OLCG: Teaching and Learning

			Teaching and Learning

OLCG SUPPLEMENTARY UNIT:

EXPLORING THE PROPERTIES OF WATER

GOALS AND OBJECTIVES:
Science Standards

Science Standard A1 — structure of matter

Science Standard A2 — physical changes in matter

Math Standards

Math Standard — Statistics and Probability 1 (levels 5-7 and 8-10) Collect, organize and display data in a variety of forms including tables and graphs

Science Process Skills

Science Standard B1 — observation, inference, prediction, collect data

Science Key Concepts

Water is the only material that exists naturally in three states — solid (ice), liquid, and gas (water vapor)

When water evaporates is changes from liquid state to gaseous state (vapor)

When water vapor cools it condenses (changes from vapor to liquid state).

Water is made up of atoms of hydrogen and oxygen forming molecules

An atom is the smallest part of an individual element that has all the properties of that element

A molecule is the smallest part of a substance that has all the properties of that substance and is composed of more than one atom

Water has adhesive and cohesive properties that influence how it behaves

Adhesion is the attraction of unlike substances on a molecular level

Cohesion is the attraction of like substances

The cohesive properties of water affect the surface tension of water molecules allowing them to do such things as mound and support certain objects heavier than water

These adhesive and cohesive properties of water may be affected by the addition of other substances

Capillary action, the movement of water up a wick, is a result of adhesion and cohesion
Cohesive properties (surface tension) of water affect its surface allowing the water to do such things as mound and support certain objects heavier than water. It is caused by attraction of the hydrogen atoms of one water molecule to the oxygen atoms of other water molecules

The adhesive and cohesive properties of water are affected by the addition of other substances.

Materials:

Small plastic medicine cups

Plastic cups

Plastic tubs

Gallon buckets

Test tubes

Eye droppers

Thread-cut into 10 inch lengths and tied into loops

Paper clips

Liquid detergent (blue Dawn)

Waxed paper

Aluminum foil

Eyedroppers (pipettes)

Rubbing alcohol

Straws

Tooth picks

Pennies

Strips of paper towel

Water soluble marking pens

Masking tape

Popsicle sticks

Rulers

Hand lenses

Plastic ziploc bags

Small plastic cups

Strapping tape

PROCEDURE:

Gear-up: Water Cycle and the States of Water

Ask students what they know about water, what it is and how it behaves (question them to determine their understanding of the states of matter and water cycle including evaporation and condensation)
Show the cup in a bag mini water cycle (held at a 45 degree angle) and ask students for their predictions about what they think will happen if you place the bag in the sunshine for a few days
Record their predictions

Explore:

Have students create their own mini water cycles, taping cup in lower corner to keep it upright, label them with their names, and tape them in the window at a 45 degree angle
Have students record on page 1 of their journals what the bag looks like at that time (start of the experiment)
Observe bags again in 2 hours and record observations in the journal
Observe and record for day 2 and day 4.

Generalize

After each observation and recording session ask students to share their observations
Give students an opportunity if necessary to go back and add to their journals

Gear Up: Drops on a Penny

Pass out a worksheet, penny, and eye dropper to each student
Show students a penny and ask them how many drops of water they think could fit on a penny before it will overflow and what shape the water will take
Have students record their predictions on the worksheet

Explore: Drops on a Penny

Give each student a penny and an eye dropper
YOUNGER STUDENTS: Have students CAREFULLY add drops to the top of the penny keeping the eye dropper straight up and down
OLDER STUDENTS: Ask student what should be done to make comparison fair, so that one person’s number can be compared to another’s (list variables to be controlled such as angle of eye dropper, temperature of water, same water, etc.)
Have students drop water on penny
Count the drops used
Observe what happens and record on the worksheet
Repeat the process two more times
Entering data onto the bar graph on board
OLDER STUDENTS: Find the average of their three trials and enter this into the table on a chart or the board
YOUNGER STUDENTS: May want to do one attempt for practice, then on for the test. They can take the highest number of the two
Draw the shape of the water from the side

Generalize:

