Making STEM Christmas Cards with Letterbox Lab

Want your kids to have festive fun combined with awesome science activities? Make STEM Christmas Cards with Letterbox Lab!

Letterbox Lab creates monthly science kits for children (click here to see) and they’ve put that combination learning and fun into a set of scientific Christmas cards. 

A few weeks ago we were given a sneak preview of their STEM Into Christmas cards, which are on Kickstarter right now. We’ve now been lucky enough to have been sent the actual card kits to try out. 

There are four designs, each with a different scientific theme. Each card comes with full instructions plus all the bits and pieces you need to make it.

Letterbox Lab Christmas Cards

Rainbow Christmas

This design uses diffraction grating to create a rainbow Christmas gift. If you don’t know what that is, you’re in for a treat.

This is what happens when you hold it up to the light. Rainbows!

A rainbow present is created using this little piece of plastic. This card is mainly assembly; the learning part of it is the effect it creates.

Letterbox Lab Christmas Cards

See? This is what the recipient sees when they open up the little present and look through it at a light. You can also see different effects and patterns depending on what kind of light source you look at.

Merry and Bright

Letterbox Lab Christmas Cards

This is another one that is simple to put together but looks lovely. A sheet of sticky photochromatic paper is included, and your child cuts out whatever shapes they like. There are templates included, or you can go freestyle.

Letterbox Lab Christmas Cards

The shapes will change colour when exposed to sunlight, showing the decorations. 

Much to our annoyance, it was pouring with rain when we were making this card, so the shapes were not very visible. But when the sun shines it’s amazing seeing the colour change!

Save Santa

Letterbox Lab Christmas Cards

This card uses hydraulics. It also requires a fair amount of precision to create the mechanism, involving filling syringes and a tube with water, and connecting them up.

Letterbox Lab Christmas Cards

Then you assemble the card itself.

Letterbox Lab Christmas Cards

Santa pops out of the chimney! This is a terrific one to play with.

Don’t Have a Blue Christmas

Letterbox Lab Christmas Cards

This was the most involving of all the cards, and also the messiest! The science part was exploring chemistry with acids and alkalies.

It involved soaking blotting paper with cabbage juice (really) for Santa’s cold blue cheeks.

Letterbox Lab Christmas Cards

Then experimenting with acid (cream of tartar) and alkali (bicarb) to see how the colour changed.

Letterbox Lab Christmas Cards

Can you remember your school science lessons? Which one turned the paper pink?

Now, technically you send the card with the blue cheeks, and put instructions in the card for the recipient to make the colour change themselves. But Little C was very keen to do the complete colour change, so in the interests of science we used lemon juice to complete the experiment.

The best thing about this card was that the fun didn’t stop there. There was plenty of blotting paper and cabbage juice to continue playing, and that was exactly what Little C did!

Letterbox Lab Christmas Cards

I had more cream of tartar and bicarb in the cupboard, and she spent absolutely ages adding one then the other, changing the colours, mixing them all all. The colours were beautiful, and this was incredibly engaging. It was also satisfyingly messy!


This is terrific set of experiments. There’s plenty to learn and do, and I love the idea of combining science with Christmas cards!

Making these cards would be the perfect November activity. Friends and family would be very impressed to receive them.

They would also be wonderful to give to other children, as they all offer something special to the recipient as well as to the maker.

Learning through play is an essential part of childhood, and Letterbox Lab always gets the balance between the two just right. Children are encouraged to be curious and creative, and open their eyes a little bit more to the wonders of science.


Huge thanks to Letterbox Lab, have a Merry STEM Christmas!

You can buy these card kits over on Kickstarter right now. 


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Combine science fun with Christmas with these fantastic STEM Christmas cards from Letterbox Lab

Letterbox Lab is the kids’ science kit reinvented to be more fun, more colourful, more convenient and more educational. A series of 12 innovative science kits delivered to your home that build upon each other as you make your way through the series.

This is a science kit that arrives through your letterbox containing everything your child needs to start playing with science. But it’s much more than that. It’s the beginning of an adventure that will take your child over the rainbow, across space and into the inner workings of the natural world.