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.
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.
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.
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.
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.
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)
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.
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.
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.
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.
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
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.
Station A
Activity
1: Coin in the Cup
Station B
Activity 3: Is a Newspaper Stronger than a Board?
Station D
Activity 7: Does 3 + 3 = 5?
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.
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.
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.
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.
Air is all around us and exerts pressure.
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.
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).
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.
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).
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.
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.
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.
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.
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.