The Motivational Power of Science Discrepant Events

 

Thomas R. Koballa, Jr.

Department of Science Education

University of Georgia

 

 

         An attention getting, thought-provoking approach to initiate inquiry is through the use of discrepant events.  A discrepant event puzzles the observer, causing him or her to wonder why the event occurs as it did.  These situations leave the observer at a loss to explain what has taken place.  Discrepant events influence equilibration and the self-regulatory process, according to the Piagetian theory of intellectual development.  Situations that are contrary to what a person expects cause him or her to wonder what is taking place, resulting in cognitive disequilibrium.  With proper guidance, the individual will attempt to figure out the discrepancy and search for a suitable explanation for the situation.  When a person arrives at a plausible explanation for a discrepant event, he or she will establish cognitive equilibrium at a new level.  The individual is now better equipped mentally to approach new situations that cause curiosity and puzzlement (Piaget, 1971).

         An inquiry session initiated with a discrepant event can begin with a demonstration, preceded by directions to focus students’ attention on what they are about to observe.  The discrepant event approach receives support from cognitive psychologists, because of its potential impact on learning.

This workshop focuses on the exploration of selected science discrepant events using a three-step model developed by Alfred Friedl.  The steps of Friedl’s model are:  (1) Set Up the Discrepant Event - Students are confronted with questions or problems that gain attention, increase motivation, pose question, and reveal misconceptions.  (2) Involve the Students in Solving the Discrepancy - Students engage in purposeful activity in attempting to resolve the discrepancy.  (3) Resolve the Questions Posed by the Events and Relate Them to Body of Science Knowledge - Students will resolve the event themselves or with teacher assistance.  By experiencing science discrepant events using this model, students will sharpen their skills of observing, predicting, gathering data, and experimenting.  They will then be ready for further study of the science concept targeted by the discrepant event.

 

Sample Discrepant Events

         Science teachers have used the discrepant events presented below for decade.    The descriptions of the events are from Teaching Science to Children: An Integrated Approach by Alfred Friedl (1986).  When used to introduce science concepts, these discrepant events are best presented as teacher demonstrations.  Appropriate safety precautions should be taken when performing any science discrepant event.

 

Station A: Inertia—The First Law of Motion

The first law of motion states that an object at rest tends to remain at rest and an object in motion tends to stay in motion.

 

Activity 1: Coin in the Cup 

Place a note card on top of a glass of water, and place a coin on top of the note card.  Without touching the coin or tilting the cup, try to get the coin into the cup.

 

Investigation: (1) Try different ways of moving the card to accomplish the task; (2) Study the action of the coin when the card is quickly moved; and (3) Think about the effect of inertia on the coin.

 

Explanation: The coin remains at rest if the card is pulled quickly.  You can snap the card out with your finger.  The card will move fast, and the coin will stay at rest.  When the card is removed, the coin will drop into the cup.

 

Activity 2: Antigravity Bucket

Pour about an inch of water into a bucket.  Then swing the bucket in a large upright circle with your arm.  Does the water pour out or stay in the bucket?

 

Investigation: (1) Observe that the water remains in the bucket when it is swung overhead; (2) If performed outdoors, determine what speed the water begins to fall from the bucket; (3) Infer a relationship between the swinging speed and the tendency for the water to stay in the bucket.

 

Explanation: The swinging bucket puts the water in motion.  Once in motion, the water tends to keep moving in a straight line.  With the bucket moving in a circle, the water pushes against the bottom of the bucket as it attempts to stay in a straight line.  The push is sufficient to overcome the force of gravity. 

 

 

Station 2: Air Pressure

Air is all around us and exerts pressure.

 

Activity 3: Is a Newspaper Stronger than a Board?

Lay a thin board on a table so that one end extends over the edge by 15 to 30 centimeter.  Place a sheet of newspaper over the portion of the board on the table.  What will happen when you slowly push down on the end of the board extending beyond the table?  When you hit the extending part of the board with a sharp blow?

 

Investigation: (1) When you push down on the end of the board, predict that the board will lift the newspaper; (2) See that the board is broken when hit sharply; (3) Infer that some form of pressure is exerted when the board is hit hard; (4) Develop a theory to explain what holds down the newspaper.

