3. Week 03

Curriculum alignment. 3D printing.

The valence of atoms: connections with dovetails

This week I wanted to finish a project that I’ve had in mind for a long time. I wanted to make a model with which the students can learn and practise the valence of atoms. A short explanation:

The valence of an atom of a chemical element indicates how many atoms it can bind to itself in the case of a chemical bond, or how many single bonds it would have to form with other atoms in order to reach the octet state.

The idea is to print atoms of different elements as cubes and to be able to connect them with other atoms through chemical bonds. The elements have a certain number of notches that correspond to their valence. For better durability of the bonds, the connections should be designed as dovetails.

Cubes printed!

I decided to create the design in OnShape. This program is initially more complicated to use than tinkercad, for example, but in the end it’s worth it because the design is easier to reproduce and small adjustments are easier to make.

So I had to design the cubes first. To do this, I simply had to create a square surface and extrude it. The element symbol (water fabric) was sketched onto this square surface and then extruded. For the binding, a triangle was sketched on the upper edge and cut into the cube. For other elements, the design could simply be transferred, whereby the cut-outs for the bindings only had to be mirrored with a mirror axis diagonally through the cube. The bindings were constructed in such a way that they fitted into the triangular cut-outs of the cube at both ends. With 3D printing, it is necessary to insert an offset so that the parts can slide into each other. I therefore reduced the size of everything here by approx. 0.2 mm. But I still have some work to do. Cube!

Reflection

Are you planning to use the fabricated object in your classroom? If so, how?

Yes, as I explained above, it is a model for the valence of different atoms. Students can form different molecules and write down their molecular formula. In doing so, they understand valence as a topic more deeply and practice through hands-on activities, which causes deeper learning.

Think on a learning activity involving 3D printing. How could it be aligned with your curriculum / standard? What are the challenges?

As models play a major role in STE(A)M lessons, it is easy to integrate activities into the curriculum. Atomic models, valence models, molecules and so on can simply be designed in tinkercad, for example, and be printed out. The challenge with these activities is always that the curricula are very tight and these activities take time. However, they will make up an increasingly large part of my teaching. They are even easier to integrate into technology lessons, as the process of designing and 3D printing alone fits well into the curriculum. For example, you can 3D print cases and models (e.g. gears).

Have you started an educational portfolio? Why or why not? . In your opinoin which are the advantages of having these education portfolios? How do evaluate success a learning activity and how do you keep track of possible modification/improvements ideas?

I tried a few times. I do very occasionaly. But it is too time consuming and mostly I am glad when I get done with my work.