A Pinch of Salt

Today's post is brought to you by one of our advisory teachers, Jane Winter

The weather is getting colder, and our thoughts are turning to icy windscreens and slippery roads! As gritter lorries gear up for action, a useful way to link this seasonal change to the science curriculum is with CIEC’s A Pinch of Salt. This free resource provides a real life context in which children can apply learning objectives and practise vocabulary from the science curriculum. 

It's working! Watching the clear salt solution drip through the filter paper.

In one activity children are first invited to compare a sample of pure salt with some rock salt. They are asked to consider how they could extract salt that was pure enough to use on food from the rock salt that is used for gritting roads. The process starts by dissolving the rock salt sample in water before filtering it to remove all the undissolved solids. The water is then evaporated from the salt solution to leave behind salt. The evaporation can be sped up by leaving the solution on a radiator or by using a tealight. 

The resource contains all of the information that you need to carry out this easily resourced activity.

 If you would like to try this, or any other activity, from A Pinch of Salt you will find that it is fully supported with teachers' notes and activity sheets for children. There is also safety guidance including information about NOT actually using salt purified in this way on food and the safe use of tealights. We would love to hear about your experiences of using this, or any other CIEC resource, and will send a hard copy of our acclaimed 'Working Scientifically' to anyone who shares their experiences with us.

New sustainability science activities from CIEC

This blog post it brought to you by Jane Winter, one of CIEC's advisory teachers

CIEC has started the new academic year by adding some more activities to the existing sustainability resource.  Like most CIEC publications these engaging and easily resourced investigations link real life science solutions to environmental problems and the primary science curriculum. 

Sponsored by Innospec, a company that develops personal care products, the investigations support children to consider the environmental impact of products such as soap and shampoo.  In one activity children explore the efficacy of solid and liquid formulation of soap and research the different transport and packaging requirements of these everyday products.  In another they plan an investigation to assess the suitability of different packaging materials, including an innovative soap wrapping that Innospec scientists have developed which dissolves the first time that the soap is used, thus reducing waste.

Children are motivated to work on these challenges to find out how science can provide solutions to environmental problems

As well as linking to the materials strand of the KS2 curriculum the activities provide ample opportunities for working scientifically including observation over time, secondary research and planning a fair test.  There are also cross curricular links including producing written reports for the scientists at Innospec and creating tables and graphs to display measurements taken during the investigations.  

The PowerPoint, which is included in the resource, provides open ended starting points for classroom discussion, letters from the scientists at Innospec and a short video highlighting the long term environmental impact of single use plastics including packaging. 

The resource contains a short video which provides a context for the investigations

These activities, and many more, are free to download from the CIEC website.  If you use this resource in your classroom we would love to hear from you to hear how it went.  Get in touch (preferably with photographs) at CIEC@york.ac.uk and we will send you a hard copy of some of our resources to say thank you.

An Eggciting Easter Challenge

Today's blog post is brought to you by Mackayla Miller, one of our advisory teachers based in the North East.

Happy Easter folks! Here at CIEC, it’s no yolk that we’re egg-stremely eggs-cited about inspiring the next generation of scientists and engineers, but we’re also partial to a few terrible egg puns at this time of year.

Mackayla has been working with the year 6 children at Levendale Primary School to deliver our egg-cellent Children Challenging Industry (CCI) programme. The ‘Eggs-press Delivery Challenge’ was a tough challenge indeed, but this egg-ceptional group of pupils were willing to whisk it all and refused to be beaten. Working in teams with a budget to spend, the groups hatched their plans, packaged their eggs, shelled out for their materials, and are now eagerly awaiting the arrival of their packages in the post to see to see whose eggs survived the journey.

John Baker and Paul Bickley from Teeside plastics manufacturing company Alpek Polyester UK Ltd, joined the classroom sessions via Zoom to give the children an insight into their jobs and engage them in a remote site visit, including an exciting interactive bottle-drop investigation. But it’s not just the children who benefit from the Children Challenging Industry experience. Here’s what John Baker, HSEQ and Technology Director has to say about getting involved:

“I’ve been involved with CCI for nearly 10 years now and every session, whether face to face or more recently using video conference, is great. The engagement from the children in the classroom is fantastic, with them often asking challenging and thoughtful questions. As well as trying to get across what we do in industry and the rewarding careers from STEM subjects, it is an opportunity to speak directly to teachers about what can be quite limited in the curriculum on science and engineering. In some sessions, explaining what we in industry think is obvious can, when seen through different eyes, put a whole new perspective on things, so it is not just a one-way street. The practical sessions show the children the scale of our operations and seeing their sense of wonder reminds me of my primary school teacher who inspired me into my career (he was a nuclear physicist!). I would recommend anyone in STEM careers getting involved as it is a rewarding session.”

