Fun with Sugar cubes

We have looked at how objects absorb water before. Today we are taking this a step further and trying to halt the process, and so investigate which materials are good absorbers and which are not. We’re going to do this with a fun and very simple absorbing experiment.

Absorbing experiment

What you need:

  • Sugar cubes
  • Plate
  • Water
  • Food colouring
  • Aluminium foil
  • Cling film
  • paper
  • kitchen roll


Add a few drops of food colouring to some water and pour onto the plate.

Add a stack of sugar cubes and observe what happens. The coloured water should move up the stack of cubes and eventually make them collapse.

Try adding a small sheet of foil on top of one sugar cube and stack some more on top. Does this stop the water reaching the top cubes?

Absorbing experiment

Try the same with some cling film, and some paper or tissue. Which work the best?

Absorbing experiment

Which falls down first?


The Science Bit

The water is absorbed by the sugar cubes as you can see by the colour rising up through the cubes.Our foil and cling film did stop the flow of water for a while, but eventually it found a way through. I think we cut the foil/clingfilm a little small. These were the last stacks to fall though. The paper absorbed the water easily and let it reach the cubes above. This is because paper is porous and lets water pass through it. The foil and clingfilm prevent water passing through.

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There are 21 comments

    1. Niamh Bevan

      I’m sure the children loved watching the whole process but I’d be extremely interested to know how many 5 year olds were able to manage figuring out the cause for the sugar melting at different paces. It is within their grasp as I’m sure they’ve all handled kitchen paper, foil and cling film. Lots of children that age are smart enough to figure it out in those circumstances.

      1. ScienceSparks

        My main aim with these investigations is to spark an interest in why things happen. I’m not necessarily all that bothered that my children understand fully the reasons behind it. I just want them to be curious about the world.

  1. mom is the only girl

    I like this idea! I was going to do the paper towel absorption experiment later today, now maybe I’ll do both!

  2. heather at wordplayhouse®

    The sugar cubes are ideal for your experiment! The water absorbing shows so clearly for children, and it adds a little bit of fun to the science experimenting that you are using both sugar and color—2 things children really seem to love!

  3. lis

    the problem I encountered is that with most of the materials I tried, the bottom sugar cube collapsed well before the top cube got any moisture in it at all. so I turned the experiment upside down–stack two sugar cubes, lay a piece of plastic/foil/paper/fabric/whatever on top, then use an eyedropper to put water on top. this worked much better.

  4. Amy

    How long does this experiment take? I only have one hour with my kids and was wondering if the water will make it through the sugar by then.

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