Sustainable Stories: Which Plastic?

This blog post is brought to you by Jane Winter, one of our advisory teachers who works in Lincolnshire and Yorkshire.

Although the materials for this investigation are free and readily available, they can be a little tricky to source.  However, it is well worth taking the trouble to do this as, once you have, everything else is very straightforward.  When I have done this activity I have found that there is a real buzz in the classroom.  Moreover, you could easily provide enough equipment for a whole classroom full of socially distanced youngsters to do the activity at the same time.

The tricky bit

You will need samples of some different types of plastic. 

Sample 1: The thin clear plastic that often comes around packs of Christmas cards and in some other packaging
 Sample 2: Foam plastic (expanded polystyrene, PS) used as for takeway foods such as burgers and chips

Sample 3: Polystyrene, as used for the lids of takeaway coffee cups. The name of this plastic surprises the children, as ‘expanded’ polystyrene is commonly referred to as polystyrene, but for scientists, there are two types, and this one is un-expanded!

Sample 4: The plastic used for milk bottles (polythene, HDPE)

Each child will need a strip of each plastic cut to approximately 8 x 1 cm.  They will also need a bowl, jug or tub of water large enough to put their hand into and some table salt.

Top Tip 

This is one activity that you really must try out for yourself before letting your class lose with it.  Manufacturers sometimes change the formulation of their plastics and so they don’t always behave as you expect them to!

The fun bit

Children test each sample to see if it floats in water or in salt solution (brine) and how it reacts to being folded.  The results of their tests will let them identify what each sample of plastic is made of.  For example, PVC and polystyrene will both sink in plain water; but if salt is added the polystyrene will begin to float.

This is an important thing to be able to do as different plastics are recycled in different ways so we need to be able to identify them.  At this stage I have found that providing children with a simple table helps them to organise their data as they carry out the tests.  

Full instructions, including safety notes, for how to do the activity are provided in this free to download resource.

This activity builds on the work that children have done on materials in KS1. It helps them to develop their skills of working scientifically by sorting in a more sophisticated way.  There is a simple sorting key on activity sheet 5 of the resource which will support children develop their understanding of how keys work, as they use it to classify their plastic samples.

As children start to think about the reasons that we might need to be able to classify materials more precisely they can begin to consider why and how this science might be used in industry.  A class discussion will help them to understand that being able to use post-consumer waste makes processes more economically viable as well as more environmentally friendly.  These sorts of links help to raise children’s science capital as they see how the science that they do in school has real life applications and is relevant to their lives both now and in the future.

To coincide with InternationalWomen in Engineering day we have published a new IndusTRY AT HOME activity for you share with families.  Why don’t you put a link on your school website?

For a broader set of activities linked to this topic, please go to http://www.ciec.org.uk/resources/plastics-playtime.html which expands the topic to look at the heat insulation and shock absorption properties of plastics – and children design and test packaging to protect parcels of fragile crisps, which they post back to themselves in school – the ultimate test of their designs!

Medicine from microbes: Investigating mould

This month’s somewhat mouldy offering is written by Clare Docking who is one of our advisory teachers in the East of England.

Children always love the yuck factor and growing mould is no exception!  I have found that they are fascinated to watch how mould changes over time and keen to record what happens when given the opportunity to deliberately do something that we usually tell them to avoid.

In the news

I had been looking forward to highlighting that 2020 was Florence Nightingale’s 200^th birthday when doing this activity in school this year.  However, the pandemic put an end to me doing any work with children for the time being.  However, this is a great opportunity for you, if you are currently working in school, to involve children in an exciting science activity while making relevant cross-curricular links with history and English.  It also ties in well to the current situation as children will have been hearing a lot about microbes lately. This is also a chance to reinforce messages about hand washing as this gives children direct evidence of some of the microbes in our environment.  Furthermore, you can use this activity to allay children’s anxieties by encouraging discussion about science helping us to overcome many health issues over time (such as the discovery of antibiotics for example).  Let children know that scientists around the world are collaborating to find a vaccine and treatment for Covid-19.

The information here is for teachers working with children in the classroom.  There is also support for families trying the activity out at home in our free to download IndusTRY ATHOME activity sheet. We think the activity lends itself to being done at home or in a socially distanced classroom, as the resources needed are cheap and readily available so each child could have their own.

Let’s investigate!

Children love a challenge so start the investigation by reading the news report from a fictional bio-tech company (provided in the resource), and tell the children their help is needed to find out which conditions are the best for growing mould. Encourage them to draw on their own experiences when thinking about different conditions – why do they think food left in a cupboard or lunchbox for too long goes mouldy?  Where do we usually store food and why do they think this is? Is food kept warm or cold to preserve it? At this point listen to the children’s ideas and see if they suggest that moisture, temperature and light make a difference to growth. This is a good opportunity to bring in previous learning about growth of other living organisms such as plants which may prompt ideas. 

Did you know?

A microbe is any living thing too small to be seen with the naked eye.  This includes some fungi (which include the ones which cause mould), bacteria (some of which cause diseases) and viruses such as the one that causes covid-19.  However, not all microbes are harmful and many, such as the ones that live in our gut, are essential for our health.

I have not used this activity with younger children but Jane Winter, in the CIEC team, asked Kathryn Horan (@SciKathryn) about her experience of doing a similar activity with her EYFS class.  Apparently they were fascinated when they compared bread that they had touched without washing their hands and a fresh piece of bread.  They were able to make sensible predictions based upon their experience, saying such things as ‘I think that the dirty one will go black’.  We agreed that this would be an activity that would lend itself to being used with a mixed age group in the current situation.  

Kathryn Horan's (@SciKathryn) class were fascinated to watch what happened to a slice of bread that they touched without washing their hands first!

One of the things I particularly like about using our resource is that children are motivated to record their findings knowing that it is going to be used by a real bio tech company. A mixed age group could work together to produce different elements of a report which could include videos, letters, captioned photographs and graphs.  If they send their report to CIEC@york.ac.uk they will be delighted to get a reply from the company!

Top Tips

Here are some tips to make your investigation a success:

•  Spraying the bread with water will ensure that the moisture is evenly spread before it is sealed in the bag. 
•  Make sure the bread doesn’t contain preservatives or it may take much longer to get results. 
• Very occasionally, the children find they don’t get the expected results from an investigation, especially if working with living things. Use this as a learning point to do further investigations and tell the children that scientists sometimes experience this as well, however, discoveries are often made from things not turning out as expected.   

IMPORTANT Don’t reopen the bag once the investigation has started. This is because potentially harmful spores from the mould could be released into the air.  Once the experiment is complete, enclose the sealed bag in another sealed bag before disposing of it.

Full details of this activity can be found in our free resource and includes teachers’ notes, children’s activity sheets and national curriculum links.