Pet molecule

In the grade 11 curriculum the students study the 3D structure of molecules. We use molecular model kits to show the students all of the VSEPR formations in 3D. In the 1960s there was a Pet Rock marketed that involved a decorated box, a rock and an instruction booklet with information about your Pet Rock inside. Many of us were gullible enough to pay money for it!

I got the idea many years ago to have the students construct a marketable Pet Molecule in a box much like the rock. It really caught on, the kids love it and many pet molecules later it is still one of the highlight projects in my grade 11 course. I make every attempt to build the arts into my science courses.

Students who are good at creative writing or construction really get into this activity.

boxes and a molecule -- the boxes are all decorated with molecules - also a little booklet so it looks like a "pet rock" box except it is for molecules


To construct a decorative box, with disassembled molecule and information booklet inside ready for sale at your local science “pet” store with information to construct your very own pet!


  • Polystyrene spheres of various sizes depending on the number and different atoms in the molecule
  • Toothpicks, pipe cleaners, etc., for the bonds. Must be rigid.
  • Construction materials for the box — wood, plexiglass,
  • Bristol board, cardboard, glue, decorations, bar code, plastics, etc.
  • Tempera paint or acrylic for polystyrene spheres


  1.  The box is a 10 cm cube made of rigid material, constructed for marketing — molecule’s name, company and bar code on the outside. The box must contain everything and be able to open and close for reusability.
  2. The atoms (polystyrene spheres) are selected so that they fit into the box, are colour coded as the teacher prescribes and have bond placement positions marked on each sphere for easy construction. The bonds are marked with the proper scale bond lengths in appropriate units so that the depth they are pushed into the spheres is visibly marked.
  3. Included in the box is a card that has the names of the project people as labelled manufacturers.
  4. The instruction booklet that fits into the box should include:
    • personal information about your pet – family tree, species photos, habitat, etc.
    • training, care, food, exercise, games, songs, TV, clothes associated with your pet 
    • where this particular breed is found in the world other breeds available health info including physical and chemical properties
    • 3D coloured picture of your pe
    • stepwise instructions on how to construct your pet with diagram
    • the friendship and protection your pet provides you
    • birth certificate

Some suggested molecules are:


An assessment rubric can be set up to evaluate this assignment. The Pet Molecule assignment is great for display both in the box and constructed. The project is given to you in its marketable format, not put together. You won’t believe what the students will come up with. Every box holds a surprise. boxes and a molecule -- the boxes are all decorated with molecules - also a little booklet so it looks like a "pet rock" box except it is for molecules