Have each team share their observations, predictions, and results. Be sure to discuss the shape of the mound
Ask students to record their inferences on the worksheet about why they observed what they did (why do they think that they were able to get so many drops on their pennies/why do they think the water was the shape it was)
Ask if everyone got the same results (refer to graph)
Discuss why they think this might be (see how many variables they can list that could have caused the different numbers)

Explore: Surface tension with a paper clip

Have students pick up a tub of water and a paper clip for each team
Have them work together to see if they can lay a paper clip on the surface of a tub of water
After they have had time to explore themselves demonstrate how to do it if they have not figured out a method
Ask them to observe very carefully what the paper clip looks like on the water and record this on the worksheet

Generalize:

Ask students to share their strategies and observations
Ask students what their ideas (inferences) are about why they think the water could support the paper clip

Gear up — Surface tension - soap with the paper clip

Ask students to predict what they think will happen if they add 5 drops of soap to the cup with the paper clip floating on the surface
Discuss why they think so
Have them record their predictions on the worksheet

Explore:

Have each team use an eyedropper to add 5 drops of liquid detergent to their cup of water on which the paper clip is still floating
Observe what happens
Record on worksheet

Generalize:

Ask students to share their observations
Ask them to make an inference about why the paper clip behaved as it did

OLDER STUDENTS — WATER MOLECULE SIMULATION:

Have some of the students link arms to be water molecules and have others be paper clips that are supported by the water
Show the overhead transparency: Hydrogen Bonding
Tell students that what the water is doing is called "hydrogen bonding"
Ask other students to be soap molecules and show you what they think happened when the soap molecules were added
Start the "Properties of water" chart. Be sure understandings that are written have been agreed to by all students

Gear Up — Surface tension - soap with the string:

Ask students to keep in mind what they have already found out about water and predict what they think will happen to the string if they add a drop of soap inside the center of the circle of string laying on the water surface
Record predictions on worksheet
Next have them predict what will happen if they put a drop of liquid detergent outside the loop
Record your predictions on your worksheet

Explore:

Have each team of students get a tub of water, thread or light string, and a small cup of soap and eyedropper
Have students carefully lay a 10-inch loop of string on the surface of the water so that it forms a circle (Be sure they lay it carefully so that it continues to float)
One member of the team should then place a few drops of detergent INSIDE the loop.
Observe and record observations by drawing BEFORE and AFTER pictures on worksheets
Repeat if necessary for students to clearly see what happened
Dump out the water and CAREFULLY clean tubs to remove all traces of detergent
Fill the tub with new clean water
Get a new loop of thread and place it on the water in an open circle
Now have one member of the team put one or two drops of detergent OUTSIDE the loop
Observe and record observations again with BEFORE and AFTER pictures on worksheets
Repeat if necessary so that students can see clearly what happened

Generalize- Hydrogen bonding

Ask students to share their observations
Ask them for their inferences about why the string did what it did (OLDER STUDENTS: Try to develop the idea of hydrogen bonding and surface tension)

Gear Up: Adhesion and Surfaces

Ask students if they think water will behave the same on all surfaces
Discuss. Ask them to explain their ideas
Divide the class into small groups of 3-4 students. Have each student get the following supplies:
Piece of waxed paper
Piece of aluminum foil
Straw
Toothpick
Cup of water with eyedropper
Cup of rubbing alcohol with eyedropper
Small cup of detergent with eyedropper

WARN THEM NOT TO MIX UP EYEDROPPERS

Explore

Have students use the eyedropper and put 5 separate drops of water on the waxed paper
Play with the water drops using straw and toothpick
Observe and record observations on worksheet. Add a drop of detergent to the water drops and observe what happens
Record observations on worksheet
Add a drop of alcohol to the water drops and observe what happens
Record what happens
Put 5 drops on water on the piece of aluminum foil
Play with it using straw and toothpick
Observe and record observations on worksheet. Add a drop of detergent to the water drops and observe what happens
Record observations on worksheet
Add a drop of alcohol to the water drops and observe what happens
Record observations on worksheet

