How Clean is the Water in Your Town?

LESSON PLAN 1

Adhesion and Cohesion

 

Name:          Thuan Dao                                                                                 

 

Title of lesson: Adhesion and Cohesion

 

Date of lesson:

 

Length of lesson: 50 Minutes

 

Description of the class:

                     Name of course: Biology

                     Grade level: 9^th

                     Honors or regular: Regular

 

Source of the lesson:

Ideas from UTeach teachers

www.nasaexplore.com

http://eduref.org/cgi-bin/printlessons.cgi/Virtual/Lessons/Science/Biology/BIO0201.html

           

TEKS addressed:

 

112.43

(c)  Knowledge and skills.

(1)  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.

(2)  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.

(9)  Science concepts. The student knows how solution chemistry is a part of everyday life. The student is expected to:

(A)  Relate the structure of water to its function as the universal solvent;

 

I.  Overview

            Water is everywhere; it is in our sink faucets, and it's in every cell of our body. Water is an unusual substance with special properties. In this investigation, the students will be able to model the structure of water and investigate some of water’s properties.

II. Performance or learner outcomes

     Students will be able to:

            1. Identify and model the structure of water.

     2. Describe some of the properties of water.

 

III.  Resources, materials and supplies needed

For the class:

         Power Point Presentation

         Paper towels

For each group:

         Pennies (4)

         Graduated cylinders (3)

         Droppers (4)

         Detergents (1 Bottle)

         Gloves (if necessary)

         Oil (1 Bottle)

For demonstration:

         Small cup of water

         Index cards

         Net from a dish washing sponge  

 

IV.  Safety Considerations

Certain materials are choking hazards for students; make sure students use scissors or other materials appropriately.

 

V.   Supplementary materials, handouts

 

 

 

 

 

Five-E Organization

 

Teacher Does                     Probing Questions                                      Student Does   

Engage: Learning Experience(s)   Time: 5 minutes	Critical questions that will establish prior knowledge and create a need to know	Expected Student Responses/Misconceptions
Teacher will fill a cup with water all the way up.  Then, he will put an index card on the top and ask the student a question.	Do you think that the index card will hold the water? Why? How?	I think it will hold the water.  I don’t think that it will hold the water.  It might hold the water because the water molecules stick to each other.
The teacher then turns the cup upside down and sees if the water falls out.  Then, he will replace the card with a net from the sponge and ask the students another question.	Will the net hold the water?	Yes/No.  It might hold the water because the property of water is adhesion and cohesion and so it will be held inside.

                                                   

Explore: Learning Experience(s)   Time: 30 minutes	Critical questions that will allow you to decide whether students understand or are able to carry out the assigned task (formative assessment).	Expected Student Responses/Misconceptions
Water covers three fourths of the surface of the earth and it is one of the simplest yet most important molecules in living systems. The unexpected observation that you saw is due to the fact that water molecules are attracted to each other like small magnets. This attraction results in turn from the structure of the water molecule and the characteristics of the atoms it contains.	Does anybody know what this property is call?	Cohesion. If no one knows that it is cohesion, teacher will not tell students as they will investigate this property in their experiment.
Each molecule of water is made up of two atoms of hydrogen connected to one atom of oxygen.  This structure gives water its unique properties. Another property of water is its ability to stick to surfaces.	Does anyone know what that property is called?   Now you will begin an exercise to investigate the two properties of water: adhesion and cohesion.	Adhesion. If no one knows that it is cohesion, teacher will not tell students as they will investigate this property in their experiment.
Each group of four students should have a material manager and he should get the materials at this point. Teacher will hand out each group a worksheet about adhesion and cohesion.

    

Explain: Learning Experience(s)   Time: 10 minutes	Critical questions that will allow you to help students clarify their understanding and introduce information related to concepts to be learned.	Expected Student Responses/Misconceptions
What we had just finished investigating are the major properties of water, cohesion, adhesion, and hydrophilicity.	Can anyone remind me what cohesion is? Adhesion is? Hydrophilicity is?	Cohesion of water is when the water sticks to each other like magnets.  Adhesion is when water sticks to other surfaces. Hydrophilicity is water loving.  Water loves other water and thus they stick to each other why they don’t stick to oil.

