Introductory Course
On Experimental Science

Àgueda Gras-Velázquez, Undergraduate student in Physics, Universitat de València, CAT(agueda_gv@yahoo.com)

Vicent Soler-Selva, Institut d’Educació Secundària Sixto Marco, Avinguda de Santa Pola s/n, E-03202, Elx, CAT (Spain) (vicent@medtelecom.net)

Albert Gras-Martí, Dpt. of Physics, Universitat d’Alacant, Apt. 99, E-03080, Alacant, CAT (Spain) (agm@ua.es)

Assistants

Marisa Cano Villalba, Rodney Chinchilla Alberola, Anna Climent Montllor, Joaquim Gomis Soler, Ricardo Ibanco Cañete, Emma Lara Navarro,

Antonio Javier Lara Vives, Sara Lora Toledo, Juan Antonio Macià Agulló, Beatriz Maciá Ruiz, José Miguel Molina Jordá,

Beatriz Morcillo de Miguel, Rosario Torregrosa Martínez

Students of Chemistry and Biology, Universitat d’Alacant, CAT

Introduction

We have designed an introductory course on experimental science consisting of seminars, demonstrations and open experiments. The course, entitled From the images and the sensations to the measurement, was included in the 1998 Summer school of the University of Alacant at the Palau Comtal de Cocentaina, under the general title ‘Communicating Science: the Images of Science’.  
The 40-hour course is based on a graphics calculator (TI), various sensors and a device (CBL) that collects experimental data automatically. The equipment is easy to handle and allows carrying out experiments, both in high schools and introductory university courses, in a rather different way as compared with traditional laboratory courses.
The course was run along five days, and was attended by 30 students, apart from two lecturers and twelve other students that served as assistants.

The experimental set-up

Three elements are needed: a graphics calculator, an interface and various probes.

The graphics calculator (TI, Texas Instrument) is programmable and allows the collection, storage and analysis of data. TI and PCs can be connected to exchange information and programs.

The interface Calculator-Based Laboratory-System (CBL) is a hand-held electronic device for the recollection of data. The data registered by the CBL is exported to the graphics calculator in order to be analysed.
 

The probes are connected to the CBL unit. Up to five probes can be connected at the same time. There are over 40 probes available in the market to measure various magnitudes (motion, temperature, light, sound, pH, force, CO2, conductivity, heart rates, magnetic fields, etc.).

Most activities with the CBL require the introduction of the packs of programs PHYSICS or CHEMBIO into the calculator, to design the automatic recollection and storage of data in the experiment.

Advantages of the CBL system

As compared to a computerised laboratory, the main advantages of the present set-up are:

a) its manageability (because of its reduced weight < 600 g, it can be used as a home-lab),
b) no prior knowledge of computers is needed,
c) the exchange of information between calculators is easy,
d) an LCD plus an overview projector allows a large group of students (e.g., the entire class) to follow the experiment, and
e) its reduced cost.


Furthermore, in common with a computerised laboratory, this set-up allows for:

a) more time to design the experiments and to analyse the data,
b) the repetition of the measurement is easy and fast,
c) the data collection rates can be programmed and,
d) files with tables of values and graphics are obtained.
           

This experimental set-up can be used in a lot of areas. The TI is a versatile tool in Maths and the TI and the CBL combined are powerful resources to perform experiments in Physics, Chemistry, Biology, Geology, etc., both in high schools and introductory university courses.

 

The course:
From the images and the sensations to the measurement
 

Objectives

Learn how to use the TI and a CBL with probes

- Analyse phenomena related to the different sciences
- Design and carry out experiments related with the phenomena studied
- Think about the contribution of the experiments in the process of learning

- Discuss the advantages and disadvantages of the equipment

Each work group, of 2-3 students had:
-
a graphics calculator and a CBL interface with three probes
- an assistant (students already familiarised with the equipment)

- a notebook (outlines of the experiments proposed and a summary of the seminars).

Experiments

A night experiment was designed to measure variations of meteorological magnitudes (temperature, relative humidity and atmospheric pressure).


Out-door activities: the pulley

Half way through the course an out-door activity was organised with the purpose of both breaking the routine and proving that the CBL is easily transported.
The assembly consisted of a pulley that hung in a diagonal of the courtyard of the Palace of Cocentaina.
With the appropriate equipment the students slipped down the pulley either making measurements or being the subject of measurements by other students. Velocities, acceleration, heart rates, breathing rates... were measured.
The reports elaborated were discussed in a workshop by the end of the week.
The course had a strong practical component which was unfolded during the sessions, starting from the first day, but mostly during the last couple of days when the students, divided into small work-groups, and helped by an assistant, carried out experiments chosen from a multidisciplinary menu.  

Seminars

Although the course was mainly practical, it included some seminars, distributed conveniently, with the intention of introducing the students to new subjects, or generating discussions around the theme of the course. Some of the seminars given were:


- The measure of everything (Basic principles of experimentation and the models in science).     
- Instrumental analysis: transducers, sensors, and probes.
-
From images to sensations (The bad image in/of physics).
- From the sensations to the measurement (Weights and measures).     
- History of the measurement.
    
- Physical principles of some sensors.
    
- Calibration of sensors.

- Programming the TI —what it means.
-
Resources in the Web.  

Conclusions

40 hours are enough to introduce the package although it would, probably, be better to do it in 10 sessions spaced out in time rather than having them all concentrated in one week.
In spite of very different backgrounds of the students (concerning subject matter of studies or academic level), 6 hours are enough to learn the basic notions of the graphics calculator, that allow to run the programs and process the information.
The familiarisation with the use of the CBL and the different probes is gradual but fast.
The distribution of students in small groups monitored by assistants was decisive in achieving the goals of the course.