Showing posts with label mixtures. Show all posts
Showing posts with label mixtures. Show all posts

Monday, December 5, 2022

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.

Tuesday, July 7, 2020

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.



Wednesday, January 23, 2019

Science of Healthy Skin: Investigating what happens when oil is added to water

Full details of the activity can be found in the CIEC resource 'Science of Healthy Skin’ which can be downloaded from: http://www.ciec.org.uk/resources/science-of-healthy-skin.html
Based upon the extraction of lanolin from wool grease, the activities in this resource include testing immiscible liquids using oil and water and investigating the effects of adding detergent to produce emulsions which in turn reduce the efficiency of the separation of oil from water.

The Activity: Fleece to Grease

Resources 

  • 300 ml water
  • 300 ml sunflower oil
  • 50 ml clear water - sample A
  • 50ml clear glycerine - sample B
  • 50 ml clear detergent - sample C
  • 50 ml white vinegar - sample D
  • 4 clear plastic mini pop bottles or lidded containers around 30ml per group of 4 children
  • Pipette x 1 for each child
  • Teaspoon or similar for stirring
  • 100 ml measuring cylinder 


Objectives

  • To describe changes that occur when materials are mixed
  • To make systematic observations and measurements
  • To know that that some liquids do not mix, can be separated easily and are termed ‘immiscible’
  • To observe that detergent can cause immiscible liquids to mix, producing an emulsion

What happens when oil is added to water?

Each child in the team of 4 to pour 10ml of water and 10ml of oil into one of the containers.
Ask them to wait for 1 minute to see what happens to the oil and water.
Tip the containers upside down four times and ask the children .....
  • Did the oil and water mix?
  • Did shaking make the liquids mix?
  • Why do you think this happened?

The oil and mixture quickly separate when they are on their own.  But will adding any of the other ingredients make a difference?



Investigate whether adding sample A, B, C or D affects the separation of water and oil.

Using the pipette, add 10 drops of sample A to one of the bottles, 10 drops of sample, B to another bottle and 10 drops of samples C and D to the other two bottles.
Ask children to observe how long it takes for the oil and water to separate after 4 shakes.
Ask them to consider how they will record their observations.



Health and Safety
Remind the children not to drink their samples.

  • planning different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary
  • Taking measurements, using a range of scientific equipment, with increasing accuracy and precision, taking repeat readings when appropriate
  • Use observations, measurements or other data to draw conclusions

Subject Knowledge

Learning Objectives
  • Know that changes occur when materials are mixed and some of these are reversible


Monday, December 10, 2018

Cough Syrup: Investigating viscosity



Full details of the activity can be found in the free CIEC resource Cough Syrup which can be down loaded from  http://www.ciec.org.uk/resources/cough-syrup.html

T
he activities in this resource look at the way a new cough syrup can be developed. Children work to identify the best conditions for growing micro-organisms to produce the active ingredient in the medicine, the best way to collect it, and the ideal consistency for the syrup. Economic and commercial factors are also considered. The activity described here invites children to investigate the effect of altering the ratios of specific ingredients on the viscosity of the resulting syrups. The aim is to find the best consistency for a cough medicine.

The Activity: Viscosity Testing

Resources
  • Activity sheet 5 (1 per child, optional)
  • 50 ml liquid glucose (available from most supermarkets or pharmacists)
  • 50 ml glycerine
  • 50 ml water
  • 20 ml measuring cylinder                                                                  
  • Small containers                                                                                           
  • Plastic spoons or stirrers
  • Measuring spoons
  • Pipettes
  • Blank sticky labels


  For the viscosity testing (depending on the test chosen)
  • 3-4 marbles
  • 1 plastic funnel
  • 1 stop clock
  • 1 30 cm length of dowel marked in centimetres
  • 1 30 x 20 cm board (or other smooth surface)



Instructions
  • Begin the lesson by discussing the meaning of ‘viscosity’ with the children and explain that it is the scientific term used to describe the ‘runniness’ of a liquid. Encourage discussion about how runny a medicine would need to be, based on the children’s own experience. 
  • Show children the three ingredients that could be used to produce a syrup to carry the active ingredient in the medicine they are producing: liquid glucose, glycerine and water.
  • Next, ask the children to explain why, in a commercial environment, it is vital that a recipe is systematically recorded and reproduced so that it is identical each time? Is it important to accurately measure and record the amounts of the liquids used?  How can we ensure that the runniness is the same.
  • Ask the children how they are going to measure the viscosity of the cough syrup samples they make. Show the children the equipment listed above and get them to work in groups to think which items could be used to test viscosity (e.g. timing a marble sinking through liquid).
  • Once they have decided on a way to test viscosity the children can now begin their investigation. Encourage them to use different proportions, combinations and ratios of liquids (a total of 50 ml of any of the liquids combined is enough to obtain results).  Once a sample has been tested and recorded it can be changed to dilute or thicken and then retested provided the changes are recorded.
  • Ask the children to explain results, which combination do you think would make the best cough mixture?   Explain your conclusion. 
  • Ask the children to think about whether their tests were fair, their results reliable and whether there are any improvements that they could make to their tests.



Tip
  • Link this activity to the subject of ratio in maths.
  • Discuss the use of glucose in the recipe and the fact that sugar in medicines and food stuffs is bad for our health.




Health and Safety
  • Remind the children not to drink their samples.





  • planning different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary
  • Making measurements, using a range of scientific equipment, with increasing accuracy and precision, taking repeat readings when appropriate
  • Use observations, measurements or other data to draw conclusions

Subject Knowledge

Learning Objectives
  • Know that changes occur when materials are mixed