SKP6024: ICT in Chemistry

Assignment 5: Simulation/Modelling

using the 3E (Engage, Empower, Enhance)

teaching model.

Group members:

1. NOR AZILAWATY BT AZMI M20122001519

2. NURUL AZWA BT AHMAD NASIRUDDIN M20122001520

3. NUR SOFIA BT JAFAR M20122001487

4. NURSHUHADA BT NORDIN M20122001482

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INTRODUCTION

SURFACE TENSION:

Surface tension is caused by a strong attraction of the particles. It is formed when

the particles pull together.

.

The cohesive forces between molecules down into a liquid are shared with all

neighbouring atoms. Those on the surface have no neighbouring atoms above, and

exhibit stronger attractive forces upon their nearest neighbours on the surface. This

enhancement of the intermolecular attractive forces at the surface is called surface

tension attractive forces are between unlike molecules, they are said to be adhesive

forces. The adhesive forces between water molecules and the walls of a glass tube

are stronger than the cohesive forces lead to an upward turning meniscus at the

walls of the vessel and contribute to capillary action.

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PROPERTIES OF LIQUID

The surface tension of liquid

The difference of surface tension in water, oil, alcohol, soapy water and

mercury.

The relationship of temperature and intermolecular forces towards surface

tension.

LEARNING OUTCOMES

At the end of the lesson, students should be able to answer following question;

What is the meaning of surface tension?

What is the differences of surface tension in water, oil, soapy water, alcohol

and mercury?

What happen to the surface tension of liquid when we increase the

temperature?

What happen to surface tension of liquid when the molecules of liquid have

stronger intermolecular forces?

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CHILDREN’S MISCONCEPTION ABOUT

SURFACE TENSION

All heavy or denser objects sink when placed in water.

Tension (cohesion, adhesion) is uniform throughout a liquid.

Boats, leaves, corks, float due to surface tension (these things float due to

high buoyancy or low density)

Do the water particles at the top interact with the pin in the same way as they

do with other water particles (water particles bind differently to the pin; the pin

is unable to penetrate the surface of the water, which causes it to float)

Water is pushing up on the object

Weight determines if an object will sink or float.

Heavy objects always sink and light objects always float.

A larger heavier object will not float as well as a smaller lighter object of the

same material.

The amount of water will cause objects to float or sink better.

The water drops form together and build up.

The temperature will make a difference. Hotter water will be less than cold

because the particles move faster.

Pennies dropped into a jar full of water: shape of the glass distorts your view

so you can put more in than you think. The lip of the glass lets the water go

above the rim. The pennies are smaller than you think.

Liquids are liquids and will all mix together

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ENGAGE

Justification.

Students are given several pictures as stimulant. Then teachers will allow their student to

think and give respond from the stimulant given .They have to observe and state whatever

causing the phenomenon. In this activity, question is asked is to elicit their prior knowledge

related to surface tension. Students are better if they are able to watch video about the

actual phenomenon. Still picture can give wrong perception. From this step, teacher can see

if there is any misconception problem based on the respond given by their students.

What do you think the arrangement of molecules inside a liquid?

Ans: Water is made of tiny molecules. These water molecules are highly attracted to one another through natural forces

(hydrogen bonding and van der Waals interactions). Since the water molecules are more strongly attracted to each other than

they are to the air molecules found above the surface, the water molecules at the surface stretch out and bunch up to interact

more readily with the water molecules found underneath. This stretching and bunching of the surface molecules causes a small

"film" on the surface of the water, thus providing surface tension.

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How come the water striders walk on the surface of water? Can you explain

about the below phenomenon?

Ans: The water strider was supported by acting up force. the water strider can walk on water because they are not

heavy enough to break through the surface tension barrier. This allows for fish and other under water creatures to eat

these bugs easily.

Why does water beads of water produced on apple?

Ans: There is waxing or coating on apple skin prevent water molecule from absorbed into it.