If you would like help to get cracking with your STEM education why don't you contact ciec@york.ac.uk to see if you could become involved in any of our initiatives to link schools with science based industries.  Alternatively, you could try this activity with your class as full teacher notes are available for free from our website.

Full activity notes are available in this free CIEC resource including teacher guidance and safety advice

Potatoes to plastic: Cross curricular opportunities

In the third and final post in this series linked to CIEC's latest free resource Potatoes to plastic, Jane Winter explains how it can be used to make meaningful cross curricular links.

The OFSTED report, Maintaining Curiosity, confirmed what experienced teachers already knew, it can be beneficial to both subjects when meaningful cross curricular links are made. However, it is important to do this in a way that values both subjects rather than using one as little more than a vehicle for the other.  In English lessons the teacher should be concentrating on English learning objectives and in science upon science learning objectives. One of my pet hates is when schools, with the very best of intentions, insist that writing has to be as good in other subjects as it is in English. We don't need Vygotsky's zone of proximal development theory to tell us that children are able to do more with support than they are able to do independently. The level of writing in an English lesson is achieved because of skilled teacher support which is not available in a lesson where the teacher's energy is focused on other skills.  Having said that, I have seen great writing about science which has been done in a subsequent English lesson, the children's writing benefiting from an inspirational science experience.

It is important to give children the support that they might need with English during science lessons, but this should not be at the expense of good quality science teaching.

With the value of cross curricular approaches in mind Potatoes to plastic has suggestions for a series of lessons which can be used for English teaching.  They are designed so that the teacher concentrates upon the English learning objectives, and is not trying to juggle too many plates at once.  However, the content is likely to raise children's science capital as it is based upon the biographies of six of the scientists currently working in the award winning Green Chemistry department at the University of York.  Although the focus of the lesson is on reading and writing children learn about the range of exciting jobs that the scientists do, and also find out that scientists are 'normal' people, just like you or I with families and hobbies beyond science.

When reading about real scientists in an English lesson children learn that scientists are normal people with a range of activities and hobbies, from making lego models with their children to enjoying skiing.

The final section of this free publication concentrates upon the range of other solutions to the problem of waste that scientists have developed, from extracting citronella from orange peel to turning cocoa husks into paper bags.  There are a set of downloadable playing cards which can be used for a range of games including 'Memory pairs', 'Old Fossil' and 'Go Recycle' which highlight science solutions to environmental problems.  These could be used as an activity during a science or environmental day.  Alternatively, the link and game instructions could be shared with families so that the cards could be used at home.

The previous two blog posts in this series are still available.  You can find the one about extracting starch from potato peel here, and the one about making bio-plastic from potato peel here.  If you use any of the activities we would love to hear how you get on.  It is feedback from teachers like you that helps us to know what we are doing right and how we can get even better in the future!  

Full instructions for the English activities and the card games as well as how to turn potato peel into bio-plastic are included in this free to download publication

This is what one teacher had to say after using this resource with their class.

Our current topic is all about Endangered Species and a large part of this has been around the dangers of plastics in the oceans and different habitats; so this lesson in particular was a great experience for cross-curricular discussions, the content of which were deep and enriched. In addition to this, the vocabulary resources that accompanied the investigation were a fantastic tool to help deepen the children's understanding and allowed them to speak freely, scientifically and accurately about the processes they were undertaking. Both pupil and teacher thoroughly enjoyed the lesson.

 

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.

Potatoes to plastic: Extracting starch from potato peel

This is the first in a series of three posts which have been written by one of our advisory teachers, Jane Winter.  They are based upon our latest free resource: Potatoes to Plastic

Frequently, scientists are the bearer of bad news.  Every day we read about mounting evidence of climate change, loss of bio-diversity and the prevalence of micro-plastics in the ocean. However, did you know that as well as identifying environmental problems scientists are able to develop solutions to some of them?  The world leading Centre of Excellence in Green Chemistry where scientists work on finding new ways to overcome ecological issues is based at the University of York.

