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