Lesson #1 Final Project
Title of lesson: “pH affecting our digestive system?”
Source/
Author(s): Valerie Gibson
Target
Audience: High School Chemistry Students
Lesson plan:
I. Performance or learner outcomes
The student will be able to:
-Identify the different chemicals used in the digestive system.
-Explain the function of each part of the digestive tract.
-Explain the function of the chemicals in the digestive
tract
II. Overview Today
you (the student) will be investigating the digestive tract and how the
different pH of different foods is affected.
Make sure to write down all your observations because we will have a
class discussion at the end of the experiment.
III. Resources, materials and supplies needed
Supplies per group:
pieces of Chicken and lettuce
pH paper or pH meter
Supplies per class:
Agitator machine (1)
IV. Supplementary materials, handouts.
Lab Worksheet
V. Standards
Texas Essential Knowledge and Skills
Scientific processes. The student, for at least 40% of instructional
time, conducts field and laboratory investigations using safe, environmentally
appropriate, and ethical practices. The student is expected to:
(A) demonstrate safe practices during field and
laboratory investigations; and
(B) make wise choices in the use and conservation of resources and the
disposal or recycling of materials.
Scientific processes. The student uses scientific methods during field and
laboratory investigations. The student is expected to:
(A) plan and implement investigative procedures
including asking questions, formulating testable hypotheses, and selecting
equipment and technology;
(B) collect data and make measurements with precision;
(C) organize, analyze, evaluate, make inferences, and predict trends from
data; and
(D) communicate valid conclusions.
Science concept. The student knows that, at all levels
of nature, living systems are found within other living systems, each with its
own boundary and limits. The student is expected to:
(A) interpret the functions of systems in
organisms including circulatory, digestive, nervous, endocrine, reproductive, integumentary, skeletal, respiratory, muscular, excretory,
and immune;
(B) compare the interrelationships of organ systems to each other and to
the body as a whole; and
(C) analyze and identify characteristics of plant systems and subsystems.
Engagement
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Student behaviors / activities |
Teacher behaviors / activities |
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-Students will watch a small 5 minute video on the digestive tract
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-Show the video to the students and answer any questions before beginning the lab. |
.
Exploration
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Student behaviors / activities |
Teacher behaviors / activities |
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1) Acquire all materials needed for the experiment. 2) Take the pH of each food item with the pH paper before starting the experiment. Complete 3 trials of each: Procedure A: all natural food (no chemicals added) 1) Place a piece of the food item into the test tube. 2) Place the test tubes into the agitator on ¾ high so that the machine might impersonate the muscle contractions of the stomach. 3) Allow ten minutes, then take the test tubes out of the agitator machine 4) Test the pH of each food. Complete 3 trials of each: Procedure B: No saliva (chewing) 1) Place a piece of the food item into the test tube. 2) Add 5 mL of Hydrochloric acid (pH=1) to each test tube in order to mimic the pH level of stomach acids that also possess a pH =1. 3) Place the test tubes into the agitator on ¾ high so that the machine might impersonate the muscle contractions of the stomach. 4) Allow ten minutes, then take the test tubes out of the agitator machine 5) Test the pH of each food. Complete 3 trials of each: Procedure C: With all of the chemicals 1) Student A will chew each food item for twenty seconds, thus combing saliva with the food. (the first part of the digestive tract) 2) Student A removes the food item from his/her mouth and inserts the food item into the appropriate test tube. 3) Repeat step #3 for all of the following food item; cooked chicken and lettuce. 4) Add 5 mL of Hydrochloric acid (pH=1) to each test tube in order to mimic the pH level of stomach acids that also possess a pH =1. 5) Place the test tubes into the agitator on ¾ high so that the machine might impersonate the muscle contractions of the stomach. 6) Allow ten minutes, then take the test tubes out of the agitator machine 7) Test the pH of each food again to see of “the stomach” had any effect on the foods and how acidic the foods had become after four trials of the procedure, Questions for students to answer: - How did the chemicals affect your findings? How do you think this relates to our chemicals in our stomach? Are the chemicals needed? In your textbook, it states different “levels” of digestive, name each level and state the chemicals at that certain level and write the chemical formula for each chemical. |
Before students arrive:: 1) Teacher will put the agitator into the fume hood prior to class. 2) The teacher will put water into the agitator from a bucket. 3) Flip the switch into the “on” position, and heated the water to 36 *C (body temperature). 4) The agitator was already at 40*C, so I poured in cool water to attain a lower temperature. “What is happening to the chicken and lettuce?” Prediction: I feel the students will know that something is going to happen to the chicken and the lettuce but the students will most likely not understand why.” “Tell me the difference between a weak acid and a strong acid.” Prediction: “Do you think if we used a weak acid, would it make a difference”? Prediction: yes, but the students will most likely not be able to say why and that is what the students will discover. “How does the hydrochloric acid affect the chicken and the lettuce?” “How does the saliva affect the food?” “Do you think if we left the food in the agitator longer that would make a difference?” --Teacher will write questions on the board for the students to answer before the students turn in their lab notebook. . |
Explanation
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Student behaviors / activities |
Teacher behaviors / activities |
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-Students will make a chart for their findings -One student from each group will write their group’s findings on the board -Students will then compare with the rest of their classmates |
-Have students present their findings to the rest of the class on the chalkboard as a group. -Compare findings -Will highlight the similarities and differences between the groups with the whole class. -Use good questioning strategy to further discussion. |
Elaboration
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Student behaviors / activities |
Teacher behaviors / activities |
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Teacher will hand out a worksheet that will have the parts of the digestive system on it and the students will label where processes are occurring throughout this system. |
-Provide vocabulary words on the different parts of the digestive system |
Evaluation/Assessment
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Student behaviors / activities |
Teacher behaviors / activities |
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-Students will turn in their lab notebook to the teacher to be graded. |
-Teacher will grade students’ lab notebooks. |