Motivational Problem Exercises
Based on
Simple Experiments
Josef Trna
Faculty of Education, Masaryk University
Brno, Czech Republic
trna@ped.muni.cz
1 Cognitive Motivation
in Science Education
• Teachers are limited in methods how to improve students’ attitude
to science education.
• There is need for innovation of educational strategies and
development of new educational technologies.
• Cognitive motivation of students, playing a crucial role in
attracting students to science, seems to be a key idea in these
processes.
• We can apply a set of cognitive motivational teaching
techniques, some of which appear to be very important:
(1) problem exercises
(2) simple experiments with everyday objects
(3) information from everyday life.
Problem Exercises
• Problem solving (Maslow 1954, Woods 1994) is an important
•
•
•
•
need for every human.
Psychological base of increasing cognitive needs is “perceptional
and conceptual conflict” (Berlyne 1977, Hrabal & Man &
Pavelkova 1989).
This conflict becomes an incentive what causes a strong motivation
in science lessons and so students becomes active which heads
towards conflict elimination and satisfaction of the need.
An induction of that conflict has several variants (Berlyne 1977):
surprise, paradox, doubt, uncertainty and difficulty.
These variants are going to be used for the creation of a set of
motivational problem exercises.
Simple Experiments
•
•
•
Simple experiments have many characteristics placing them at the top of
cognitive motivational techniques: transparency of presentation of
science phenomenon base.
This transparency is given especially by the three following factors:
(1) Reduction an extra phenomena which may occur within an
experiment.
(2) Qualitativeness of an experiment when students’ attention is not
taken away from phenomenon base to unnecessary measure.
(3) Easy realization by students who perceive an experiment with
every sense.
The significant group of simple experiments are simple experiments
with everyday objects (hands-on experiments). So the
transparency of phenomenon base observation is supported thanks to
the fact that students know these objects from their everyday life, so
their attention is not taken away from the demonstrated
experiment and they can concentrate on the demonstrated
phenomenon.
Everyday Life
• The application of information from everyday life in science education is a
•
•
source of strong cognitive motivation.
Important applications possible for using in science education are the
following:
(1) Human organism: Students are acquainted with human body
parameters which can be expressed with the aid of quantities, units and
laws. Also external conditions are important for preservation of vital
functions of the human organism including health protection against
negative extraneous influence.
(2) Home, entertainment, sports etc: Students can be motivated by
explanation of a base of commonly used domestic equipment such as
heat and light sources, means of transport, audiovisual technique,
chemical agents, domestic plants and animals, information on safe,
economical and ecological working at home and at work,
entertainment, sports etc.
According to cognitive constructivism, students’ preconceptions are
an important basis for their education. From the view of motivation,
students’ preconceptions are a source of cognitive motivation.
Result:
Combined cognitive motivational
teaching technique
is formed by
problem exercises
based on simple experiments
with everyday objects.
2 Surprise
• Students have knowledge of natural object or phenomenon gained
through their own experience and learning. This object or
phenomenon is presented in surprising problem exercise so that it
conflicts with expectation arising from students’ existing
knowledge. The contrast between students’ expectation and
presented exercise is an incentive causing students’ cognitive
motivation.
• Students then make cognitive activity, conditioned on motivation,
for elimination of this contrast by solving the surprising problem
with the aid of logical thinking, calculation, measurement,
experiment or their combination.
• The typical question of a motivated student is:
„WHY IT IS NOT POSSIBLE?”
Paper ball
We make a ball from a piece of toilet paper and put it into toilet paper
tube. The ball of shaped paper has to have the same diameter as the tube
but it must not fall out spontaneously. We hold the vertical tube with paper
ball in one hand and try to tap with the other hand palm with splayed
fingers on the top of the tube to get the ball out of the tube. But the ball
does not fall out and surprisingly crawls upwards inside the tube.
Explanation: Surprising behaviour of the ball is caused by its inertia.
Balance on a surface
We put a high block of polystyrene on the water surface in a vessel with its big
sidewall. The block in a stable position is lying on the surface. Then we sink a
load (screw, nut etc.) into the centre of a small base of the second block, same
as the first one. If we put the second block with its big sidewall down on the
water surface, it surprisingly stands up on its small base.
Explanation: Surprising behaviour of the second block is caused by lowering
of the centre of block mass thanks to the load.
3 Paradox
• Paradox is an obvious conflict with “common sense”, then with
students’ knowledge and experiences. Psychological basis of
paradoxical problem exercise is similar to the previous principle of
surprise but the motivational effect is extreme and influences all
students universally. Paradoxical phenomena and experiments
played an important role in the history of science discoveries. There
are known hydrostatics and hydrodynamics paradoxes from fluid
mechanics and paradox of twins from the relativity theory etc.
• Paradoxical problem exercises initiate conditioned cognitive
motivational activity guiding students to the removal of the
paradoxical conflict from their mind.
• The typical statement of a motivated student is:
„I DO NOT BELIEVE IT IS POSSIBLE!”
