1. Introduction and Purpose Scientists wanted to find out whether chloroplasts use or produce carbon dioxide and oxygen. Carbon dioxide and oxygen are gases that are in the air around us. NEXT

2. The setup and procedure of the experiment is described in the next few slides. Pay close attention and visualize each step in the process. Make sure you understand each step the scientists did before moving on to the next slide. You will be tested to make sure you understand the procedure! NEXT

3. To find out find out whether chloroplasts use or produce carbon dioxide and oxygen, they gathered leaves from spinach plants. They used a procedure on the leaves to separate the chloroplasts from the rest of the plants. They produced 50 grams of chloroplasts in a little pile. Only chloroplasts and pieces of chloroplasts were in this pile; everything else in the plant cells from the spinach were taken away. Method NEXT

4. They put 25 grams of chloroplasts in one jar, and 25 grams of chloroplasts in a second, identical jar. They shone light on one jar, and no light on the other jar. The jars were tightly sealed so that not even air could get in or out. Method NEXT

5. Then they used small meters to measure the amount of carbon dioxide and the amount of oxygen in each jar. They measured these amounts for 5 hours after putting the chloroplasts in the jars. Method NEXT

6. Evidence 6 After reading the method of this study, four 7 th graders drew what the scientists had put in each jar. For each of the next four drawings, decide if the students were right or wrong. NEXT

7. They put 25 grams of chloroplasts in one jar, and 25 grams of chloroplasts in a second, identical jar. They shone light on one jar, and no light on the other jar. The jars were tightly sealed so that not even air could get in or out. Method NEXT

8. Then they used small meters to measure the amount of carbon dioxide and the amount of oxygen in each jar. They measured these amounts for 5 hours after putting the chloroplasts in the jars. Method NEXT

9. light 25 g of chloroplasts dark 25 g of chloroplasts YES NO Here’s the first drawing. Is this drawing correct? Drawing 1

10. They put 25 grams of chloroplasts in one jar, and 25 grams of chloroplasts in a second, identical jar. They shone light on one jar, and no light on the other jar. The jars were tightly sealed so that not even air could get in or out. Method NEXT

11. Then they used small meters to measure the amount of carbon dioxide and the amount of oxygen in each jar. They measured these amounts for 5 hours after putting the chloroplasts in the jars. Method NEXT

12. dark light 50 g of chloroplasts YES NO Here’s the second drawing. Is this drawing correct? Drawing 2

13. They put 25 grams of chloroplasts in one jar, and 25 grams of chloroplasts in a second, identical jar. They shone light on one jar, and no light on the other jar. The jars were tightly sealed so that not even air could get in or out. Method NEXT

14. Then they used small meters to measure the amount of carbon dioxide and the amount of oxygen in each jar. They measured these amounts for 5 hours after putting the chloroplasts in the jars. Method NEXT

15. Here’s the third drawing. Is this drawing correct? darklight YES NO 50 g of chloroplasts Carbon dioxide and Oxygen meter Carbon dioxide and Oxygen meter Drawing 3

16. They put 25 grams of chloroplasts in one jar, and 25 grams of chloroplasts in a second, identical jar. They shone light on one jar, and no light on the other jar. The jars were tightly sealed so that not even air could get in or out. Method NEXT

17. Then they used small meters to measure the amount of carbon dioxide and the amount of oxygen in each jar. They measured these amounts for 5 hours after putting the chloroplasts in the jars. Method NEXT

18. light 25 g of chloroplasts YES NO Here’s the fourth drawing. Is this drawing correct? dark Carbon dioxide and Oxygen meter Carbon dioxide and Oxygen meter Drawing 4

19. Correct for drawing one. Nice Job! There is something missing. You know what that is, don’t you? If not, double check the text to be sure. Click next to check the next student’s drawing. NEXT BACK

20. Try again on drawing one. There is something missing. Read the methods again to find out what is missing, and try again. BACK

21. There were 3 errors! Did you see all 3? If not go back and look for the others. Then click next. Correct for drawing two. NEXT BACK

22. There are 3 errors! Read the methods again to find out what the errors are, and try again. Try again on drawing two. BACK

23. There were 2 errors in this picture. Did you find both of them? If not go back to the text and try to find both errors. Then click next. Correct for drawing three. NEXT BACK

24. There are two errors. Go back and look at the methods and check the picture again. Try again on drawing three. BACK

25. Great Job! This picture is correct! Click next to see the results of this experiment. Correct for drawing four. NEXT BACK

26. Read the methods again then go back and look closely at the picture. Try again for drawing four. BACK

27. Results! Click next to see the results come in. Keep in mind that the molecules you see in the jars are not shown to scale. In reality they are so small that they are impossible to see with the naked eye! NEXT

28. light The jar has been in the light for 10 minutes Normal Low High Minutes Carbon Dioxide (CO2) Oxygen (O2) NEXT BACK Carbon dioxide and Oxygen meter 25 g of chloroplasts 10 2030 0

29. Normal Low High Minutes The jar has been in the light for 20 minutes NEXT BACK light Carbon dioxide and Oxygen meter Carbon Dioxide (CO2) Oxygen (O2) 25 g of chloroplasts 10 2030 0

30. Normal Low High 10 2030 Minutes The jar has been in the light for 30 minutes NEXT BACK light 25 g of chloroplasts Carbon dioxide and Oxygen meter Carbon Dioxide (CO2) Oxygen (O2) 0

31. Normal Low High Minutes Carbon Dioxide Oxygen dark 25 g of chloroplasts The jar has been in the dark for 10 minutes NEXT BACK Carbon dioxide and Oxygen meter 10 2030 0

32. Normal Low High Minutes The jar has been in the dark for 20 minutes NEXT BACK dark 25 g of chloroplasts Carbon dioxide and Oxygen meter Carbon Dioxide Oxygen 10 2030 0

33. Normal Low High Minutes The jar has been in the dark for 30 minutes NEXT BACK 25 g of chloroplasts dark Carbon dioxide and Oxygen meter Carbon Dioxide Oxygen 10 2030 0

34. What differences do you see from the data from the two jars? What do you conclude from this study? Dark Light NEXT BACK Normal Low High 20 Minutes Carbon Dioxide (CO2) Oxygen (O2) Normal Low High Minutes Carbon Dioxide (CO2) Oxygen (O2) 10 2030 0 10 30 0

35. In pairs, discuss this question and write your best answer: What do you conclude from the results of this study? Write your answer in your packet. If you would like to see the result again please click here If you would like to see all the steps of the experiment please click here. BACK