Simulation of weather conditions essential along the salt production process: Solar radiation effect on the evaporation rate
Having as background the Aveiro saltpans and all the procedure for obtaining salt from them (evaporation of water), an experience was planned in order to study the effect of solar radiation on the evaporation rate. A saltpan was simulated in the lab, prepared in a dark room (without natural sunlight), and, with a floodlight, we simulated the sun. We varied the angle of incidence of the radiation in the saltpan and then we measured the temperature as well as the range of mass of the saltpan during a certain hiatus of incidence of the floodlight. In order to study the water evaporation rate with and without wind, a fan was used.
This activity intends to make the students understand the procedure for obtaining salt on Aveiro saltpans and in which way the weather conditions can restrain it. This activity involves the performing of experiences that concern some competences like: planning an experimental activity, identifying both the variants of study and control, making the correct register of measurements; interpreting the results. Experiment 1 Experimental Setup -Inclination: 90º (vertical) -Mass concentrarion: 25g/100 ml -Ambient temperature: 23,0 ºC -Floodlight power: P=500 W -Pan dimensions: 45,00cm x 28,00 cm Note: it was used an aluminium pan. The experience was made with no sunlight (at night). Only the floodlight was falling on the pan. Experiment 1 Experimental Setup - Inclination: 90º (vertical) - Mass concentrarion: 25g/100 ml - Ambient temperature: 23,0 ºC - Floodlight power: P=500 W - Pan dimensions: 45,00cm x 28,00 cm Note: it was used an aluminium pan. The experience was made with no sunlight (at night). Only the floodlight was falling on the pan. Experiment 2 -Mass concentration: 25g/100 ml -Ambient temperature: 16,3 ºC -Floodlight power: P=500 W -Pan dimensions: 45,00cm x 28,00 cm Note: it was used an aluminium pan. The experience was made with no sunlight (at night). Only the floodlight was falling on the pan. This and other experiences can be seen on www.sal.spq.pt