Freezing mixture
We put crushed ice into a glass and fill it up with salt. Then we stir the mixture
and after a while we measure the temperature of the liquid at the bottom of
the glass. The temperature of the liquid is deep under the freezing point of
water. It reaches up to minus twenty degrees Celsius. Paradoxically, the water
does not freeze at the temperature lower than freezing point of water.
Explanation: Very cool liquid is not water but hypothermic solution of salt
in water.
Solidity of a paper
We place a strip of soft paper over an empty glass. A coin put on this paper
strip falls into the glass because the paper strip does not hold it. If we pleat
the same paper strip, the coin does not fall in. The pleated paper strip holds
even a column of coins.
Explanation: There is needed a much greater deformational force to
deform pleated paper with vertical carriage than flat paper.
4 Doubt
• Doubt about natural laws validity appears if a phenomenon is
presented with the aid of an experiment when natural law
conditions are not fully observed. Thus a conflict in the
shape of doubt about natural law validity emerges.
• This doubt is an incentive resulted in significantly motivated
proving of natural law validity and searching for its validity
limits. Knowledge of law as well as skill of its application during
problem solving is strengthened.
• The typical question is:
„WHY IS THE LAW NOT VALID?”
Non-floating polystyrene
We fill a glass of water halfway. Then we place a small piece of polystyrene
floating on the surface. We cover the piece of polystyrene on the surface with a
second smaller glass and press it vertically on the bottom. The piece of
polystyrene almost touches the bottom and does not float on the original
surface in the bigger glass.
Explanation: This is not about invalidity of the law of solids floating since the
piece of polystyrene floats on the new lower water surface.
Boil of water
We fill a plastic syringe fully with hot water (not boiling) at a temperature lower
than 100 degrees Celsius. After filling we deck the spike and swiftly pull the
piston up. The water begins to boil again. The experiment can be repeated
several times.
Explanation: Water boils at lowered pressure at the temperature lower
than 100 degrees Celsius.
5 Uncertainty
• A student is offered several possible solutions in this problem
exercise. Thus there arises a conflict in the shape of
uncertainty by the student.
• Motivated student’s behaviour follows and results in searching for
the correct solution by choice of the offered alternatives. An
uncertainty problem exercise is based on simple experiment with
everyday objects including alternatives in solution.
• The typical question of a motivated student is:
„WHAT IS CORRECT?”
Melting ice
We fill a glass fully with lukewarm water and put an ice cube inside so that the
excess water spills. A piece of ice extends from the surface. Evaporation of
water is negligible. Ice melts after a while. What situation comes after melting?
(a) water surface level does not change and water does not spill
(b) water surface level lowers
(c) a bit of water spills
Correct solution is: (a) From Archimedes’ principle and phenomenon conditions
follows that volume of water created by melting of ice is the same as
that of water overflowed during the experiment with melting ice.
Paradoxical cylinder
We glue a coin on the base of a polystyrene cylinder. The coin has the same diameter as
the cylinder. Height of the polystyrene cylinder will be adapted so that only the coin
extends from the surface of the water. We turn the cylinder coin down and place it in the
water again. How deep will the cylinder with the coin dip?
(a) the height of an extending polystyrene is the same as the height of the coin
(b) polystyrene will not extend from the surface since the coin pulls it to the bottom
(c) the higher part of polystyrene than the coin will extend from the surface
Correct solution is: (a) This is about Archimedes’ principle application. Weight of the
cylinder does not change during turning and therefore buoyant force and volume of
the sunken part of the cylinder will be the same.
6 Difficulty
• If we assign complicated or seemingly insolvable problem
exercise, a student can be motivated to solve this exercise and so
satisfy cognitive needs and need for success. We have to be careful
in the determination of an appropriate level of difficulty in the
problem exercise.
• Problem exercise must not be too difficult not to discourage
students from solving and demotivate them. Many of these
problem exercises are based on riddles and tricks. A difficulty
problem exercise includes simple experiment with everyday objects
causing difficulty of solution.
• The typical statement of a motivated student is:
„I HAVE TO DISCOVER IT!”
Glass and coin
A coin is lying on the bottom of a glass with a smooth surface, flaring upwards.
The task is to take the coin out of the glass without touching the coin or
overturning the glass.
Solution: By whirl motion with increasing speed, we put the coin in spiral
motion upwards along the inside glass wall until the coin flies out of the glass
by centrifugal force.
Tornado in a bottle
We warm two plastic caps up in flame and connect them together on their
upper parts. Then we bore a hole through the connected caps. We screw two
plastic bottles together with the aid of the connected caps and one bottle fill
almost completely with water. The connected bottles are put in vertical position
with the full one up. Only a small amount of water passes through into the
lower bottle, the rest remains in the upper bottle thanks to underpressure. The
task is to move the water from the upper bottle into the lower one without
opening or damaging of the bottles.
Solution: We whirl water in the upper bottle by whirl motion of connected
bottles in vertical position. There arises a narrow air tunnel in rotating
water in the axis of the bottle. The air is pumped through the tunnel over
from the lower bottle into the space over the water and the air pressure begins
to become. The water begins to overflow into the lower bottle. Whirlpool
phenomenon is similar to a tornado.
Thank you!
Josef Trna
Faculty of Education, Masaryk University
Brno, Czech Republic
trna@ped.muni.cz