 

Explanation: When the end of the board is hit, air pressure pushes down on the newspaper with such force that the board is broken.  If the board is pushed down slowly, air can get under the newspaper from the sides to equalize the pressure, and the paper is easily lifted.

 

Activity 4: Stop the Leak

Put a nail hole in the top and in the bottom of a plastic bottle.  Fill the bottle with water and seal the lid.  The water will run out of the bottle.  How can you stop the flow of water with your finger without getting it wet?

 

Investigation: (1) Observe that the water will stop flowing when the top opening is closed; (2) Infer that a force acts to hold the water in when the top opening is closed.

 

Explanation: Air enters the top hole, when water runs out the bottom hole.  When the top hole is sealed, the air pressure inside the bottle is less than outside.  Therefore, greater air pressure is exerted against the bottom hole from the outside than exerted from inside the bottle.  The difference in air pressure causes the water to stop running.

 

Station C: Adhesion and Cohesion

Adhesion is the attraction between unlike objects.  Cohesion is the attraction of like molecules for each other.  There are differences in the cohesive forces of solids, liquids, and gases.  Water is affected by both adhesion and cohesion.  Water is attracted to many substances (adhesion), and there is also an attraction among water molecules for each other (cohesion)

 

Activity 5: Cork in the Middle

Place a small cork in the middle of a partly filled glass of water.  What happens to the cork?  Try to make the cork stay in the middle.

 

Investigation: (1) Observe that the cork moves to the side of the glass even when the cork is placed in the middle; (2) Observe that the water level in the middle of the glass is slightly lower than the water touching the side of the glass; (3) Try to keep the cork in the middle.

 

Explanation: This activity shows the force of adhesion.  The water is curved upward where it touches the glass because of adhesion.  The cork floats to the highest point in the water.  The highest point is around the edge where the water touches the glass.

 

Activity 6: Join the Water

Punch several holes close together at the bottom of a plastic bottle and fill it with water.

 

Investigation: (1) Observe how the water comes out of the holes; (2) Try to make the water streams join together to form a single stream.

 

 Explanation: This activity shows the cohesive forces within water.  The water will flow from the holes in separate streams until you use your finger to pull the streams together.  Once joined, the streams tend to stay together.

 

Station D: Molecular Motion and States of Matter

         Matter is composed of atoms, and atoms are mostly space.  This is true for water and for substances with greater density like iron and stone.  Just about all matter on earth exists in one of three phases:  solid, liquid or gas.  All common gases, including oxygen, hydrogen, and carbon dioxide, are invisible.

 

Activity 7: Does 3 + 3 = 5?

Pour 50 milliliters of alcohol into a graduated cylinder.  Then, pour 50 milliliters of water into the same graduated cylinder.  Read the level of liquid in the graduated cylinder at its lowest point in the meniscus.

 

Investigation: (1) Identify the liquids as alcohol and water; (2) Observe traces of liquid inside the contains first holding the liquids; (3) Recognize that the traces of liquid could not account for the loss in volume;  (4) Observe when two volumes of water (and alcohol) are poured together there is no loss of volume; (3) Infer that the loss of volume is due to space between water and alcohol molecules.

 

Explanation: When 50 milliliters of water are added to 50 milliliters of alcohol, the volume of the two mixed together is only about 96 or 97 milliliters.  When mixed together, the combined molecules fit together better than when they are alone, so they take up less space.

 

Activity 8: What Put Out the Fire?

Place a small candle inside a beaker and add a small amount of baking soda and water.  The light the candle and pour a small amount (about 10 mL) of vinegar into the beaker, being careful not to touch the candle flame.  Why does the flame go out when you pour liquid into the beaker?

 

Investigation: (1) Observe foaming action when the vinegar touches the baking soda.  (2) Infer that a substance is produced by the foaming action that causes the flame to go out.

 

Explanation:  This activity shows the existence of an invisible substance that put out the fire.  When vinegar is poured into the dissolved baking soda, carbon dioxide is released.  The carbon dioxide fills the beaker, pushing out the oxygen and extinguishing the flame. 

 

Bibliography

Chiappetta, E. L., & Koballa, T. R.  (2002).  Science instruction in the middle and secondary schools.  Upper Saddle River, NJ: Merrill/Prentice Hall.

Friedl, A. E.  (1986).  Teaching science to children:  An integrated approach.  New York: Random House

Piaget, J.  (1971).  Biology and knowledge.  Chicago: University of Chicago Press.

