Dr João Pedro Malhado and Dr Giuseppe Mallia
Teaching Assistants: Gabriel Duffett; Sophie Giraudon; Luke P. Siani; Emma Straker
The Global Summer School 2026 was a 4-day outreach event hosted at Imperial College at the beginning of July 2026, where circa 60 pre-university students from both home and overseas engaged in a series of chemistry related activities ranging from synthetic or analytical laboratory experiments to a computational chemistry activity. The morning of Day 4 of the summer school was devoted to an introduction to computational modelling taking place in one of the computer rooms of the department.
Computational chemistry is rarely included in outreach activities, since it is considered an advanced topic and therefore inaccessible to beginners. Based on our experience teaching computational chemistry from year 1 to year 3 of the undergraduate curriculum, we wanted to challenge this stereotype, and this is a case study discussing this experience.
While chemistry knowledge is based upon experimental evidence, and this is well illustrated in lab-based outreach activities, the interpretation of these experiments relies on abstract concepts and these minute invisible entities that are molecules. Discussions about molecules and their structural properties are part of chemistry teaching from its inception and are familiar to students at the pre-university level. Computational modelling including graphical interfaces for molecular structure representation is a powerful vehicle to interact with the “molecular world” and render this invisible and therefore abstract reality more accessible.
Another goal of this activity was to present a more diverse image of chemistry and of chemists. Chemistry is not only done in a laboratory by people wearing a lab coat all day long, and many chemists now rely on the computer and computer simulations for their research.
We used the software Avogadro in the activity, not only because of its versatility and ease of use, but also because it is free and opensource software, available for different operating systems and that participants will be able to install in their own computers and continue exploring in their own time.
In the computer room, each student had access to their own computer. Firstly, the general working of Avogadro was presented: how to create a molecular model, how to measure bond distances and bond angles, and how to determine and optimise the molecular energy. The remainder of the activity was broken down into sections, each proposing a challenge or a problem to students, that would then try to address it using Avogadro and with the help of demonstrators (a group of friendly recent graduates). After each section the main outcomes were summarised and discussed, before moving on to the subsequent task.
Section 1 consisted of modelling a range of simple molecules (H2Be, H2O, NH3, CH4) and describing their structure by determining the bond angles. The geometry of these molecules should not be completely alien to students, and here they should have the opportunity to inspect their shape in detail and also be reminded of the relationship between molecular geometry and energy.
Section 2 explores and contrasts the structures of benzene and cyclohexane. On paper both structures are represented as hexagons, are they both hexagons? Students are encouraged to explore the bond angles and explore different conformations for cyclohexane.
In section 3 students were challenged to draw different isomers with the chemical formula C3H6O2 and compare the energy of their own molecule with that of colleagues sitting around them. Any idea why the energy may be different?
Section 4 explores the enantiomers of limonene. Enantiomers is a topic that most students would not be familiar with. The two enantiomers are formed of the same atoms with the same bonds between them and they have the same energy. Are they the same? Why do they smell differently?
Section 5 introduces an “exotic” molecule which is dear to the department: ferrocene, which earned the Nobel prize to Geoffrey Wilkinson while at Imperial College. How many bonds is Fe forming? This example also serves to illustrate the limitations of the methodology and the knowledge involved in choosing it, as the energy of this molecule cannot be described by the simple interatomic potentials accessible via Avogadro.
Section 6 consisted of an introduction to crystal structures and the ideas of periodicity, the crystallographic cell, and building blocks. Cubic structures (simple, face-centred, and body-centred) were built using Avogadro, and the cell parameters and Cartesian atomic positions were inputted. The fractional coordinates with respect to the lattice vectors were introduced.
The session ended with a student feedback survey.
The introductory workshop was well received and was rated 4.11/5 on average by the students (46 responses). The computational chemistry session was considered interesting with an average rating of 3.76/5. The teaching materials were rated 4.17/5 overall.
Overall, the students seemed to have fun and enjoyed the learning activity. They appreciated that there was a gradual increase in difficulty, which was easy to follow.