Potatoes to plastic: turning potato starch into plastic

This is the second in a series of three posts about CIEC's latest free resource: Potatoes to plastic.

In the previous post I described how potato starch could be easily extracted from potato peel using simple equipment that is readily available in the primary classroom.  Here I will explain how the extracted starch can be used to make bio plastic in a few straightforward steps.  As this quote from a year 5 teacher shows, this activity is not only very engaging, but makes relevant links to the topic of Materials in the English and Northern Irish primary curricula, Earth's Materials in the Scottish curriculum and Myself and non-living things in the Welsh curriculum.

"They have absolutely loved this learning. Thank you for the opportunity to engage Year 5 in such an exciting and relevant project, which has reinforced their previous scientific learning of properties of materials (and has done so in a real-life context they will not forget!) as well as their scientific thinking. This project has led to many wonderful opportunities for cross-curricular links to reading, writing and maths too".

The procedure is even better if you are able to borrow a magnetic hotplate from a local secondary school or University, as can be seen in this demonstration.  However, even without access to this piece of scientific equipment the activity can still be carried out in a saucepan on a cooker hob.

To turn it into plastic, the potato starch need to be mixed with a small quantity of water, glycerin and white vinegar before it is heated.   The mixture is then spread out on a petri dish or saucer and left to harden.  After two or three days these simple ingredients will have set into bio-plastic.  The properties will vary depending upon the exact ratio of the ingredients and how thickly it was spread while drying.  The resource gives guidance as to how children could then investigate the properties of the finished plastic as they explore how it could be used in place of plastics derived from petrochemicals.

Children are invariably delighted with the finished bio-plastic

Experienced teachers will know that even the most engaging activity needs to be planned carefully if the potential learning is to take place. Consequently, the resource gives additional  guidance  including vocabulary prompt cards which support children to use the correct terminology as they describe what has happened.  This also supports them to link the experience to past science learning.

Children using the list of vocabulary to support them to talk about the activity in a more scientific way.

In the final post in this series I will explain how this resource can be used in English lessons and to develop children's understanding of how science is working to find solutions to other environmental problems.  

Full instructions including health and safety advice can be found in the free resource available from our website.

This post was written by Jane Winter who is one of our advisory teachers who works in Lincolnshire and Yorkshire.