Studying thermal equilibrium with temperature sensors and a film canister Sarantos Oikonomidis Dimitrios Sotiropoulos George Kalkanis University of Athens Pedagogical Department Laboratory of Science Technology and Environment 13a Navarinou St. Athens GR

Quotation from a Greek tragic poet One must learn by doing the thing. For though you think you know it, you have no certainty until you try. Sophokles

Since 2004 all the students of Pedagogical Department (300 per year) perform hands- on experiments with the use of sensors. The experiment we present in this paper is characterized by the simplicity of the experimental procedure. The same experiment was performed by 80 pupils in the second year of high school, last year.

The aims The students distinguish the concepts temperature, heat and thermal energy. They familiarize with sensors use. They aware the advantages of Microcomputer Based Laboratory. (students only)

The experiment The students use two temperature sensors connected to a computer, a plastic cup with tap water (about 20 o C) and a film canister with hot water 80 o C.

The basic question Which will be the final temperature of the water in canister and the final temperature of the water in plastic cup after the thermal equilibrium? hot water 80 o C tap water ~20 o C m tap water >m hot water film canister filled with hot water 80 o C plastic cup with tap water ~20 o C (the canister cup must be out of the tap water)

Hypothesis – Predictions Many students reply that the temperature of the water in canister and the temperature of the water in plastic cup will be about 50 o C, after the thermal equilibrium.

Discussion – Conclusions After the thermal equilibrium, the temperature of the water in canister and the temperature of the water in plastic cup is ~35 o C. The results of the experiment make the students realize that what is transferring is not temperature. The discussion leads the students to distinguish the concept of heat, temperature and thermal energy.

The results that came up from this computer-based real-time experiment are very encouraging. We perceived a large improvement in post-lab work, using pre-labs prior to starting the experiment. The students lead to significantly improved learning and retention. After the lab the students express with the right way for the concepts: temperature, heat, and thermal energy.

The students are assessed with Report sheet of lab exercise. Observation sheet of team behavior. Self assessment form.