CIEC has been working with some of the scientists from Green Chemistry to develop our latest resource, Potatoes to Plastic which looks at how scientists have been able to develop useful products from a range of waste materials which might otherwise go to landfill.  As well as looking at several examples of this scientific approach to environmental problems, this free publication looks at one example, making bio-plastic from potato peel, in more depth.  Teachers are supported to carry out some straight forward activities with their class which link closely to the materials strand of the KS2 science program of study.  They extract starch from a waste product, potato peel, and then turn that starch into plastic.

Extracting starch from potato peel does not require a lot of expensive equipment. 

I have found the raw material for this activity easy to source.  Although not all chip shops peel their own potatoes, once you find one that does they will almost certainly be prepared to let you have the peel for free. Alternatively, you may find that your school dinner provider is able to give you some.  Another possibility is to use wrinkly old potatoes that have started to sprout and which might otherwise have been thrown away.

Blending the potato peel with water

First of all you will need to blend the peel and a generous quantity of water in a food processor or blender. Give each pair of children a small jug full of the mixture each.  They will need to filter the peel and water mixture by squeezing it through the foot of an old pair of tights or pop socks.  This will produce a white liquid which is a mixture of potato starch and water.  The rest of the solids are left behind and can be disposed of on a compost heap.

Pouring the blended potato peel and water into a pop sock.

After a few minutes the potato starch will start to settle at the bottom of the container.  Once this has happened the water can be poured carefully off to leave behind the wet starch.  At this point children will be amazed to find that they are left with 'oobleck' which is usually made by mixing cornstarch and water.  That is because the starch found in potatoes is exactly the same as starch found in corn.  Once children have finished playing with the oobleck it will need to be left in a shallow container such as a saucer or petri dish to dry.  After a few days all of the water will have evaporated and you will be left with dried potato starch.  

In the next post I will explain how you can turn the potato starch into plastic.  However, if you cannot wait why not check out the full instructions for both activities on the website.  This includes teachers' notes, children's activity sheets and health and safety advice.  This is what one teacher who recently carried out the activity with their class had to say about it.

'Absolutely fantastic! The children have never felt so alive, enthused and engaged in a science lesson that I have taught. They absolutely loved the practical element of blending the potatoes, filtering the starch and using interesting 'ingredients' to create the plastic. Their scientific skills were so clear and they were all extremely careful in measuring their resources and ensuring the investigation plan was carefully followed. The time taken for the excess water to evaporate and leave the powdered starch behind kept them even more engaged as they spoke about nothing for days until it was ready to use'.

Water for Industry: Leaky pipes

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

I have always been a massive fan of teaching outdoors; children are more engaged and motivated and, in my experience, behaviour is much better.  The noise is less intense when not trapped by four walls and, much to the caretaker’s joy, any mess is in the playground instead of on the carpet.  In the current pandemic there is the added benefit of less risk of transmission of Covid-19.  The first half of the autumn term is a particularly good time to use your outdoor space as the weather tends to be at its best; no need for sunscreen or too many outer layers either.

Top tip: Make sure that families know that you will be regularly teaching outdoors and ask them to provide suitable warm clothing.  It may be worth having a supply of spare jumpers and coats (ask for donations of outgrown ones) so that one or two cold children don’t scupper the lesson for everyone.

Although today’s activity can be carried out indoors, it also works very well outside as the equipment is sturdy enough not to be blown away if it is windy.  Moreover, instead of mopping up any spills you can just leave them to evaporate.  This activity is cheap to resource and uses empty food cans which you could ask children to bring from home, although you will need to double check that there are no sharp edges and that the cans have been thoroughly cleaned.  If they have not been adequately sanitised they will also need quarantining for 72 hours.

Full details of the activity, including list of equipment and safety advice can be found in our free resource Water for Industry

The children are asked to test different potential sealants to see which is the best for connecting pipes and preventing leaks.  This is an engaging way for children to work on the Y5 objective ‘give reasons, based on evidence, for the particular use of everyday materials’.  Equally it could be adapted for use with Y2 children who need to ‘identify the suitability of a variety of everyday materials for particular uses’. The activity also gives children the opportunity to practice accurate measuring and making graphs.  Asking them to report their findings to a pipe-line company provides extra motivation and would be a novel way for children to record their findings.

Our Leaky Pipes IndusTRY AT HOME activity is ideal for you to share with families. Why don’t you put a link on your school website?