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What happen when you mix water and oil?

Ans: As daily observation, water cannot mix with oil. Oil will float on the surface of water. We can see clear boundary

between them.

What is meniscus? Why is it meniscus of water differ from meniscus to mercury?

Water

Ans: The curve in the upper surface of a liquid close to the surface of the container or another object, caused by surface

tension. The molecules of the water attract those of the container's, causing the surface of the water to cave downwards

Surface tension will attract the water solution to the molecules of the container thus lifting it up on the edges. Mercury,

being much more dense has no such attraction because it is a liquid metal.

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Mercury

How bubbles form? What makes bubble round?

Ans: The surface tension of water provides the necessary wall tension for the formation of bubbles with water. The tendency to

minimize that wall tension pulls the bubbles into spherical shapes . When air is blown inside a bubble it is pushed outwards

in all directions. This causes bubbles to become round. Bubbles are made up of a thin film or skin of soapy water. This thin

film/skin that holds the air inside of a bubble is stretchy and when the bubble is stretched; it pulls tightly.

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EMPOWER

Justification.

In this interactive activity, students will understand the basic nature of surface tension in

liquids. The lesson involves of a discrepant event that will make students think critically

about the phenomena of surface tension and correct any misconceptions. Students will

developed their scientific skill like observing, classify and comparing the result.

Moreover, it will allow the students to build their own understanding by extending the

discrepant event to liquids of different surface tensions like soap water, oil and alcohol.

Before start the experiment, certain questions being asked. Based on prior knowledge

and experience, the scientist will make an educated guess as to the answer or outcome.

This hypothesis will guide the design and execution of an experiment.

ACTIVITY 1: Do surface tension exist?

In this activity, you will do a simple experiment to determine whether surface tension

is exist or not?

What the meaning of surface tension?

Ans: Surface tension is caused by a strong attraction of the particles. It is formed when the particles pull together.

Start your experiment using the given apparatus. Please observe the phenomena

and think about it. Related to your daily life.

By using following apparatus

1 clear plastic cup Water

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1 standard size paper clip

1 large paper clip

Start your experiment.

What do you think will happen when I place this pin horizontally in the water?

Ans: Pin can float when it is placed into the water horizontally.

What do you think will happen when I place this pin vertically in the water?

Ans: Pin sinks when it is palced into the water vertically or pushed downward.

What do you think will happen when I push on the floating pin?

Ans: The pin will sink if push on the floating pin.

Procedure.

1. Place water in one cup until it is about ¾ full.

2. Use your device to pick up a paper clip. Do this by squeezing the ends of

the device together a bit and placing them inside the paper clip. Then allow

the ends to spread apart so that the tension of the ends pushes against the

inside of the paper clip and holds it in place.

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3. Carefully lower the paper clip so that it lies flat on the surface of the water.

Slowly squeeze the device to release the paper clip.

What do you see? Why do you think a paper clip, which is denser than

water, can stay on the surface of water?

Ans: The paper clip is float on the surface of the water. This is because of something having to do with the water

molecules at the water’s surface, called   surface tension .

4. Predict if several objects will sink or float if put in a tub or beaker of water.

(Objects: wood blocks, straw, penny, paperclip, straight pin, toothpick,

needle)

Will each of these items sink or float?

Ans: Sink: wood blocks, penny and straight pin.

Float: straw, paperclip, toothpick and needle.

What causes some objects to sink and others to float? What is water made

of?

Ans: Light objects float but heavy objects will float. Water has surface tension but surface tension can’t afford the

heavy objects. So, heavy objects will sink.

You can also watch this video on

http://www.middleschoolchemistry.com/multimedia/chapter5/lesson2

Justification:

Students will discover by their own either the surface tension exist or not in different liquids.

Moreover, this activity will develop their scientific skill.

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ACTIVITY 2: Do surface tension varies on different liquid?

In this activity, you will do an experiment to observe whether surface tension varies

on different kind of liquid.

