Experiences

Web chemistry

Chiara Cheti

Italy

Vocational School

Chemistry

Teaching in class, Laboratory, Online Learning

Direct

Web Chemistry is an experimental path with the aim of encouraging the students towards the study of the Chemistry. In fact, this subject is considered obscure and far from real life.
During so many years of teaching, I have encountered only few students dealing with chemical issues with logical reasoning.
In order to overcome this problem I looked for didactic methods not starting from the teaching of the invisible atoms and molecules, but from mixtures and solutions analyzing materials of ordinary usage.
The following step was the separation of the mixtures in order to identify the constituent elements and then the methods to calculate the ratio between solute and solvent within the solutions.
Only at the end we came to the pure substance, the atoms, the molecules and the mole.
In the framework of this initiative we undertook many activities: one of these concerns the discovery of the factors influencing the speed of chemical reactions.
The experience is based on the fact that the temperature, the physical state of reagents, the concentration of reagents and the excitement can accelerate the reactions. For this purpose we broke up cupric sulfate crystals and inserted the matters into two different water containers: into one the broken up salt and into the other the intact crystals salt. The reaction is more quickly into the container with the broken salt.
Second experience: the diluted hydrochloric acid melts the shells (full of calcium carbonate). Increasing the concentration of acid the melting of the shell is more quickly.
Third experience: 2 containers filled with water and NaCl; we shake only one of them. Shaking, the salt melts more quickly.
Fourth experience: 2 beakers filled with 10g of potassium dichromate in 100ml of water; we warm up only one of the beakers. The melting process is quicker for the warmed up beaker.
The whole work course is carried out along the entire scholar year whether through experiments or through the construction of thematic map with the usage of whiteboards.
The material produced has been uploaded on the school website interactive shared section.
In the framework of this initiative it is has been also realized a didactic game “The Chemical Domino” to help students in memorizing the name of unions of elements.
The reached results to date are encouraging.