Kitchen Concoctions: The Best Bubbles

Children from Ysgol-y-Lys primary school in Wales gather to see which group of young scientists has developed the best bubble mixture

The first time I came across this activity I was still teaching full time and was attending a course run by my now colleague, Nicky Waller.  I am not going to lie to you, I had much more fun than a middle aged lady should be having with some washing up liquid and a bubble wand!  We had been challenged to investigate the proportions of three ingredients (washing up liquid, glycerine and water) to develop an economical bubble mixture that would make the ‘best’ bubbles, and I was determined that my team would ‘win’.

Top Tips: If you ask people to find a mixture that produces the ‘best’ bubbles without giving any more guidance, it is likely to lead to some interesting discussion.  After a while they will realise that they need to think about what is meant by best; it could be the size or the quantity of the bubbles or how long they last for example.

Deciding how they are going to measure bubble size is yet another challenge – my favourite that I have seen children chose over the years being … popping the bubbles on sugar paper, which leaves a lovely measurable ring!

I have delivered the session myself many times in the intervening years both as a primary teacher and in my current role.  I have run it with various groups including groups of teachers, parents and with children from nursery through to year 6, including in mixed age groups.It never fails; participants are always fully engaged and, if approached carefully, there is a high degree of relevant discussion and science learning.

Full details of the activity, including teacher notes, risk assessments and activity sheets can be found in our free resource Kitchen Concoctions

Because it can be done in mixed age groups, works well outside and is cheap enough to provide enough resources for each child to have their own equipment this activity could easily be adapted for socially distanced circumstances.  However, it does need to be approached thoughtfully if it is to move beyond being  more than ‘a fun thing to do’.  Having said that, it is also important not to move children too quickly to formally measuring and recording their recipes as they benefit from an initial period of play, exploration and discussion before formulating their method.

The challenge of devising an economic yet effective bubble mixture for a ‘toy manufacturer’ is an engaging start to this activity.  The poster is provided as part of the free online resource.

Top Tip: Do give children small containers to work with as this forces them to produce smaller quantities of bubble mixture.  I know from bitter experience that larger containers will lead to them using industrial quantities of washing up liquid!

After the initial exploratory phase, children work together to work out the ratio of ingredients that produces the ‘best’ bubbles, while keeping the costs of ingredients as low as possible (there are lots of opportunities for the application of maths at this point).  It can be tempting to organise children to work efficiently, and difficult to give children space to make their own mistakes and ‘muddle along’; for a conscientious teacher this can feel as if you are not doing your job properly.  I find that making a few explicit notes on my planning helps me to feel better about this ‘hands off’ approach.

For teachers brave enough to take this approach and then allow time afterwards for a discussion to evaluate how they worked the learning opportunities are immense, especially if there is time for children to repeat the activity.  At this stage I used to add an extra level of challenge by providing more than one brand of washing up liquid (preferably in different colours; not all washing up liquids are green).

Developing an effective product and reporting the results is engaging for participants of all ages, and helps them to understand the diversity of science related careers.  This helps to raise children's  science capital.

Children will need to find ways to present their findings to the toy manufacturer that set the challenge and this will inevitably lead to further discussion and the opportunity to use their literacy skills, and maths too if they decide to use a table and include costings.  I find that enthusiasm is maintained throughout in a way that doesn’t always happen with many other ways of recording science as children have a real reason to share their results.  If your children send their report to ciec@york.ac.uk they will be delighted to receive a reply from the ‘toy company’ that set the challenge.

This is a great activity to share with families so why not provide a link to our IndusTRY AT HOME page on your school website?

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

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!

Sustainable materials: which metal?

Full details of the activity can be found in the new CIEC publication 'Sustainable Stories and Solutions for our Planet' which can be downloaded from  http://www.ciec.org.uk/resources/sustainability.html

Sustainable materials – which metal?

In this activity you will investigate how some metals rust when exposed to oxygen in the air and water. You will learn about some metals that do not change, corrode or rust easily and so have special uses, particularly in reducing gas emissions on highly polluted roads.

It would be a wonderful way to teach the ‘Properties and changes of materials’ strand of the science curriculum for Year 5, with a particular focus on how some changes result in the formation of new materials that is not usually reversible.

The Activity: 

·         Carry out a ‘rust hunt’ to observe how some metals change colour and become weaker (corrode) when they react to substances in the environment.

 ·         Investigate which metals rust by placing everyday metal objects in saucers of shallow water. Over several days, observe which objects start to show signs of rust and which do not. Steel wool pads can be used to test for signs of rusting.