What is the difference of surface tension in water, oil, soapy water, ethanol?

Ans: The surface tension in water is stronger compare to oil, soapy water and ethanol.

Start your experiment using the given apparatus. Please observe the phenomena

and think about it. Related to your daily life.

By using following apparatus and reagents

Coins Droppers

Water oil soapy water

Start your experiment.

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How could we compare the surface tension of water with other liquids?

Ans: By doing experiments such as placing an equal number of drops of each liquid on wax paper or comparing the

number of drops that can be added to the top of a coin.

What do you think will happen when we drop the liquids to the surface of a coin?

Ans: The liquids will form a beads on the coin or the liquids will spreads out flat.

Procedure.

1. Place the coin on a paper towel.

2. Use a dropper to drops of water to the surface of coin. Count the drops until

the water overflows.

3. Repeat the procedures using different liquids; oil, ethanol and soapy water.

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Which liquid will form beads up on the surface of the coin?

Ans: Surface tension also enables water to bead ups or sometimes dome higher than the top of its container.

Which liquid can be added more drops to the coin?

Why there are different amount of liquid drops can be added on the surface

of the coin?

Ans: This cohesiveness gives water its high degree of surface tension, allows it to form a nearly spherical "bead"

when a single drop is placed on a flat, nonporous surface.In contrast, oils have few, if any, hydrogen bonds

amongst their large, organic molecules. When oil is dropped onto a flat, nonporous surface, it quickly spreads

and forms a thin layer coating considerably more surface area than would a drop of water. Rubbing alcohol, on

the other hand, is a mixture consisting of 70% isopropyl alcohol and 30% water. It does contain some hydrogen

bonds within its structure, but not nearly as many as occur in pure water. Rubbing alcohol will form a bead when

dropped onto a flat, nonporous surface, but the bead will be slightly flatter and larger in diameter than a

corresponding bead of pure water.

Justification:

Students can identify the differences of surface tension for several differences liquids

through this activity. They need to handle the activity slowly to get accurate amount of liquid

drops on the surface of coin. This will teach them to do an experiment wisely.

ACTIVITY 3: Do surface tension of a same liquid varies at different

temperature? (Heating the Needles' Bath Water)

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In this activity, you will do an experiment to observe whether surface tension varies

between cold water and hot water.

Start your experiment.

What would happen if we placed the needle slowly on the icy water?

Ans: The needle will float on the surface of water.

What do you think will happen to the needle when we heat the icy water?

Ans: The temperature of icy water will rise. Needle will sink into the water

How could we compare the surface tension of hot water and cold water?

Ans: Water will lose its surface tension as we heat the water..

Procedure.

1. the apparatus

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Hot plate Thermometer Needles

Ice-water

2. Pour about a litre of ice water into the beaker; put the beaker on top of

hot plate.

3. Place slowly the needle on surface of water. Make sure it floating. Lean

the thermometer in the water in such a way that the temperature can

readily be seen without having to move the thermometer.

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4. Turn on the heat. While watching the thermometer as to make sure the

temperature is rising. Observe the needle.

What do you expect things that might happen to the needle?

Ans: the needle will sink into the water.

Why at the needle floating we when put on the ice water at the first

place?

Ans: at cold temperature molecules of water tend to stay closer. Provide a thin film to support the needle.

Why after we heat the ice water, after some time the needle sink?

Ans: When temperature arise, the molecules tend to move slightly apart. The film previous will torn.

Justification:

In this activity, students will explore the effect of temperature on surface tension of a same liquid; water. They will observe whether the needle will sink or not eventually. Other than develop their experiment skill. They will learn to make prediction.

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ACTIVITY 4: Observation on surface tension from video.

In this activity, you will watch a few videos related to surface tension. Log on to the

given websites and answer the following question.

