How to Make a Molecular Model

During this exercise we are going to use readily available materials – that we can all find around the house or buy easily at the supermarket – to make a molecular model of a fragrance molecule.

The Propyl Ethanoate Molecule

We would like you to have a go at making propyl ethanoate (CH₃CO₂CH₂CH₂CH₃), and we want you to be as creative as you can with the materials you use! But remember that we still want to be able to see a true representation of the molecule (i.e. for it to have the correct 3D shape with bond angles that look reasonably accurate).

The following ingredients will be required:

• Sweets, Play-Doh balls or other round objects to be used as atoms, in three different colours (ideally red, white and black)
• Cocktail sticks, straws, pipe-cleaners etc. (something to be used as bonds).

Ensure that you read through all of the instructions before beginning the experiment to ensure that you understand exactly what will happen at each step.

Making Your Molecular Model

Step one: pick your fragrance molecule

We have made an attempt at recreating the ester we would like you to make (propyl ethanoate) – the skeletal structure is shown below.

Step two: pick your materials

For our molecules we have chosen to use red gummy sweets for oxygen, black gummy sweets for carbon, white mini marshmallow faces for hydrogen and cocktail sticks for the bonds. But this is where you get to be really creative!

You could use fruit, marzipan, Play-Doh… anything that you have around the house that could work as atoms and molecules – we’ll leave that side of things up to you.

Step three: have a go

Here’s a picture of our gummy sweet creation!

It can be quite hard to get models to stand upright, but the main thing is that you can use your model to help you visualise fragrance molecules in 3D. To aid stability, some of the single bonds in our gummy sweet creation needed two cocktail sticks positioned adjacent to one another – for the double bond, the cocktail sticks are well separated with an obvious gap between them.

When you are done we would love to see your creative masterpieces! Why not upload a picture of your model to our our open Padlet (we have included some examples from previous courses to help inspire you) or use the Twitter or Instagram #FLchemistry, to reveal how you got on.

If you need any guidance on using the Padlet, then further information is available – we would very much like for everyone to feel part of the learning community, so look forward to seeing your contributions.

Don’t Eat the Molecular Model!

For your safety it is advised not to eat any part of the molecular model you have made at any stage of the experiment (unhygienic handling of foods may result in contamination). Dispose of the samples into a general waste bin. Take appropriate precautions when using cocktail sticks – or other sharp objects – to ensure you do not injure yourself.

Why not give it a go?