Caterpillars start as small wiggly creatures, go into a chrysalis, and then emerge as beautiful butterflies. But what happens in the chrysalis? Here is an experiment from the Otago Museum that illustrates this amazing science.

What you need
- a plate or a tray
- playdough
- vinegar
- baking soda
- eye dropper or syringe
EXTRAS: food colouring, paper or pipe cleaners and googly eyes
Instructions
- First, make your caterpillar like the picture above with circles for the body and a bigger circle for the head. You can add pipe cleaners and googly eyes to the head to make it look like a real caterpillar, or you can make them from paper, like us!
- Push your thumb into each playdough circle to form an indent.
- Fill each thumb indent with baking soda, and some food colouring if you would like to.
- Take the eyedropper and add drops of vinegar to the baking soda and watch what happens!
The vinegar and baking soda fizz and make the playdough turn into a slimy goo. That is what happens in the chrysalis – the caterpillar turns entirely into liquid and then reforms as a butterfly. It is amazing!
Right now, you will be able to see butterflies, and maybe the beautiful monarchs, floating around the skies. If you want to visit butterflies all year round, you can come to Otago Museum. We have the biggest science centre in New Zealand, and inside there is a Tropical Forest with hundreds of live rainforest butterflies. Come visit us!