LESSON PLAN

 

Name: Saba Waheed

 

Title of lesson: Properties of water

 

Date of lesson:

 

Length of lesson: 1-2 class periods.

 

Description of the class:

                     Name of course: Chemistry

                     Grade level: 9-12

                     Honors or regular:

 

Source of the lesson:

            The following websites were used in this lesson:

  1. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/HydrogenBonds.html
  2. http://www.exploratorium.edu/ronh/bubbles/sticky_water.html
  3. http://tidepool.st.usm.edu/crswr/hydrogenbond.html
  4. http://www.visionlearning.com/library/flash_viewer.php?oid=1380&mid=57
  5. http://www.visionlearning.com/library/flash_viewer.php?oid=1381&mid=57

 

TEKS addressed:

            (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;

(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;

I.      Overview

The unique properties of water are due to its structure and composition. Water molecule has two hydrogen atoms with one oxygen atom. Each Hydrogen atom makes one covalent bond with oxygen in such a way that they have an angular shape. This shape of the water molecule makes it polar due to the partial negative charge on the oxygen and partial positive charge on the hydrogen atoms. These partial charges allow water to make hydrogen bonds with other water molecules, which gives water its unique physical properties. Some of the unique physical properties of water due to hydrogen bonding include high heat capacity, high specific heat, high boiling point temperature, high surface tension, and cohesion-adhesion forces. This concept is important for the students because the students will be able to relate the use of water in their daily life to its properties.

 

 

II. Performance or learner outcomes

            Students will be able to:

Ÿ     Draw the structure of water and label the partial charges on oxygen and hydrogen.

Ÿ     List the properties of water i.e. Density, Polarity, Solubility, Boiling point, cohesion, adhesion, and thermal properties.

Ÿ     Define each property and give at least one example.

Ÿ     Apply these properties to their daily lives through activities.

 

   

III. Resources, materials and supplies needed

¯    Projector.

¯    Transparencies of the notes (attached at the end of lesson).

¯    Computer to show the simulations for the hydrogen bonding.

 

IV. Supplementary materials, handouts.

o      Notes hand out.

o      Construction paper for the evaluation part of lesson.

 

Five-E Organization

Teacher Does                    Probing Questions                    Student Does      

Engage: (5-8 mins)

 

 

Students will answer questions as a pre-assessment.

 

(I may do this as a formal pre-assessment or as a class discussion or group discussion).

 

 

      

 

 

 

 

Students will answer the following questions individually:

 

1.     What is water made of? Draw the structure of water molecule.

2.     Which is denser? liquid water or ice?

3.      How does water stop the earth from getting too cold or too hot?

4.     Write three things you learned about water from the lab.

Expected Student

Responses/Misconceptions

 

 

 

The students will be expected to answer the questions as a participation grade.

 

This will give me an opportunity to observe some of the studentÕs misconceptions.

                                                   

Explore: (10-15mins) mins)

Learning Experience(s)

 The students will now be divided into groups of three.

 

Students will relate the lab activities to the properties of water.

 

(Lab activities handout is attached at the end of lesson plan)

 

 

 

 

 

      The students will be allowed to use their books and computers as a resource to explore the reason behind the behavior of water in each of the activities they did in lab.

 

They will be asked to write at least one reason for each activity and relate to the property of water.

 

Expected Student

Responses/Misconceptions

 

Students will explore the different properties of water.

    

Explain: (15-20)

Learning Experience(s)

 

 

 The purpose of each activity will now be explained. The students will be informed how each activity is related to the different properties of water.

 

 

 

 

 

I will explain the reason for the water to be unique i.e. the concept of hydrogen bonding.

 

I will show two simulations from the following websites to help the students understand the concept of hydrogen bonding:

1.     http://www.visionlearning.com/library/flash_viewer.php?oid=1380&mid=57

 

 

2.     http://www.visionlearning.com/library/flash_viewer.php?oid=1381&mid=57

 

I will give the students the formal names for the properties of property and define each of the following property of water.

 

  1. High boiling point.
  2. High specific heat.
  3. High heat capacity.
  4. High density.
  5. High surface tension.
  6. Cohesion-adhesion forces and capillary action.

 

 

(The definitions for each of the above mentioned concept are on the lecture outline which is attached at the end of lesson).

 

Expected Student

Responses/Misconceptions

 

 

The students will take notes and listen to the explanation for the activities they just did.

 

 

                                               

Extend / Elaborate:

Learning Experience(s)

 

 The students will apply the properties of water to its use in cars which is a part of their project.     