                                               

Extend / Elaborate: Learning Experience(s)   Time: 5 minutes   Water is hydrophilic and polar and polar molecules like other polar molecules.  Oil is hydrophobic and non polar and non polar molecules like other non polar molecules.  This idea is called “like attract like.”

Critical questions that will allow you to decide whether students can extend conceptual connections in new situations   How do you think detergents work, now that you have learned the basic properties of water? Hint: Detergents clean grease and grease come from oil.

Expected Student Responses/Misconceptions   Answers will vary based on the students’ knowledge of detergent and oil.

   

Evaluate: Lesson Objective(s) Learned (WRAP –UP at end) -> Summarize   Time:5 minutes     Formal assessment is from the worksheet and formative assessment is from the teacher circulating the classroom during the students’ investigation.

Critical questions that will allow you to decide whether students understood main lesson objectives

Expected Student Responses/Misconceptions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Name: ________________

Date: __________________

Teacher: ________________

 

Water Properties

 

Adhesion and Cohesion

 

1. Obtain a medicine dropper and a small (10 ml) graduated cylinder. Make sure the dropper is clean.
2. Fill the graduated cylinder with water; it will be your water reservoir for this investigation.
3. Now, let's see how many drops of water you can you place on the surface of a penny before it overflows.

 

	Number of Drops Predicted to Overflow the Penny	Number of Drops it Takes to Overflow the Penny
Student #1
Student #2
Student #3
Student #4
Average

 

4. How many drops were you able to place on the surface of the penny before it overflowed? __________ drops.
5. If the number of drops is very different from your prediction, explain what accounts for the difference.

 

 

 

 

 

 

6. Describe the water just before it overflows the penny in terms of adhesion and cohesion.  What are the water molecules doing?

 

 

 

 

 

 

 

7. Now, dry the penny with a paper towel and with your finger spread one small drop of detergent on the surface of a dry penny. 
8. How many drops do you think this penny will hold after being smeared with detergent, more, less, or the same as before? Why?

 

 

 

 

9. Specifically, how many drops do you think it will hold?

 

	Number of Drops Predicted to Overflow the Penny	Number of Drops it Takes to Overflow the Penny
Student #1
Student #2
Student #3
Student #4
Average

 

10. How many drops were you able to place on the penny before it overflowed this time? __________ drops.
11. Did the detergent make a difference? Describe the effect of the detergent.

 

 

 

 

 

 

 

12. What does the detergent do to have this effect on water?

 

 

 

 

 

Density, Hydrophobic, and Hydrophilic

 

1. Put 8 ml of water into a 10 ml graduated cylinder.
2. What will happen if you add cooking oil? (Predict by choosing a, b, c, d, or e below)
   a. the oil will float on top of the water
   b. the oil will sink to the bottom of the water
   c. the oil will dissolve in the water
   d. the oil will become mixed up with the water
3. Gently add 2 ml of cooking oil by tilting the cylinder of water slightly and letting the oil run slowly down the inside of the cylinder.
4. What happened?

 

 

 

5. Keep this graduated cylinder and its content and get a new one for the next experiment.
6. Place 8 ml of cooking oil in a 10 ml graduated cylinder.
7. What will happen when you add water? (Predict by choosing a, b, c, d, or e below)
   a. the water will float on top of the oil
   b. the water will sink to the bottom of the oil
   c. the water will dissolve in the oil
   d. the water will become mixed up with the oil
   e. other (what?)
8. Gently add 2 ml of water by tilting the cylinder of oil slightly and letting the water run slowly down the inside of the cylinder.
9. What happened?

 

 

 

 

 

10. Which is less dense (less weight per ml.), oil or water? ____________________

 

 

 

 

 

 

 

11. Did the oil mix with the water in both cases? Please explain.

 

 

 

 

 

 

 

12. Water is hydrophilic and oil is hydrophobic.  What do you think the effect of oil spill have on our water?

 

 

 

 

 

13. How will detergents affect the water in our town based on what you have learned about detergent and its effect on water adhesion and cohesion?