Lesson 2 - Cut Apples

Lesson Objectives:


  • Students will conduct a reproducible experiment.
  • Students will apply knowledge of chemical reactions and reaction triggers.
  • Students will define catalysts and differentiate between positive and negative ones.
  • Students will recognize pH.
  • Students will apply knowledge of the Maillard reactions.

Read the entire lesson including the questions before you begin. You will probably want to make yourself a chart to record your observations.

You will need:

This lesson will take a couple of days to complete. First take two medium sized apples and wash them. Be sure to wash them and dry them off before you cut them. Then cut each apple and take twelve equal sized pieces. You also need to get six separate cups.

Make sure you know what is in each cup! Labels may be helpful. Now, take one slice from each of your cups and taste it. You do not have to eat the whole slice, merely take a bite from each. (You may want to rinse your mouth after tasting some of these, and that's okay.) Do not put the slice back into its cup -- be sure to discard the piece after tasting. Describe how each apple tastes with its coating, also noting how the apple feels in your mouth (is it gritty, rough, smooth, slimy, etc?). Also note how each coating melds with the natural flavor of the apple.

Do not cover or refrigerate the remaining six slices. Let the cups sit for 24 hours, and then write down what happened with each cup. Be sure to notice the color of each apple slice and any differences, how each one physically looks, how each one smells, and be sure to touch each one to see how they feel. Do not taste them. After you have recorded your observations for each, throw the apple pieces away. Use your observations from both parts of this activity to answer the questions below.

Assignment

Grading Rubric:

10: All answers are correct within the second revision of this lesson. Answers are correct, complete, and clear; all lesson requirements have been met. All answers are in complete sentences with correct grammar and spelling.

9: All answers are correct within the third revision. Answers are correct, complete, and clear; all lesson requirements have been met. All answers are in complete sentences and work is spell-checked, but may have a few grammatical errors.

8: All answers are correct after four or more revisions. Answers are correct, complete, and clear; all lesson requirements have been met. All answers are in complete sentences and work is spell-checked, but may have a few grammatical errors.

7: One or two answers are incorrect. All other answers are factually correct, complete, and clear. All lesson requirements have been met. All answers are in complete sentences and work is spell-checked, but may have a few grammatical errors.

6: Reserved for administrative use.

5: Plagiarism - purposeful or mistaken which will lower your final grade for the course (so be very careful when posting your work!); lack of effort, disrespect, or attitude (we are here to communicate with you if you don't understand something); or 9 or more errors; or lesson requirements have not been met.

Also be aware that you will have a chance to revise your work. More than 2 revisions will result in a lower grade, so read the directions carefully and make sure you meet the requirements. No lesson is complete without the approval of the instructor, and all revisions must be completed before a grade is assigned. No grade will be given for incomplete work.

Do not submit text that you have copied from sources, including websites. All of your work should be in your own words. Using copied text would be considered plagiarism. For more information, review our page on Plagiarism and Citation.

Activity

  1. Plain: How did the apple slice taste? Is this a good way to serve apples? Why or why not (include observations from your activities to explain your opinion)?
  2. What happened to the apple slice you did nothing to in 24 hours time? Write your observations.
  3. Lemon Juice: How did the apple slice taste? Is this a good way to serve apples? Why or why not (include observations from your activities to explain your opinion)?
  4. What happened to the apple slice you coated with lemon juice in 24 hours time? Write your observations.
  5. Baking Soda: How did the apple slice taste? Is this a good way to serve apples? Why or why not (include observations from your activities to explain your opinion)?
  6. What happened to the apple slice you coated with baking soda and water in 24 hours time? Write your observations.
  7. Cooking Oil: How did the apple slice taste? Is this a good way to serve apples? Why or why not (include observations from your activities to explain your opinion)?
  8. What happened to the apple slice you coated with oil in 24 hours time? Write your observations.
  9. Boiled: How did the apple slice taste? Is this a good way to serve apples? Why or why not (include observations from your activities to explain your opinion)?
  10. What happened to the apple slice you cooked in boiling water in 24 hours time? Write your observations.
  11. Covered by Water: How did the apple slice taste? Is this a good way to serve apples? Why or why not (include observations from your activities to explain your opinion)?
  12. What happened to the apple slice you covered with water in 24 hours time? Write your observations.
  13. Which two ways of serving apples here did you think were the best, and why?

Research

You will be using outside sites to research these answers, but be sure to use your own words! Cutting and pasting from another source is plagiarism and will severely dock your grade. The point of this section is to show that you understand the answers, not just to quote another site. Please paste the url(s) of the sites where you obtained your answers after the question.

  1. Why do apples turn brown? In your explanation, name at least three other fruits or vegetables where this also happens.
  2. Is the browning of these apples the same as the browning of the bread from last lesson? Explain.
  3. In Lesson 1, it was mentioned that chemical reactions could be triggered by time, a change in temperature, or a change in pH levels (among other things). What triggered the chemical reaction in this lesson?
  4. What is a catalyst?
  5. If I were to refer to a positive catalyst or a negative catalyst, what might I mean?
  6. Did any of the treatments in this lesson serve as a catalyst? If so, which?
  7. Did any of the treatments from this lesson served as a reaction inhibitor? If so, which?
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