From observations to descriptions From observations to descriptions to explanations to explanations

M.C.Capizzo, L. Lupo and R.M. Sperandeo-MineoM.C.Capizzo, L. Lupo and R.M. Sperandeo-Mineo Dipartimento di Fisica e Tecnologie Relative, Università di Palermo, ItalyDipartimento di Fisica e Tecnologie Relative, Università di Palermo, Italy

properties and behaviours of gases

OBJECTIVE:

To provide student-teachers with learning environments and computational tools that will help them to express and reflect on their concepts and ideas about phenomena and support their activities concerning exploration, experimenting and modelling

Hands-on learning through activities : experiments and software

Training connected with experimentation in classroom

Teachers by themselves have to experience the kind of learning we think they should provide to the students

Physics Models as

Explanations of phenomena:

Descriptions of phenomena:

*

The approach is developed in several The approach is developed in several phasesphases

observingobserving

analysing pupil’s spontaneous representationsanalysing pupil’s spontaneous representations

experimentingexperimenting

modellingmodelling

OBSERVING OBSERVING Motion of motesMotion of motes Heating of compressed gassesHeating of compressed gasses

Diffusion of perfume vapoursDiffusion of perfume vapours Thermal expansion of gassesThermal expansion of gasses

Boyle’s law (P Boyle’s law (P vsvs V) V) A commercial sensor of pressure is used and volume is registered by the operator.

fitting is performed using EXCEL

EXPERIMENTING (USING MBL)

EXPERIMENTING EXPERIMENTING (USING MBL)(USING MBL)

I Gay Lussac law (V I Gay Lussac law (V vsvs T) T)

Sensors of temperature and motion

are used..

Fitting is performed using Excel.Experimental data (Pasco system)

EXPERIMENTINGEXPERIMENTING (USING MBL)(USING MBL)

II Gay Lussac Law (P II Gay Lussac Law (P vsvs T) T)

Sensors of temperature and pressure

are used.

Experimental data (Pasco system)

Pupil relevant ideasPupil relevant ideas of atomic-scale models of atomic-scale models

Gas molecules maintain some macroscopic Gas molecules maintain some macroscopic properties properties ((like thermal expansion, like thermal expansion, elasticity, stiffness,…)elasticity, stiffness,…)

Gas molecules can move, on the contrary of Gas molecules can move, on the contrary of liquid and solid molecules liquid and solid molecules

Gas molecules naturally tend to go away Gas molecules naturally tend to go away each othereach other

Gas molecules are embedded in some kind Gas molecules are embedded in some kind of substance (sometime called “heat”)of substance (sometime called “heat”)

MODELLING USING MODELLING USING ““INTERACTIVE PHYSICSINTERACTIVE PHYSICS””

Introducing the pressure concept Introducing the pressure concept from a microscopic point of viewfrom a microscopic point of view

Experimenting with models

THE MODEL:

N particle (hard spheres)

M (mass) = mean mass of air molecules

vi (velocities) equal in modulo and random directions

V (volume of the container)= 10-24 m3

Video display of the Applet

Speed, number of particles and volume can be chosen by the user.

Results of simulations

Pressure vs. Volume

y = 16,05x-1,06

y = 10,05x-1,07

y = 3,98x-1,06

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4

Volume (m^3 x 10^-24)

Pre

ss

ure

(P

asca

l x10

^5)

Np = 100

Np = 250

Np = 400

Results of simulations

Computer–based learning environments can create contexts in which student-teachers can be actively engaged in their learning processes;

The different channels conveying information allow the using of different learning strategies;

A new curriculum

to process-based

from content-based

Learning by doing and by reflecting on

the procedures originating the results