Every year chemists at schools and universities around the world take part in what has become a Christmas tradition to brighten up classrooms and labs: they create Christmas trees out of chemical apparatus, also known as chemistrees. We’ve picked five of our favourites from this year.

First up Emmanuelle Ruelle and her students in France have created a colourful rainbow chemistree and if you look closely the students have also decorated it with silver-mirrored test tubes.

2 Year 12 students at Cheam High School in the UK took inspiration from this year’s Nobel prize in chemistry to create their chemistree. Their coloured glass round-bottomed flasks represent the effect of particle size on colours observed in quantum dots. If you want to learn more about quantum dots we’ve got an explainer on the topic.

3 An eclectic chemistree from Chris Marsh at the University of Leicester features more silver-mirrored flasks and what appear to be impressive copper sulfate crystals.  

4 Jari Yli-Kauhaluoma at the University of Helsinki in Finland has created a sizeable (and bright) chemistree in his lab.

Our final chemistree was created by Andres Tretiakov, a science technician at St Paul’s School in the UK, who has done a clever bit of microwave chemistry to produce carbon nanodots. These carbon quantum dots glow under UV, something harnessed here to create an interesting display.

John O’Donoghue at Trinity College, Dublin has also been running his annual chemistree competition. Check out his top picks for more festive chemistry.

And finally…

Not a chemistree in the conventional sense but well worth an honourable mention. This team at Nanjing University in China created a system for 3D printing polylactic-co-glycolic acid microneedles that was then put to use creating a Christmas tree design. While the researchers’ 3D printing system can produce attractive designs, the reason they developed it was to produce cheap microneedle patches for drug delivery. The polymer the 3D printer deposits can be loaded with different drugs and vaccines and when a microneedle patch is applied to a person’s skin the needles deliver the drug painlessly.

Source: Y Li et al, ACS Nano, 2023, 17, 19925 (DOI: 10.1021/acsnano.3c04758)