Generalize

Ask for observations. Discuss
Add to the properties of water chart

Gear Up: Other liquids

Ask students if, based on their previous observations, they think rubbing alcohol by itself will behave the same on waxed paper and aluminum foil as the water did
Ask why they think so

Explore

Have students use the eyedropper to put 5 drops of rubbing alcohol on the waxed paper
Play with it using straw and toothpick
Observe and record observations on worksheet. Add a drop of detergent to the alcohol drops and observe what happens
Record observations on worksheet
Put 5 drops on rubbing alcohol on the piece of aluminum foil
Play with it using straw and toothpick
Observe and record observations on worksheet.
Add a drop of detergent to the alcohol drops and observe what happens
Record observations on worksheet

Generalize for Adhesion and Cohesion:

Share observations with the whole group.
How were the liquids alike? How were they different?
How were the surfaces alike? How were they different?
What are students ideas about what caused the differences
Introduce the concepts of adhesion and cohesion to students at this time

Gear Up: Capillary Action

Ask students what they think will happen if you put a strip of paper towel into cup of colored water
Discuss
Ask students for their ideas about why

Explore

Have each pair of students take strips of paper towel and a cup of colored water
Have students dip the paper towel strip into the colored water and observe what happens
Pass out hand lenses and suggest that they might want to use them to look at the paper (wet and dry) more carefully

Generalize

Ask students for their observations and ideas about why they think the water traveled upward (discuss adhesion and cohesion vs. gravity)
Ask students what they think would happen if they put a line of marking pen on the paper towel before they dipped it (demonstrate)
Show students how to tape strips of Popsicle sticks over glass of water
Suggest that they make the pen marks above the water line

Explore:

Have students explore with pens and paper
Tape interesting strips on a piece of copy paper for sharing later
Walk around as students are exploring and encourage them to use a variety of colors including black and leave them in the water long enough for the pigments to separate

Generalize:

Have students share their observations and discoveries

Ask for their ideas about what was happening with the water and the pigments
Remind them to consider what they have learned about adhesion and cohesion of water molecules (adhesion and cohesion vs. gravity again)

Final Generalize

Review property chart and add any new ideas
Ask questions to lead students to understand that many of the behaviors of water are due to the fact that it is attracted to itself (cohesion) and may be attracted (adhesion) or repelled by other materials

Assess/Apply Suggestions

Liquid Explorations Packet
Mini-water cycle Packet
Process skills checklist
Journal entry — draw and write new ideas about water, including as many specific examples as you can think of
Student individual or small group interview — tell me what you have learned about water (have water and materials there for support)
Design an invention that moves water from one place to another. Use what you have learned about adhesion and cohesion
Tell a story from the point of view of a water drop. Include as much as you can about water, especially states of matter and adhesion and cohesion.

Name _____________________

LIQUID ON A PENNY (I)

1. Predict how many drops of water you can get on the face of a penny.

__________

2. Predict the shape the water will make on the penny looking from the side.

3. Use your eyedropper to see how many drops of water you can actually get on a penny.

Be sure to hold your eyedropper vertically (straight up and down) and use the heads side of the penny.

Do three trials and find the average.

Trial 1 Trial 2 Trial 3 Average

__________ + __________ + __________ - 3 = __________

What shape did the water actually make (as seen from the side)?

What do you think is going on?

________________________________________________________

SURFACE TENSION — PAPER CLIPS ON WATER

1. Do you think you can float a paper clip on water? _____________

2. Try as many strategies as you can think of and write or draw any successful ones below.

3. Predict what you think will happen to the floating paper clip if you add a few drops of liquid soap to the water.

__________________________________________________________

4. What actually happened?

__________________________________________________________

CIRCLE OF STRING

1. Use clean bowl or tub filled with water for this test. Place a loop of dry

thread carefully on the water so that it forms a circle. Think about what you have learned about water, and then draw a picture to show your prediction of what will happen to the thread when you add a drop or two of soap to THE CENTER of the loop.

Prediction:

2. Test your prediction by adding the soap and draw a picture of what the loop actually looked like. You may also use words to help you.

