Molecular magnetic building kit

Thanks to its modular nature, this kit is suitable as a didactic tool both for the last two years of primary schools, where chemistry is taught, and above all for secondary schools, where the chemistry is part of their curriculum, such as gymnasiums, industrial schools and vocational schools with compulsory chemistry lessons. However, this tool can also be used in some universities and in extracurricular education, e.g. in science clubs.

Due to the required precision and a certain manual dexterity during assembly, the actual printing and post-production adjustments are suitable to be carried out with older students of secondary schools, or with a pre-selected group of students in the second grade of elementary school who have already demonstrated their skills. In any case, due to the use of acetone or superglue, the work should always take place under the supervision of the teacher.

A moderately advanced student can successfully complete the task independently. In the case of the teacher's assistance, however, its implementation is possible even for beginners with only basic knowledge. During their work, students will be working with already prepared, semi-finished models exported from the Fusion 360 program. For successful implementation, students should be able to handle the preparation of a print file and printing on a 3D printer. When assembling, students must be able to remove the supports using pliers or tweezers and to glue accurately and cleanly using acetone and/or superglue. In order to assemble correctly, they should also understand the principle of how magnets work and be able to estimate the course of magnetic field lines for different directions of magnetization. Assembling the model is moderately challenging for good eyesight and fine motor skills and may therefore be too challenging for physically or sensorially handicapped pupils.

Thanks to the commonly used stick models, students in chemistry classes try to imagine molecules as connected isolated spheres. During the production of a molecular model, they learn the basic properties of organic molecules, such as the effect of an atom of an element and its hybridization on the volume in space, its binding capacity, and above all the lengths, angles of the bonds and their free or limited rotatability around the axis and steric complexity. Thanks to the possible comparison with more common stick models, they will also understand the difference between reality and a model, when the model is always able to convey only some properties of reality.

For the construction of the model, magnetic connection is chosen, which prevents the most common mechanical damage to the models by breaking their joints, and at the same time models the functional properties of real chemical bonds, such as limited rotation or a decrease in the acting force with increasing distance between atoms.

The actual result of the students' work is a kit of molecular models that can be used in the teaching of organic chemistry. Both during the actual interpretation of a new substance, and during practice, or when visualizing organic reactions during laboratory exercises.

Hardware, software, tools, materials:

• PLA filaments in various colors. Recommended colors of the atoms: carbon/benzene –

black, hydrogen – white, oxygen – red, nitrogen – blue, sulfur – yellow, halogen – green 

• Acetone (industrial) (5 ml) + brush or a cotton swab for application
• Superglue (liquid)
• Tweezers or combination pliers with narrow jaws to remove supports
• A small hammer or tool with a wooden handle to correct the alignment of the magnets
• Neodymium magnets:
  • Disc magnet Ø 5 mm, height 5 mm, neodymium, - nickel-plated surface

https://www.unimagnet.cz/kt-05-05- n_z320/?&utm_source=notification&utm_medium=email&utm_campaign=ord er_create

• Disc magnet Ø 5 mm, height 5 mm, neodymium - PTFE surface (optional)

https://www.unimagnet.cz/kt-05-05- t_z387/?&utm_source=notification&utm_medium=email&utm_campaign=orde r_create

• Bar magnet Ø 4 mm, height 10 mm, neodymium DIAMETRALLY MAGNETIZED! https://www.unimagnet.cz/t-04-10-dn-diametral_z759/?&utm_source=notification&utm_medium=email&utm_campai gn=order_create

Time estimation for model preparation:

• Introduction of the model and pre-print preparation of selected components of the kit – 30 minutes

Time estimation for printing individual parts:

• Model of carbon atom (sp3, sp2, sp1), oxygen atom (single bond, double bond) and nitrogen atom: 2 hours 10 min with LH 0,20 mm and 15 % infill, resp 2 hours, 50 min pro LH 0,15 mm a 15 % infill
• Hydrogen atom model (1 hemisphere with supports): 30 minutes with LH 0,15 mm and 15 % infill. (Lower resolution is not recommended.)
• Sulphur atom model: hours 30 min with LH 0,20 mm a 15 % infill, resp 4 hours 30 min with LH 0,15 mm and 15 % infill
• Halogen atom model: 3 hours with LH 0,20 mm and 15 % infill, resp 5 hours 20 min with LH 0,15 mm and 15 % infill
• Benzene molecule model (with supports): 11 hours with LH 0,20 mm a 15 % infill, resp 14 hours with LH 0,15 mm and 15 % infill

• Removing of the supports:
  • (hydrogen atom and benzene molecule) – 5 minutes

• Placing the magnet according to the correct polarization and attaching it
  • Approx. 2-3 minutes for each magnet.

• Placing and uniting the model hemispheres
  • 3 minutes preparation, 2 minutes for each atom

Estimated total print time for the components of the acetone (C3H6O) molecule model: 11 hours 40 minutes + 120 minutes for prepress and printing.

• (2x carbon sp3, 1x carbon sp2, 1x oxygen double bond, 6x hydrogen)

Estimated total print time for the components of the styrene molecule model (C8H8):

• 19 hours 20 minutes
• + 120 minutes for prepress and print adjusting.
• (1x benzene, 2x carbon sp2, 8x hydrogen)

See attached file Molecular_magnetic_building_kit_Guide.pdf