Chemistry with LEGO® Bricks. An Innovative Method for Teaching Chemistry

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Science teaching in middle school is often not very effective. On the one hand, students have not yet developed the necessary ability to abstract in order to study infinitely large elements such as astronomical concepts or infinitely small ones such as atoms; on the other hand, schools do not have sufficiently equipped laboratories in order to safely carry out experiments in chemistry and physics. In the Comprehensive School of Siziano, where I teach, I have introduced an original and innovative methodology for the study of chemistry.

This teaching method originated from direct experience with the students and was developed in an attempt to meet their real needs in dealing with a subject that is often difficult for them.

While Bohr’s atomic model may be simple enough to have a concrete and logical idea of the structure of an atom, it is still complicated to visually understand how these atoms combine to form molecules.

The molecular models with balls are not suitable for this age group, the real need is to have structures that can be manipulated to get combinations that follow the laws of chemistry exactly.

In my classes, I often referred to LEGO® bricks and asked my students to imagine connecting atoms based on their shared electrons.

So we really used LEGO® bricks, I assembled a series of small kits with bricks of different shapes and colours to have a real and concrete experience, giving the kids the opportunity to “touch” the rules they had studied and thus create a virtual chemical laboratory.

 

Chemical rules

To properly use this experimental method, you must first deal with the chemical concepts in the traditional way.

First, students need to understand what a chemical phenomenon is and how it differs from a physical one; they need to know how to interpret the world around us as made up of elements that, when combined, form it.

 

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Bohr’s atomic model with orbitals is very important because it allows students to graphically represent all the main atoms in their notebooks. To facilitate these concepts, students should be shown Mendeleev’s periodic table, which represents all the chemical elements according to their number of protons and, therefore, their number of electrons, which are distributed around the nucleus and occupy energy levels, also called orbitals. It is then explained how the electrons are responsible for the formation of bonds according to the tendency of the atoms to reach the completion of the orbitals. The first orbital can contain up to two electrons, the second and third up to eight.

Of course, we are talking about a simplification of chemical concepts suitable for children in the first cycle of education. The numerical knowledge, where it is enough to know how to count up to 8 to understand chemistry, makes it very easy and very satisfying for the pupils, but we have to explain to them that in fact the orbitals are not as simple as they are proposed, that the behaviour of the atoms is not always the same in every situation, and that they will continue to study these issues more precisely. But since the most abundant elements in the biosphere are mainly four: hydrogen (H), oxygen (O), carbon (C) and nitrogen (N), knowing their basic behaviour is already a sufficient level of knowledge to get a general idea of the reality around us.

Of these main atoms (the first lines of the Periodic Table of the Elements) we can understand their valence, that is the number of electrons that are shared when they form a chemical bond, by simply observing their disposition in the Table. The eight main columns represent the electrons in the most external energy level. If an atom wants to have a complete level it will try to bind to other atoms which will receive or give electrons to achieve the so-called stability.

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The compounds take on specific names depending on the type of atom:

Metals (elements on the left of the table) form an oxide when they bind to oxygen.
Non-metals (on the right of the table) form the anhydrides.
The hydroxides are basic ternary compounds formed by a metal and as many hydroxide groups (OH monovalent) as the valence of a particular metal.
Acids can be either binary or ternary. The former are made up of hydrogen and a non-metal, while the latter are made up of hydrogen, a non-metal and oxygen.
Salts are formed by the combination of an acid and a base.

 

Use in the classroom

In order to use this method, the periodic table must be modified by creating an “extended” table. The chemical symbols have been supplemented by the representation of the elements with only their valences. For example, hydrogen (valence 1) is represented by a yellow brick with only one stud; magnesium (valence 2) by a black brick with 2 studs; carbon (valence 4) by a blue brick with 4 studs; oxygen (valence 6) by a red brick with 6 studs; and so on.

The most important piece for making combinations is a base plate with 8 studs. It is the base on which the molecules can be built.

With the table at hand, the students know how to build chemical molecules that are stable, because the model itself leads them to see if the procedure has been followed correctly, giving them immediate feedback on their work.

 

Results

After the first impact, when they thought it was a simple game, the students understood the complexity of the subject, but also the logic and simplicity that comes from modelling in this way.

They learnt how to make oxides and anhydrides, how to combine them with water molecules to make acids and bases, how to combine them again to make salts and to recreate water molecules. In short, it is a great job where sometimes the solutions come from the discussion with the teacher and the classmates, creating opportunities to stimulate the so-called soft skills that will be fundamental in their future.

 

 

 

About the author

Riccardo Bonomi, middle school teacher of Mathematics and Sciences and Scientix Ambassador, has always been engaged in the development of innovative teaching methods. He presented this teaching method of chemistry at the ‘Città della Scienza’ in Naples (Italy), at the festival ‘Science on Stage’ in Debrecen (Hungary), at the ‘Science Festival’ of Genoa (Italy) and at various international conferences. In 2022, he won the Italian Teacher Award.

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