Actual:

3. Clean and refill your bowl or tub with water. Place a clean, dry string loop on the water. Draw a picture to show your prediction of what will happen if you add a drop or two of soap to the water OUTSIDE the loop.

Prediction:

4. Test your prediction by adding the soap and draw what the loop actually looked like. Again, you may also use words if you want need to.

Actual:

5. Based on your observations, why do you think the thread behaved the way it did?

__________________________________________________________

ADHESION AND COHESION — WATER ON SURFACES

1. Put 5 drops of water on waxed paper. Draw the shape of a water drop on the waxed paper as if you were looking at it from the side.

2. Write two things you observed about how water behaves on waxed paper.

a. ________________________________________________________

b. ________________________________________________________

3. Add soap to the drops of water. What happens?

___________________________________________________________

4. Add alcohol to the some of the drops. What happens?

___________________________________________________________

5. What is the shape of a water drop on aluminum foil if you look at it from the side?

6. How does water behave differently on aluminum foil compared to waxed paper?

___________________________________________________________

ADHESION AND COHESION - ALCOHOL

1. What is the shape of a drop of pure rubbing alcohol on waxed paper, if you look at it from the side?

2. Write two things you observed about how alcohol behaves on waxed paper.

a. _______________________________________________________

b. _______________________________________________________

3. What is the shape of an alcohol drop on aluminum foil if you look at it from the side?

4. List 2 ways alcohol behaves differently from water on waxed paper or

aluminum foil.

a. _________________________________________________________

b. _________________________________________________________

What are your ideas about why this might be?

___________________________________________________________

Name _____________________

MINI WATER CYCLE (P)

Draw a picture of your bag and cup at the beginning.

Name ______________________

MINI WATER CYCLE

Draw a picture of your bag and cup after 2 hours.

Name _____________________

MINI WATER CYCLE

Draw a picture on Day 2.

Name _____________________

MINI WATER CYCLE

Draw a picture of your bag and cup on Day 4.

Name ______________

LIQUID ON A PENNY

1. Predict how many drops of water you can get on the face of a penny.

__________

2. Predict the shape the water will make on the penny looking from the side.

3. Use your eyedropper to see how many drops of water you can actually get on a penny. How many did you get?

________

4. What shape did the water actually make (as seen from the side)?

SURFACE TENSION — PAPER CLIPS ON WATER

1. Do you think you can float a paper clip on water?

_____________

Try as many strategies as you can think of and write or draw any successful ones below.

3. Predict what you think will happen to the floating paper clip if you add a few drops of liquid soap to the water.

__________________________________________________

4. What actually happened?

__________________________________________________________

CIRCLE OF STRING

1. Draw your prediction of what will happen to the thread when you add a drop or two of soap to THE CENTER of the loop.

Prediction:

2. Test your prediction by adding the soap and draw a picture of what the loop actually looked like.

Actual:

3. Draw a picture to show your prediction of what will happen if you add a drop or two of soap to the water OUTSIDE the loop.

Prediction:

4. Test your prediction by adding the soap and draw what the loop actually looked like.

Actual:

ADHESION AND COHESION — WATER ON SURFACES

1. Put 5 drops of water on waxed paper. Draw the shape of a water drop on the waxed paper as if you were looking at it from the side.

2. Write one thing you observed about how water behaves on waxed paper.

__________________________________________________________

3. Add soap to the drops of water. What happens? _________________________________________________

4. Add alcohol to the some of the drops. What happens?

___________________________________________________________

5. What is the shape of a water drop on aluminum foil if you look at it from the side?

6. How does water behave differently on aluminum foil compared to waxed paper?

___________________________________________________________

ADHESION AND COHESION - ALCOHOL

1. What is the shape of a drop of pure rubbing alcohol on waxed paper, if you look at it from the side?

2. Write one thing you observed about how alcohol behaves on waxed paper.

_______________________________________________________

3. What is the shape of an alcohol drop on aluminum foil if you look at it from the side?

4. List one way alcohol behaves differently from water on waxed paper or

aluminum foil.

_________________________________________________________

5. What are your ideas about why this might be?

___________________________________________________________

_____________________________________________________________________