Floating Water

http://www.youtube.com/watch?v=u5AxlJSiEEs

1. What make the card stay at the mouth of the glass when the container is placed upside down?

Ans: Pressure

2. Why must fill the water until the water flow out?

Ans: To ensure there is no gas trapped in the glass.

3. Why the blue water doesn’t came out from the jar after removing the card?

Ans: There is due to surface tension effect.

4. Why the blue water came out from the jar after we tilt the jar?

Ans: Because the surface tension already been disturbed.

Pepper and Water Science Magic Trick

http://www.youtube.com/watch?v=2suY9h7xnKg

1. Why there is nothing happen when you put finger inside the water?

Ans: Because the water contain stronger hydrogen bond, so the finger doesn’t effect it.

2. Why the pepper move away from the finger when you dip the dish detergent into the water?

Ans: Dish detergent will break the hydrogen bond and lowered the surface tension.

3. Does pepper hate soap?

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Ans: No.

Capillary action

http://www.youtube.com/watch?v=d78OidfEqAs

1. How does the liquid immediately rise up into the capillary tube when we dip the capillary tube in a beaker of liquid?

Ans: This is because the capillarity due to properties of surface tension.

2. What are the examples of capillary action given in the video?

Ans: 1.The rise of cell sap in tree and plant. 2. The absorptional ink in blotting paper.

3. According to the video, how to prevent mosquitoes from breeding?

Ans: We can pour the oil into the water. So, it will lowered the surface tension of water. Thus, when mosquitoes

breed, the egg will sink and perish.

Paper Clip in Water

http://www.youtube.com/watch?feature=player_detailpage&v=7DZP92X_n2I

1. What do you expect to happen if we add the paper clip into the water inside

the glass?

Answer: the water will spilt out because penny displace the water.

2. What happened when we continue adding paper clip into the water inside the

glass?

Answer: actually it will longer times for water to spill out because of surface tension of water prevent the spillage.

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ENHANCE

Justification:

It teach students to give full attention during learning process. This activity will enhance their

ability to collect information from various sources. Moreover, they will know the relationship

of surface tension in their daily life. The knowledge that has been given to students will be

test with some of question regarding the topic. This step will help teacher to see whether the

lesson given by the teacher is success or not. It also help teacher to detect the level of

understanding of their student. Beside that’s, it also help student to applied the knowledge

with another situation.

The Application of Surface Tension In Daily Life

1. Thermometer

A thermometer is a device that measures the temperature of things. The name is

made up of two smaller words: "Thermo" means heat and "meter" means to

measure. You can use a thermometer to tell the temperature outside or inside your

house, inside your oven, even the temperature of your body if you're sick.

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oC

oC

Why do we use mercury as indicator inside thermometer? Why at freezing point,

mercury inside thermometer stay at 0oC and why does at boiling point, the mercury

rise to 100oC

ANS: Surface tension for mercury is very high. It does not stick to the wall of capillary tube because of surface tension. If it

stuck to the wall, the measurement of temperature would not have been correct.Capillary action is the result of adhesion and

surface tension.. The surface tension acts to hold the surface intact, so instead of just the edges moving upward, the whole

liquid surface is dragged upward. Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces

between the liquid molecules.

http://www.mathisfun.com/measure/thermometer.html

Justification:

Student can explore about thermometer and relationship between boiling point and freezing

point. This activity can build up scientific knowledge and manipulative skill among students.

Students can investigate and comparing the result between boiling point and freezing point.

2. Washing Clothes by Using Soap

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The earliest recorded evidence of the production of soap-like materials dates back to

around 2800 BC in ancient Babylon. A formula for soap consisting of water, alkali, and

cassia oil was written on a Babylonian clay tablet around 2200 BC. The Ebers papyrus

(Egypt, 1550 BC) indicates the ancient Egyptians bathed regularly and combined animal

and vegetable oils with alkaline salts to create a soap-like substance. Egyptian documents

mention a soap-like substance was used in the preparation of wool for weaving.

Why we used soap or detergent to wash our clothes?