 


 

 

 

 

 

 

The Motivational Power of Science Discrepant Events

 

Thomas R. Koballa, Jr.

Professor and Head

Department of Science Education

University of Georgia

 

 


 

Discrepant Event Teaching Model

 

(1) Set Up the Discrepant Event

Students are confronted with questions or problems that gain attention, increase motivation, pose question, and reveal misconceptions. 

 

(2) Involve the Students in Solving the Discrepancy

Students engage in purposeful activity in attempting to resolve the discrepancy. 

 

(3) Resolve the Questions Posed by the Event and Relate Them to Body of Science Knowledge

Students will resolve the event themselves or with teacher assistance.

 


 

 

Your Task

 

Organize yourselves into working groups of 2 to 3 persons.

 

Each group should:

 

1. Go to one of the four stations  (A, B, C or D) and select an activity.

 

2.  Learn about the activity your group has selected.  The text and photographs should help you to learn how to teach the activity.

 

3.  Teach the activity to the other group at your station.  The other group should play the role of students. 

 

4.  After teaching  the activity, clean the materials and put them away.

 

We will rotate through as many stations as time permits.  Text and photographs will be provided on-line.

 

 


 

Activities

Station A

Activity 1: Coin in the Cup 

 

Activity 2: Antigravity Bucket

 

Station B

Activity 3: Is a Newspaper Stronger than a Board?

 

Activity 4: Stop the Leak

 

Station C

Activity 5: Cork in the Middle

 

Activity 6: Join the Water

 

Station D

Activity 7: Does 3 + 3 = 5?

 

Activity 8: What Put Out the Fire?

 


 

 

Station A: Inertia—The First Law of Motion

The first law of motion states that an object at rest tends to remain at rest and an object in motion tends to stay in motion.

 

Activity 1: Coin in the Cup 

Place a note card on top of a glass of water, and place a coin on top of the note card.  Without touching the coin or tilting the cup, try to get the coin into the cup.

 

Investigation: (1) Try different ways of moving the card to accomplish the task; (2) Study the action of the coin when the card is quickly moved; and (3) Think about the effect of inertia on the coin.

 

Explanation: The coin remains at rest if the card is pulled quickly.  You can snap the card out with your finger.  The card will move fast, and the coin will stay at rest.  When the card is removed, the coin will drop into the cup.

 


 

Station A: Inertia—The First Law of Motion

The first law of motion states that an object at rest tends to remain at rest and an object in motion tends to stay in motion.

 

Activity 2: Antigravity Bucket

Pour about an inch of water into a bucket.  Then swing the bucket in a large upright circle.  Does the water pour out or stay in the bucket?

 

Investigation: (1) Observe that the water remains in the bucket when it is swung overhead; (2) If performed outdoors, determine what speed the water begins to fall from the bucket; (3) Infer a relationship between the swinging speed and the tendency for the water to stay in the bucket.

 

Explanation: The swinging bucket puts the water in motion.  Once in motion, the water tends to keep moving in a straight line.  With the bucket moving in a circle, the water pushes against the bottom of the bucket as it attempts to stay in a straight line.  The push is sufficient to overcome the force of gravity. 

 


 

Station B: Air Pressure

Air is all around us and exerts pressure.

 

Activity 3: Is a Newspaper Stronger than a Board?

Lay a thin board on a table so that one end extends over the edge by 15 to 30 centimeter.  Place a sheet of newspaper over the portion of the board on the table.  What will happen when you slowly push down on the end of the board extending beyond the table?  When you hit the extending part of the board with a sharp blow?

 

Investigation: (1) When you push down on the end of the board, predict that the board will lift the newspaper; (2) See that the board is broken when hit sharply; (3) Infer that some form of pressure is exerted when the board is hit hard; (4) Develop a theory to explain what holds down the newspaper.

 

Explanation: When the end of the board is hit, air pressure pushes down on the newspaper with such force that the board is broken.  If the board is pushed down slowly, air can get under the newspaper from the sides to equalize the pressure, and the paper is easily lifted.

 


 

Station B: Air Pressure

Air is all around us and exerts pressure.

 

Activity 4: Stop the Leak

Put a nail hole in the top and in the bottom of a plastic bottle.  Fill the bottle with water and seal the lid.  The water will run out of the bottle.  How can you stop the flow of water with your finger without getting it wet?

