyed, it simply changes forms. You will see that during photosynthesis and respiration that the number of atoms in the reactants (the ingredients on the left side of the formula) will equal the atoms in the products (the things that are given off after the ingredients undergo a chemical reaction, on the right side of the formula). You will also learn the molecules that make up the reactants and products for photosynthesis and respiration.

8 Directions: 1. Decide what color Skittle you are going to use to represent each kid of atom. Write the color below so you won t forget. FOR THE PURPOSE OF THIS TEACHER S KEY WE WILL USE THE FOLLOWING COLORS. YOUR STUDENTS WILL MOST LIKELY CHOOSE DIFFERENT COLORS. RED represents Carbon YELLOW represents Hydrogen PURPLE represents Oxygen 2. Complete the chart below. Use the provided equations to write out the common names of the molecules that are found in the reactants and products. For example, if NaCl were one of the molecules in the equation, you would write out Sodium Chloride (or salt) in the blank. Refer to the background information if you forgot the common names of any of the molecules. Photosynthesis: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Respiration: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O Photosynthesis Reactants (ingredients) CARBON DIOXIDE, WATER Products (Given off) GLUCOSE, OXYGEN Respiration GLUCOSE, OXYGEN CARBON DIOXIDE, WATER 3. How many total carbon atoms are there in the reactants of photosynthesis? 6

9 4. How many total oxygen atoms are there in the reactants of photosynthesis? 18 MY STUDENTS OFTEN HAVE QUESTIONS ABOUT WHY THE ANSWER IS 18. STUDENTS NEED TO BE REMINDED THAT THEY NEED TO MULTIPLY THE 6 AT THE FRONT OF CO2 BY THE SUBSCRIPT 2, FOR A TOTAL OF 12. THEN THEY NEED TO ADD THE 6 OXYGEN MOLECULES IN THE WATER MOLECULE FOR A TOTAL OF 18. I USUALLY EXPLAIN THAT ANY MOLECULE WITH NO SUBSCRIPT HAS AN UNDERSTOOD ONE IN FRONT OF IT SO YOU ARE REALLY MULTIPLYING 6x1 TO GET How many total atoms of hydrogen are there in the reactants of photosynthesis? How many total carbon atoms are there in the products of photosynthesis? 6 7. How many total oxygen atoms are there in the products of photosynthesis? How many total atoms of hydrogen are there in the products of photosynthesis? Place the correct color and number of Skittles you chose on all of the atoms of the reactants of photosynthesis. For example, if you chose red Skittles to represent carbon, place one red skittle for each atom of carbon on the reactants side. Arrange the Skittles in the correct order so they represent the molecules on the reactants side. Have your teacher check your model for accuracy. OF COURSE STUDENT MODELS WILL LOOK DIFFERENT BASED ON THE COLORS THEY CHOOSE, BUT SHOULD LOOK SOMETHING LIKE THE EXAMPLE BELOW.

10 10. Draw a colored picture of your Skittle representation of the photosynthesis and cellular respiration reaction (both the reactants and the products). Photosynthesis: Cellular respiration: STUDENT ANSWERS WILL VARY, MAY LOOK LIKE THE EXAMPLE ABOVE, OR A VARIATION. I USUALLY CHECK THAT THE FORMULA AND COLORS ARE CORRECT, BEYOND THAT I SIMPLY LOOK FOR CREATIVE EFFORT. 11.How many total carbon atoms are there in the reactants of photosynthesis? How many total carbon atoms are there in the reactants of respiration? How many total oxygen atoms are there in the reactants of photosynthesis? How many total oxygen atoms are there in the reactants of respiration? Do you notice a pattern between how many atoms are in the reactants and how many are in the products? Can you guess the significance of the pattern? STUDENTS SHOULD NOTICE THAT THE ATOMS IN THE REACTANTS AND THE PRODUCTS ARE THE SAME. THE SIGNIFICANCE IS THAT THE EQUATION IS BALANCED, AND IT FOLLOWS THE RULES OF THE LAW OF CONSERVATION OF MATTER. 16. How many total atoms of oxygen are there in the products of photosynthesis? 18