·         Begin to form conclusions about which metals rust and what causes this to happen. You could use a magnet to identify metal items that contain iron or steel.

·         Think of your own ‘rusting’ enquiry questions, such as: can iron or steel rust when there is no water? Does salt speed up rusting? Can I prevent rusting? Plan and carry out your investigation; you can ask for extra ‘kit’ if you need it.

Results from rusting activity using a steel wool pad left for two days in different liquids.

·         Research how some metals, such as gold, silver, platinum and palladium, are unique because they do not react easily, change or corrode. These ‘precious metals’ are often used to make jewellery as well as catalysts which are fitted to car exhaust systems to turn harmful gases produced in the engine into safe gases. 

Links to the National Curriculum

Y5 Properties and changes of materials:

• explain that some changes result in the formation of new materials, and that this kind of change is not usually reversible, including changes associated with burning and the action of acid on bicarbonate of soda.

Working scientifically:

• planning different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary
• recording data and results of increasing complexity using scientific diagrams and labels, classification keys, tables, scatter graphs, bar and line graphs 
• reporting and presenting findings from enquiries, including conclusions, causal relationships and explanations of and degree of trust in results, in oral and written forms such as displays and other presentations  

Cough Syrup: Thinking like a scientist

Full details of the activity can be found in the CIEC publication 'Cough Syrup' which can be downloaded from  http://www.ciec.org.uk/pdfs/resources/cough-syrup.pdf

This publication contains lots of opportunities for children to think and work like a scientist and learn about the different stages in the production of a new medicine. It would be a wonderful way to teach the ‘Properties and changes of materials’ strand of the science curriculum for Year 5, and then extend the topic as well as the full range of enquiry skills with Year 6.  Teachers may choose to approach this lesson in two different ways.  Children can follow fairly prescriptive instructions which give teachers the opportunity to teach and assess skills such as measuring and graphing and the importance of repeat measurements.  Alternatively, teachers can teach and assess children’s skills to plan, carry out and evaluate a fair test by offering children the opportunity to devise and carry out their own investigation.

The Activity: Filtration

• In the lesson prior to this, children investigate the most effective method of producing the active ingredient for a new cough syrup. They test different conditions for growing yeast.
• In this activity, children are reminded that the active ingredient is a micro-organism which is living in a liquid (growth solution) and they are challenged to suggest ways of getting the active ingredient out of the liquid. 
• After a class discussion about different methods, children think about how to test different materials as filters. They use a mixture of flour and water to represent the micro-organism and growth solution. 
• Groups might work together to devise a fair test. If using this approach they may find the interactive planning tool a useful resource.  Alternatively, each group could be asked to test four different materials to find the most effective filter. In this case, they should place their first chosen material in a funnel or upturned bottle and hold it over a beaker to collect the water. They should stir and then pour 100ml of their flour and water suspension through the filter and time how long it takes to collect 50ml of the liquid that comes through. 
• If following instructions, children should repeat this for each of the filters, mixing a new suspension each time. 
• Throughout the investigation, children would then compare the times taken as well as the clarity of the filtrate. This may be done by straightforward observation or by placing the filtrate in front of a dark background, shining torch light through the liquid and placing them in order of clarity. Light sensors may also be used for increased accuracy and to produce quantifiable results that can be presented in a bar chart or, if comparing time and clarity, a scatter graph. 

• If children have devised their own test, do not be afraid to let them spend time on activities that you know will not work. Also, allow plenty of time at the end of the lesson to discuss and evaluate the methods that they chose.  This allows for much deeper learning than if they are guided towards a more ‘successful’ test in the first instance.
• The results of the filtration tests should be reported back to a real or fictitious medicine company and suggestions made about how the active ingredient can be extracted from the filtrate. 

Year 5 children carrying out the filtration activity.

Year 5 children carrying out the filtration activity.

Links to the National Curriculum

Y5 Properties and changes of materials:

• use knowledge of solids, liquids and gases to decide how mixtures might be separated, including through filtering and sieving
• demonstrate that dissolving, mixing and changes of state are reversible

Working scientifically:

• planning different kinds of scientific enquiries to answer questions, including recognising and controlling variable where necessary.
• taking measurements, using a range of scientific equipment, with increasing accuracy and precision
• recording data and results of increasing complexity using scientific diagrams and tables
• reporting and presenting findings from enquiries, including conclusions, in oral and written forms