Ans: Soap reduces the surface tension of water, which allows for water to enter deeper into clothing for a better cleaning.

Is that true washing your clothes with warm water is better than cold water? Why?

Ans:Increasing the temperature of water reduces the surface tension, whereas decreasing the temperature increases the

surface tension of water.

Justification:

Students can deduce the result when used soap in washing clothes in warm water or cold

water. This activity encourages students to curiosity towards what happened in washing

clothes in warm water and hot water. Students also can build up scientific knowledge and

manipulative skill.

3. Umbrella and Tent

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?

An umbrella or parasol (also called a brolly, parapluie, rain shade, sunshade, gamp,

bumbershoot, or umbrolly) is a canopy designed to protect against rain or sunlight.

The word parasol usually refers to an item designed to protect from the sun;

umbrella refers to a device more suited to protect from rain. Umbrella and tent is

regarded as a sunshade and as a rain protector.

Why when we used umbrella and tent, water does not absorbed and leak through

the space of umbrella and tent? Is it true? Why is that when raining, the water falls in

form of droplet?

Beading of water on umbrella and tent: Waxing changes the surface properties of your umbrella. When the rains drops fall on

your umbrella, they smoothly slide down to the ground keeping your umbrella neat and clean and untouched. Water tends to

adhere weekly to the wax and strongly to itself.

Water forms in droplets. Because water is attracted to itself, the molecules at the surface of the droplet stretch out to interact

with other water molecules. This is also the reason why water droplets are spherical.

Justification:

Students can know the uses of umbrella and tent to protect from raining and hot

weather. Students use scientific skill by observing, predicting and investigation to

know why water is not leak or absorb when used umbrella and tent.

CONCLUSION

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These activities are designed to elicit any misconception among students regarding

the topic of surface tension. Their teacher will try to alter or improved the prior

knowledge of theirs. Read and explore the multimedia tutorial about surface tension

Engage, empower and enhance learning process is used to carry out these

activities. It included hands-on and mind-on activities. Moreover, students will use

scientific skill such as observing, experimenting and predicting. At the end of lesson,

the will used the concept of surface tension by related to our daily life activities. The

teacher also can test whether their lesson is understood by all the students.

List of References:

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1. A. D. Grigoriev. P. D. Grigoriev. A. M. Dyugaev. (2010). Surface levels and their contribution to the surface tension of quantum liquids. Journal of Low Temperature Physics. 163: 131-147

2. D.Ariel. W. Aaron et al. (2001). Surface tension. Boundless. Get from https://www.boundless.com/chemistry/liquids-and-solids/liquid-properties/surface-tension/On 2 April 2013.

3. K. Jim, G. Patti, and M. B. Adam. (2013). Middle school chemistry. American Chemical Society, Chemistry for Life. Get from http://www.middleschoolchemistry.com/lessonplans/ on 1 April 2013.

4. M.Bruce. (2004). Participatory partnership: Engaging and empowering to enhance environmental management and quality of life? Social Indicators Research. 71: 123-144

5. P. Maiju. A. Susanna et al. (2009). Surface tension. Get from http://www.attension.com/surfacetension?_kk=surface%20tension%20measurement&_kt=f514b4eb-db0c-4593-94cf 8e83bdcc9742&gclid=CIKB8Kzaw7YCFRFu6wodmhkAcg on 2 April 2013

6. http://serc.carleton.edu/sp/mnstep/activities/20827.html

7. http://www.homeofbob.com/science/misconceptions/densitySurfTensi.html

8. http://io9.com/5668221/an-experiment-with-soap-water-pepper-and-surface-

tension

9. http://www.chem.purdue.edu/gchelp/liquids/tension.html

10.http://hyperphysics.phy-astr.gsu.edu/hbase/surten.html

11.http://en.wikipedia.org/wiki/Thermometer

12.http://www.ehow.com/how_does_5452223_detergen__break_surface_tension

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