Teaching Resources

Jérôme KARIGER

PhET (Build a molecule)

This resource helps addressing the transition from the molecular model to symbolic writing and vice versa.
It also allows addressing the notion of valence of chemical elements and better understand the possible problems manipulating objects in the animation (for instance: a students has to create a C2H4 molecule and first bonds the 4 H to one C. He notices he cannot bond the last C. He realises that hydrogen with a valence of 1 can make only one bond and that carbon with a valence of 4 can only make four bonds). At another level, this animation can be used to address the geometry of molecules and their organisation in space.

With this animation, it is possible to meet the objectives of the curriculum “Molecular formula” and “Representing a molecule with a formula”.

The animation can be used online or downloaded. The benefit of downloading it is that it t can be used without an Internet connection, moreover, it can be put in several computers in network and students can use it without going through the Internet, which can take time and distract the students.
The website PhET contains many science animations. Main benefits of this website: animations in French, free of charge, freely downloadable and scientifically relevant.

The resource was used in a third year class, Socio Educative Transition with 12 students at Institut Sainte-Thérèse D’Avila in Chênée (Liège). The resource was used in a peculiar way. Indeed, it was saved on the school sever. In a cyberclass, the students accessed it on individual computers and could freely use it for around twenty minutes.

This animation was used to refreshed previously seen notions; it was used as an exercise.
It followed this approach:
- Modelling was addressed previously
- Theoretical notions such as molecular formula, valence,… had just been seen
- Consolidation phase, training exercises
- Animations on computers. One student per computer. Students go as far as they can within the time limit (around twenty minutes) at their own pace. They are allowed to ask questions to the teacher.

The information gathered in the questionnaire must be mitigated, for the questionnaire was completed too quickly at the end of the lesson (in a few minutes) and not all students could answer. Moreover, the conditions were not optimal to have the most honest and in-depth answers.
Regarding the questionnaire handed to the students, 4 students out of 9 thought the resource was motivating. All the comments on the activity are positive. Students are not particularly convinced that the resource will help them more. The resource brings two “manipulations”; one to build molecules, the other for 3D modelling (swinging images). One or the other was preferred, depending on the students. Students are little convinced that it helps them better understand reality. 7 out of 9 feel somehow at ease to explain the studied chemistry content.

This ICT resource was used in relation with physical models (that students could handle). I think combining the two approaches is interesting and strengthen students’ understanding. I did not have the chance to assess the studied notion during my internship. The real benefit of the sequence was that students had access to a computer and could manipulate the resource on an individual basis at their own pace. After 20 minutes, the quickest students had not run through the resource. While the students were working, I went to each of them to ask questions, see what they were doing,... This approach tends toward individualisation, another form of differentiation that we seek.