 

They will be allowed to use the resources such computer and library to find out how water is used in cars?

 

 

 

 

The students will assigned to answer the following questions:

  1. What are the parts of cars where water is used?
  2. WhatÕs the role of water in that particular part of car?
  3. Which property of water makes it useful in that part of car?

 

* Any questions they come up will be discussed or answered individually*

 

Expected Student

Responses/Misconceptions

 

 

The students will use resources and answer the questions. This will help me to see how far the students can relate the water properties to its use in cars.

   

  Evaluate:

 

 

   Students will be asked to make a concept map for the properties of water.

 

*Each student will make their own concept map*

 

 

 

 

A sample of concept map will be displayed on the board to give them an understanding of how to make a concept map.

 

 

Expected Student

Responses/Misconceptions

 

Students will make the concept make and relate the different concepts to each other and to their daily lives.

 

 

 

Percent effort each team member contributed to this lesson plan:

100%       Name of group member   Saba Waheed.

 

¯    NOTES FOR LECTURE:

 

HYDROGEN BONDING:

 

 

A relatively weak bond formed between a hydrogen atom and oxygen with an unshared electron pair.

 

 

Molecules in water and other liquids that undergo hydrogen bonding clump together. More energy is needed to separate these particles so they have higher boiling points, heat capacity and heat of vaporization than other liquids. Water has its unique physical properties due to hydrogen bonding.

 

 

EXAMPLES:

 

POLARITY:

When the Hydrogen and Oxygen combine by the sharing of electrons, the sharing is not equal, resulting in water being polar.

Consider what happens when an adult shares a candy bar with a child. Usually the adult, being bigger, gets a bigger portion of the candy bar. So it is with water.

Oxygen, being about 32 times more massive than Hydrogen, tends to pull the shared electrons closer to it, and does not share equally with the Hydrogen. Since the Oxygen has most of the electron, it also has more of a negative charge. The Hydrogen, having a smaller portion of the electrons, loses its negativity and becomes slightly positively charged. This type of bonding causes the water molecule to be polar, or charged at its ends.

BOILING POINT:

 

THE TEMPERATURE AT WHICH THE VAPOR PRESSURE OF A LIQUID IS JUST EQUAL TO THE EXTERNAL PRESSURE ON THE LIQUID.

 

The boiling point of water is = 100¡C = 373.15 K

 

THE BOILING POINT OF WATER IS HIGHER THAN MANY OTHER LIQUIDS SUCH AS ALCOHOLS AND VINEGAR.

 

SOLUBILITY.

 

THE SOLUBILITY OF A SUBSTANCE IS THE AMOUNT OF SOLUTE DISSOLVED IN A GIVEN QUANTITY OF A SOLVENT.

 

More substances dissolve in water than in any other liquid. For this reason, water is often called the "Universal Solvent."

 

EXAMPLES:

 

  1. Water and oil are not soluble.

 

  1.  Table salt can dissolve in water because water molecules can surround the positive sodium ion or the negative chloride ion, the common components of table salt.

 

SURFACE TENSION

 

 

Surface tension is caused by the attraction between the molecules

EXAMPLES:

 

Water's high surface tension allows for the

á      formation of water droplets and waves

á      allows plants to move water (and dissolved nutrients) from their roots to their leaves

á       The movement of blood through tiny vessels in the bodies of some animals.

á      It is due to the high surface tension of water that insects can walk on the water surface.

 

 

ADHESION

 

THE QUALITY OR CONDITION OF STICKING TOGETHER OR HOLDING FAST.

 

Adhesion is attraction of water molecules to other substances.

 

For example:

 

Adhesion is seen:

When water is dropped on tissue paper, it climbs up to the tissue fibres.

 

 

 

COHESION

 

The attraction of one water molecule to another resulting from hydrogen bonding.

 

The ability of water molecules to quickly break and re-form hydrogen bonds gives it a property called cohesion.

 

EXAMPLES:

 

  1. This is why water falls from the sky as raindrops, and not individual molecules,
  2. Water tends to bead up on the hood of your freshly waxed car

 

 

 

 

 

 

 

DENSITY

 

The density of a substance (liquid, solid, or gas) is defined as the mass of that substance per unit volume.

 

 

If an object is less dense than water than it will float, and if it is denser than water it will tend to sink.

 

EXAMPLES:

 

Ice floats because it is less dense than water.

 

Oil is observed to float on water because it is less dense than water.

Same applies to floating logs, and ducks.

If ice sank, it is very likely that ice skating would never have been invented and fishes in the lakes and rivers would not be able to survive.

 

 

 

 

 

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