 

Investigation: (1) Observe that the water will stop flowing when the top opening is closed; (2) Infer that a force acts to hold the water in when the top opening is closed.

 

Explanation: Air enters the top hole, when water runs out the bottom hole.  When the top hole is sealed, the air pressure inside the bottle is less than outside.  Therefore, greater air pressure is exerted against the bottom hole from the outside than exerted from inside the bottle.  The difference in air pressure causes the water to stop running.


 

Station C: Adhesion and Cohesion

Adhesion is the attraction between unlike objects.  Cohesion is the attraction of like molecules for each other.  There are differences in the cohesive forces of solids, liquids, and gases.  Water is affected by both adhesion and cohesion.  Water is attracted to many substances (adhesion), and there is also an attraction among water molecules for each other (cohesion).

 

Activity 5: Cork in the Middle

Place a small cork in the middle of a partly filled glass of water.  What happens to the cork?  Try to make the cork stay in the middle.

 

Investigation: (1) Observe that the cork moves to the side of the glass even when the cork is placed in the middle; (2) Observe that the water level in the middle of the glass is slightly lower than the water touching the side of the glass; (3) Try to keep the cork in the middle.

 

Explanation: This activity shows the force of adhesion.  The water is curved upward where it touches the glass because of adhesion.  The cork floats to the highest point in the water.  The highest point is around the edge where the water touches the glass.


 

Station C: Adhesion and Cohesion

Adhesion is the attraction between unlike objects.  Cohesion is the attraction of like molecules for each other.  There are differences in the cohesive forces of solids, liquids, and gases.  Water is affected by both adhesion and cohesion.  Water is attracted to many substances (adhesion), and there is also an attraction among water molecules for each other (cohesion).

 

Activity 6: Join the Water

Punch several holes close together at the bottom of a plastic bottle and fill it with water.

 

Investigation: (1) Observe how the water comes out of the holes; (2) Try to make the water streams join together to form a single stream.

 

 Explanation: This activity shows the cohesive forces within water.  The water will flow from the holes in separate streams until you use your finger to pull the streams together.  Once joined, the streams tend to stay together.


 

Station D: Molecular Motion and States of Matter

         Matter is composed of atoms, and atoms are mostly space.  This is true for water and for substances with greater density like iron and stone.  Just about all matter on earth exists in one of three phases:  solid, liquid or gas.  All common gases, including oxygen, hydrogen, and carbon dioxide, are invisible.

 

Activity 7: Does 3 + 3 = 5?

Pour 50 milliliters of alcohol into a graduated cylinder.  Then, pour 50 milliliters of water into the same graduated cylinder.  Read the level of liquid in the graduated cylinder at its lowest point in the meniscus.

 

Investigation: (1) Identify the liquids as alcohol and water; (2) Observe traces of liquid inside the contains first holding the liquids; (3) Recognize that the traces of liquid could not account for the loss in volume;  (4) Observe when two volumes of water (and alcohol) are poured together there is no loss of volume; (3) Infer that the loss of volume is due to space between water and alcohol molecules.

 

Explanation: When 50 milliliters of water are added to 50 milliliters of alcohol, the volume of the two mixed together is only about 96 or 97 milliliters.  When mixed together, the combined molecules fit together better than when they are alone, so they take up less space.


 

Station D: Molecular Motion and States of Matter

         Matter is composed of atoms, and atoms are mostly space.  This is true for water and for substances with greater density like iron and stone.  Just about all matter on earth exists in one of three phases:  solid, liquid or gas.  All common gases, including oxygen, hydrogen, and carbon dioxide, are invisible.

 

Activity 8: What Put Out the Fire?

Place a small candle inside a beaker and add a small amount of baking soda and water.  The light the candle and pour a small amount (about 10 mL) of vinegar into the beaker, being careful not to touch the candle flame.  Why does the flame go out when you pour liquid into the beaker?

 

Investigation: (1) Observe foaming action when the vinegar touches the baking soda.  (2) Infer that a substance is produced by the foaming action that causes the flame to go out.

 

Explanation:  This activity shows the existence of an invisible substance that put out the fire.  When vinegar is poured into the dissolved baking soda, carbon dioxide is released.  The carbon dioxide fills the beaker, pushing out the oxygen and extinguishing the flame.