University of Palermo – Physics Education
Research Group
I.C.S. “Guglielmo II”,
Monreale, Palermo, ITALY
INQUIRY BASED SCIENCE EDUCATION
DESIGNING A LOW ENERGY HOME:
STUDENTS LEARN HOW THERMAL ENERGY TRANSFERS BETWEEN SYSTEMS
Daniela Bellomonte e Laura Gambino
Conduction
IBSE character: learning cycle
Before experimenting, in a preliminary
discussion students plan investigations,
develop
hypotheses,
discriminate
alternatives and debate with peers.
After experimenting, they interpret data,
and analyze the results, compare them .
Students compare the results of their
experiments with their assumptions and
proceed in identifying and explaining
eventual any differences.
ENGAGE
Four squared plates of different materials
(aluminum,
wood,
polystyrene
and
Plexiglas) and same dimensions are sited
on a table. Students are asked to touch
them and express a sensation of hot or cold.
1. Observing ice melting in plates of different materials
Assumptions:
EXPLORE
Activity n 1.1
A set of ice cubes of almost the same
dimension and at the same temperature (i.e.,
taken from the same refrigerator) are is placed
on four squares of different materials. The
classroom is asked to arrange the plates
according to the time of ice melting.
Group A: Polystyrene – Plexiglas – wood – aluminum
EXPLAIN
Group B: Plexiglas – polystyrene – wood – aluminum
At the end of activity n 1.1 students
learned that the nature of material
influences the thermal energy transfer
between
bodies
at
different
temperatures.
Results:
The figure n. 1 shows the results.
The correct sequence is:
1. aluminum 3. Plexiglas 2. wood
4. polystyrene
FIGURE n. 1
EXPLORE
EXPLORE
Activity n 1.3
A set of ice cubes of almost the same
dimension and at the same temperature (i.e.,
taken from the same refrigerator) are placed
on three FROZEN aluminum squares of
different thickness ( 0.1 cm, 1cm and 3 cm)
Students are asked to arrange the plates
according to the time of ice melting.
Activity n 1.2
A set of ice cubes of almost the same
dimension and at the same temperature (i.e.,
taken from the same refrigerator) are placed
The same set of ice cubes is placed on three
aluminum squares of different thickness ( 0.1
cm, 1cm and 3 cm).
Students are asked to arrange the plates
according to the time of ice melting.
Assumptions:
Assumptions:
Group A: 0,1 cm – 1 cm – 3 cm
Group A: 0,1 cm – 1 cm – 3 cm
FIGURE n. 3
FIGURE n. 2
Group B: 3 cm - 1 cm - 0,1 cm
Group B: 3 cm - 1 cm - 0,1 cm
Results of activity n 1.2:
The figure n.2 shows the results.
The correct sequence is:
a. 3 cm
b. 1 cm
EXPLAIN
ELABORATE
At the end of activities n 1.2 and 1.3, students
learned that the thickness of a material influences of
thermal energy transfer between bodies at different
temperatures. In the activity n 1.2 the thickest plate
transferred a greater quantity of thermal energy. In
the activity n 1.3, when the plates are frozen, the
least thick plate transferred a greater quantity of
thermal energy.
After the described activities,
students said: “All materials
have different capacity of being
passed through by the heat,
and of cooling or heating at
different speed”.
Results activity n 1.3:
The figure n.3 shows the results.
The correct sequence is:
a. 0,1 cm
b. 1 cm
c. 3 cm
c. 0,1 cm
2. Measuring insulation properties of different materials
All students agree that the aluminum plate
is the coldest and the polystyrene plate is
the hottest.
After measuring the real temperature of
each material the different
squares,
students observe that the all plates have all
the same temperature! So students compare
the result with their assumptions and
proceed to identify and justify the
differences. You cannot trust your tactile
sensation!
Why do plates
look like having
different
temperatures?
Maybe because
the aluminum
absorbs more
warmth from
my hand than
polystyrene
EXPLORE
EXPLORE
Activity n 2.1
Four different groups of students are provided with equal polystyrene cups containing equal
quantities of hot water. The cups are covered with a squared plate of the same dimension but
of different material. The each plate has two temperature sensors on both faces, which record
the difference in temperature between the inside and the outside. In the Figures 4A and 5A are
showed two examples.
Activity n 2.2
Students are provided with two equal polystyrene cups containing equal
quantities of hot water. The cups are covered with two squared aluminum
plates of different thickness (0.1 cm and 3 cm). The each plate has a two
temperature sensors on each both faces, which records the eventual
temperature differences difference in temperature between the inside and
the outside (fig. 6A).
FIGURE n. 5A
FIGURE n. 4A
FIGURE n. 6A
FIGURE n. 6B
Results:
The graph (fig. 6B) shows the four curves of inside and outside
temperature behaviors in the aluminum plates.
P
O
EXPLAIN AND ELABORATE
FIGURE n. 5B
FIGURE n. 4B
Results:
The two graphs (see fig. 4B and 5B) show the time dependence two
curves of inside (red) and outside (blue) temperatures in the
aluminum and polystyrene plates, respectively.
Convection
Observing convection currents
The whole class analyzes the data and order the materials from the greatest
to the lowest temperature differential. They also define (on the basis of the
measurements) which material they think to be is the best conductor and
the best insulator and how the thickness influences the capacity of
conducting heat.
Thermal Radiation
Build and use home-made radiometers
Building procedure:
Cut three aluminum plates of equal surface 4x7 cm2. Paint one of them of a black gloss paint, and
another one with of a white paint and leave the last one is unpainted. Connect the back of each
plate with the tip of the surface temperature sensor. After that, we mount the three plates on
polystyrene supports.
EXPLORE
EXPLORE AND EXPLAIN
Activity
A fish tank filled with water at room
temperature is placed over two bowls
filled with hot water and ice,
respectively. Two drops of red and
blue dyes are gently posed on the
tank surfaces.
Result
The figure n.7 shows the convection
currents produced by temperature
gradients in fluids.
FIGURE n. 7
EXPLAIN AND ELABORATE
The students observe the convection currents produced by
temperature gradients in fluids and conclude that hot water is
lighter and moves toward the top, when it cools down, it
becomes heavier and moves toward the bottom.
Activity
1 The unpainted aluminum radiometer faces the halogen lamp at a distance of 25 cm from the
light source (see fig. 8).
The lamp is switched on and the radiometer is illuminated for 30 seconds, after that the lamp is
switched off and removed. The temperature of the radiometer plate is recorded as a function of
time: the students observe that it rises until a maximum value is reached and subsequently
starts a decreasing cooling trend.
2 The same experiment as before is repeated filtering the visible light incoming on the
radiometer plate (see fig 9). The students observe that an increase of the radiometer surface
temperature, even in the case of total absence of visible light, is evident.
3 The three home-made radiometers face the halogen lamp at equal distances (25 cm) from the
light source (see fig 10). The lamp is switched on and the radiometers are simultaneously
illuminated for 30 seconds, after that the lamp is switched off and removed.
Results show the black sensor reaching the higher temperature, the white sensor the lower
temperature and the unpainted aluminum sensor an intermediate temperature (see fig 11).
FIGURE n. 8
FIGURE n. 9
ELABORATE
Students learned that energy transfer can due to thermal radiation and that this can also
occur in absence of visible light. Moreover, the students have realized that the absorption of
energy depends on the color.
FIGURE n. 10
FIGURE n. 11