11 Conclusion questions: 17. What were your observations about the photosynthesis and respiration formulas? STUDENT ANSWERS WILL VARY, BUT STUDENTS SHOULD NOTICE THAT THE ATOMS ARE REARRANGED INTO DIFFERENT MOLECULES, AND THAT NO ATOMS WERE LOST OR GAINED. 18. What is the law of conservation of matter? THE LAW OF CONSERVATION OF MATTER IS A FUNDAMENTAL PRINCIPLE OF SCIENCE THAT STATES THAT MATTER IS NEITHER CREATED OR DESTROYED, IT SIMPLY CHANGES FORMS. 19. How was the law of conservation of matter demonstrated in this lab? STUDENTS SHOULD NOTICE THAT WE DO NOT GAIN OR LOSE ANY ATOMS WE JUST REARRANGE THEM TO MAKE DIFFERENT MOLECULES. 20. Why is the photosynthesis reaction necessary for life on earth? ONE OF THE PRODUCTS OF PHOTOSYNTHESIS IS OXYGEN GAS, NECESSARY FOR HUMAN LIFE. 21. BONUS: What is the relationship between the products of cellular respiration and our respiratory system? ONE OF THE PRODUCTS OF CELLULAR RESPIRATION IS CARBON DIOXIDE GAS, A WASTE PRODUCT THAT OUR RESPIRATORY SYSTEM GETS RID OF WHEN WE EXHALE.

12 ADDITIONAL ACTIVITIES AND CLASS STARTER I USUALLY USE THIS CLASS STARTER THE DAY AFTER WE COMPLETE THE LAB, BUT IF YOU HAVE ADVANCED STUDENTS THEY MAY BENEFIT FROM DOING THIS PRIOR TO THE LAB. TEACHER KEY BELOW, STUDENT COPY ON FOLLOWING PAGE RADIANT ENERGY (SUNSHINE) RADIANT ENERGY (SUNSHINE) OXYGEN GLUCOSE CARBON DIOXIDE (SIMPLE SUGAR) CREATED WATER 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 CARBON DIOXIDE+ WATER YIELDS GLUCOSE + OXYGEN

13 THE DIAGRAM BELOW SHOWS HOW MATTER AND ENERGY INTERACT DURING THE PROCESS OF PHOTOSYNTHESIS. LIST THE WORDS OF THE SUBSTANCES THAT ARE NEEDED AS RAW MATERIALS AND PRODUCED AS PRODUCTS UNDER THE MATCHING CHEMICAL FORMULAS.

14 TEACHER NOTES: I VE FOUND THAT ONE FULL SIZED BAG OF SKITTLES PER LAB GROUP WILL USUALLY ALLOW ENOUGH COLORS TO CORRECTLY ASSEMBLE THE EQUATIONS. IF YOU WANT TO BE CERTAIN THAT YOU LL HAVE ENOUGH COLORS TO DO THE LAB CORRECTLY, YOU CAN PURCHASE ONE OF THE BIG PARTY SIZED BAGS. I USUALLY BUY ONE PARTY SIZED BAG TO USE IN THE LAB, I KEEP THESE SKITTLES SEPARATE AND USE THEM WITH ALL MY CLASSES. I ALSO BUY ENOUGH SMALL FUN SIZED BAGS OF SKITTLES FOR EACH STUDENT TO HAVE A FUN SIZED BAG AT THE CONCLUSION OF THE LAB. MAKE SURE YOU ARE FOLLOWING YOUR CAMPUS AND DISTRICT RULES REGARDING GIVING FOOD TO KIDS. I ALSO MAKE SURE TO HAVE A FEW SUGAR FREE TREATS AROUND JUST IN CASE A STUDENTS CAN T EAT SUGAR. ADDITIONAL ACTIVITIES YOU TUBE: CHANNEL: HEYSCIENCEGUYS VIDEO: PHOTOSYNTHESIS YOU TUBE: CHANNEL: MOVETODARE VIDEO: WHAT IS ATP? - BILL NYE A FREE RESOURCE BY SCHOLASTIC. SEARCH FOR VIDEO PHOTOSYNTHESIS intro.html INTRODUCTION TO CELL RESPIRATION THIS SITE DOES REQUIRE A PAID MEMBERSHIP, BUT IS REALLY WORTH IT IF YOUR DISTRICT HAS THE FUNDS. IT PAYS TO CHECK THE SITE OFEN EVEN IF YOU DON T HAVE AN ACCOUNT AS THEY ALWAYS HAVE SOME VIDEOS THAT ARE FREE TO VIEW ALL THE TIME. VIDEOS: CELLULAR RESPIRATION, PHOTOSYNTHESIS LINK WITH A GOOD PHOTOSYNTHESIS FOLDABLE ALL LINKS ARE ACTIVE AS OF THIS WRITING