An invitation to experiment


An invitations to play is essentially leaving a set of materials out for your children to explore. I really love how children can learn so much through play – particularly child led play. As Chair of our local Pre-School I learned a lot more about this and why it is important – from helping to build confidence to developing problem solving skills. Read on for some ideas on putting together a science experiment with more of a child led approach in mind.


What you will need…

  • Bicarbonate of Soda
  • White Vinegar
  • Food colouring or liquid water colours
  • Washing up liquid
  • Various containers to hold your potions (for one of the experiments you will need a container with a lid that is able to pop off. This is tricky to find I know – luckily we had a test tube from Grace’s science party. But something like a Berocca container would be ideal. If you haven’t got this to hand don’t let it stop you – the rest is still fun! There is a link to buying test tubes at the bottom too.)
  • Measuring spoons and jugs (great for talking about math concepts through play)
  • Goggles and a magnifying glass (because they are fun – the goggles are adult ones from the DIY shop for £1.40)
  • A pen and paper if you would like to record the experiments (I did but the girls just wanted to get into the experiments today!)

Firstly, a true child led session would have lots of activities out and the children would self choose. But this is the real world – at home – and they wanted to do an experiment so I foraged some stuff from the cupboards and we went from there!

I showed them the ingredients and together we decided we wanted to look at mixing the bicarbonate with the vinegar. It fizzed! We already knew that, having done it lots before, but it is so much fun.


The key to a child led approach is letting the children decide what to do next and you need to ask open ended questions (all my questions are in italics). For example…What would you like to do? How much shall we mix? What do you think will happen? They will want to know why a reaction happens so be prepared with the answers or have google to hand! We then decided to add colour.


I asked them if adding colour changed the effect. No, but it looked pretty! Asking them to describe the effects in detail, listening and discussing it with them is fun and important. You can almost feel them making connections in their brains! Their confidence is also blossoming as Mummy is really listening and discussing their thoughts (rather than just trying to have a quiet, sneaky cup of tea!)


We then added different colours. Did this change the effect – no – and they were not as pretty as the first colours! We talked about why it was fizzing too – essentially the vinegar is an acid. It reacts with the bicarbonate of soda (a base) and forms carbonic acid. Carbonic acid is not stable and it decomposes almost immediately into water and carbon dioxide gas – this is what causes the bubbles. The same bubbles are in fizzy drinks and carbonic acid is what gives it that slightly acidic (fizzy) taste. That explanation led to a lot of questions on decomposing, acids and gases! (apologies to all you scientists out there for that basic explanation!) Mm…what would happen if we added soap?


Hurray bubbles! But not pretty enough…colour is needed!


What happens if we add lots of vinegar? Cool – lots of fizz – a quick and fast reaction! What happens if we add bicarb on top? Not so exciting. Why? An even distribution of all the ingredients is needed or the gas is quickly lost into the air (the fizz fizzles out) rather than the gas having to make its way out through the bubble mixture – blowing the bubbles up first (useful knowledge for later on as it turn out). Cue discussion of how cakes rise….


What happens if we change the shape of the container? Will it have a more exciting effect? Oh yes!


They decided on the order of the ingredients – colour, bicarb, bubbles liquid and then in with the vinegar.


Later on we ran one set of tubes with the ingredients in different orders and looked at the effects (but I forgot to take a picture as we were so involved at that point!). Child led is important but this is where a carefully placed open ended question can be invaluable as the girls had not thought about this step. What do you think will happen if we put the ingredients in a different order? Shall we test them all together? We think bicarb on the bottom, fairy liquid, then colour is the best!

Another carefully placed question to finish off – We know that the chemical reaction is producing carbon dioxide gas – what will happen if we trap the gas in a really small space? How can we do this? (cue carefully placed container with lid!)


What is going to happen…is this safe mummy? (my youngest thought not as she hid behind a wall!)


It explodes! We repeated this at least 10 times and it was just as exciting each time (well, for Grace – although she didn’t want to hold it – Kitty had wandered off for the last few!). There was a lot of vinegar on our ceiling when we had finished! You can just see the yellow lid pop off! We were able to take this picture as we managed to slow the reaction down slightly by adding bubble mixture on top of the bicarb (our previous learning came in handy!). Without the bubble mixture on top it is barely possible to get the lid onto such a small container.


Enid Blyton Rating: 10 out of 10 (Messy but fun and so exciting to let the girls develop their own experiments)

P.S. The test tubes and droppers are from here and are fairly inexpensive – they are worth investing in to really bring science to life! I also found some really nice huge glass test tubes and flask from there which were used in Sherlock! They are now a funny vase and a funky wine decanter!


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