Soap Clouds and Clean Mud

A really fascinating science experiment which we managed to convert into two messy play activities and a whole 2 hours of fun! With just two ingredients we made a soap cloud, soap snow and then ‘clean mud’. However you do need a particular brand of soap to make it work…


Simply take…

The ‘Soap Cloud’ experiment:

  • 2 x bars of Ivory Soap (you will want to do the microwave bit twice and you can make it all into ‘clean mud’ later or you can just use the enormous clouds for bath time if your children don’t have really sensitive skin)
  • 1 x bar of any other soap
  • 2 glasses of water
  • A microwave for the ‘soap cloud’ experiment (to make the ‘clean mud’ recipe below without a microwave just grate the soap)

To make ‘clean mud’:

  • 2 x rolls of toilet paper
  • Cup and a half of water
  • Shallow tub to hold it all

The ‘Soap Cloud’ Experiment

I popped the soap next to two glasses of water and asked the girls to make a hypothesis (it is great to use scientific words at home even when they are small…hopefully giving them confidence later on in science at school). Will the soap float or sink? Given that the soap weighs the same…will they act the same? We always lose the soap in the bottom of the bath so a very definite –  they will both sink!


No they don’t…one sinks and the bar of Ivory soap floats…despite the fact they both weigh the same.  IMG_4168

Hmm interesting what else will this soap do? Lets microwave it! I grabbed a chair for the children so they could see what was going on in the microwave. We put the bar of soap on a plate. Popped the microwave on high for 2 minutes and watched as the soap magically began to expand into a ‘cloud’! Ours did not take the full 2 minutes and I stopped it when it looked like it had stopped expanding. Take it out, let it cool for 30 seconds, and touch it. It feels fairly rigid but looks like a fluffy cloud (see the picture at the top of this post…you can pick the whole thing up and it stays intact!).



Ordinary soap does not do this. We did try it with the other bar and it has no reaction at all – it just warmed up – it probably would have melted if we had carried on. Steve Spangler science has an excellent explanation but essentially the soap is less dense than water. This is because Ivory is the only soap to have air pumped into it when it’s made (an accidental process discovered in 1890!).

Mr Spangler goes on to explain the reaction is similar to popcorn popping…along with the air bubbles water is present…so as the water is heated and vaporises the trapped air is heated and expands – causing the popcorn to pop and the soap to expand.

What to do with this magnificent ‘cloud’?

Touch it and break it up into snow of course! We used knives to chop it too.


Add animals and you have a lovely snowy play world…complete with blizzards!


To extent this activity further make ‘Clean Mud’!

  • Take all the paper off your toilet roll, preferably by throwing it around the place with much hilarity – always fun to make a mummy too (just unravel one roll first, you can always add in the second roll later if the mixture is to wet). Gather it all into a plastic tub and rip it up into fairly small pieces to get smoother ‘mud’.
  • Take 2 bars of ivory soap, puffed up and broken into the snowy mixture, and sprinkle into your tissue paper tub (if you don’t have a microwave just grate the soap bars instead).
  • Add a cup and a half of water to the mix and smoosh it up a bit with your hands and it will start to form moldable ‘dough’. The girls alternated between squeals of delight and cries of ‘this is horrible’ doing this! (At this point we moved it into trays on the table…a big shallow tub on the floor would work well though and we have a fantastic box from IKEA which we now put all sorts of messy things in. It also doubles as a light box).
  • Just add animals (again!) and more tissue paper if it is a little wet or if it is too dry add a little more water.
  • You will end up with a squishy, soft dough…slightly odd but very touchable.


When all the tissue paper is in you can also make it into a snowball!


Instead of animals you could add biscuit cutters and tea sets for pretend cooking fun. To make a coloured dough just add coloured water when you are adding your water initially. We quite fancy adding glitter too… Lots of fun and it leaves the kitchen with a soapy fresh smell!

Enid Blyton Rating: 9 out of 10 (Good clean fun! …Im sorry I just couldn’t help myself!)


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