Young Scientists at Play: Polymer Play – Making Snow

Did you know that up market nappies contain polymer balls?  They exploit the water absorbing qualities in order to absorb urine.  These are made from a similar polymer to water beads and are the chemical that is used to make fake snow.  This polymer is also used for its  water absorbing properties in gel flood bags to contain a flow of water.

I had thought to allow the children these to play with (the balls not the nappies).  There are many article expounding on the dangers of this.  And I read a few.  I also looked at the chemistry and the research (which stated they were safe, and it was only prolonged exposure inhaling it that there could be dangers).  I decided that as long as a few precautions were taken they should be perfectly safe.

  • The powder would not be breathed in as I would do the handling of the dry powder inside a ziplock bag. Once water was added this would cease to be an issue.
  • The powder would not come in contact with the skin at all, as the children would be wearing protective equipment
  • I would teach them about the potential dangers of handling this chemical and how to minimise them

I emptied two nappies, shook out the balls, all within the confines of a ziplock, removed the bulky material, and was left with 4 tsp of tiny white balls.  I placed 1/2 tsp into their test tubes and instructed them not to touch.  They were given gloves, and as always wore their goggles.  As they were going to immediately add water and would not be in contact at all with the powder, I felt they were safe without any face mask.  I let each child add some coloured water and stir, and explore for as long as it held their interest.

Their tray was set with goggles, gloves (and elastic bands to keep them on), large test tube with polymer powder in, small test tube with coloured water, pipette and something to stir with:

And off they went
And off they went
A4 so enjoys science and loves exploring anything I put in front of her
A4 so enjoys science and loves exploring anything I put in front of her
She enjoyed seeing the water turn from liquid to solid
She enjoyed seeing the water turn from liquid to solid
And asked if she could pour it out into her tray to play with
And asked if she could pour it out into her tray to play with

The older children joined in.  They had loved the water beads so I asked them to think of another use for them other than just to water plants.  The night before I had rehydrated some of the nappy polymer and they had commented that it looked like snow, so T11 said to make fake snow.  Nobody guessed that they were used in nappies or to prevent flood water.  I asked them to put a teaspoon of polymer powder into a pot and then to record how many teaspoons of water it would take to liquefy.  They set up their trays something like this:

Large jug with polymer powder, conical flask of water, teaspoon, gloves and stirrer.  They also had paper and pen and used tally charts to count.
Large jug with polymer powder, conical flask of water, teaspoon, gloves and stirrer. They also had paper and pen and used tally charts to count.
The powder absorbed the water and much more was needed than the children first thought.
The powder absorbed the water and much more was needed than the children first thought.
In fact, the powder took in 100 times its volume in water, and increased in size considerably.  The powder shown here is of a wet snow consistency and the children could have added a lot more water before reaching true liquidity.  However they chose to stop at 100 tsp
In fact, the powder took in 100 times its volume in water, and increased in size considerably. The powder shown here is of a wet snow consistency and the children could have added a lot more water before reaching true liquidity. However they chose to stop at 100 tsp

So the polymer powder in the nappies took in 100 times their own volume before they became even slightly wet!  I asked the children what the advantages and the disadvantages were of the polymer being used in nappies.  T11 commented about the bulk when the polymer expanded, L10 made the comment about urine being left near to the skin, C10 said the nappies wouldn’t leak and would need to be changed less frequently.  I asked if this was an advantage or disadvantage.  They discussed it and came to the conclusion it would be an advantage for the parents but maybe not for the baby.  I also had them consider the potential dangers for the baby.  We discussed the use of a one way semi permeable membrane built into the nappy, protecting the baby’s skin.  Also I told them what I had learnt when I took the nappy apart- that the balls were in the back of the nappy with a wad of cotton next to the baby’s bottom.

Interestingly, it was the expensive brands which contained the most polymer powder, whereas the cheap brands had hardly any at all.  I learn something new everyday!

  Science Sunday

13 comments

  1. Interesting that they reached that conclusion about the extended time between diaper changes. It’s great to see that they are really “absorbing” the information! (Sorry, couldn’t resist.)

  2. Here is something else new – It is my husband’s brother, in the USA, who was the or one of the scientists who “discovered” the use of the polymer for diapers (nappies) for the Pampers brand. He also found many more uses for the polymer. That was his area of work.

    Myra, from Winnipeg, where we will have another beautiful sunny day.

      1. I know that it is used in feminine hygiene products, in a product used in gardening that is mixed into the soil to retain moisture, by florists (a “bead” compound that is mixed in with the water to help the flowers last longer), and something in concrete or street paving but I cannot remember what.

        Myra, from Winnipeg, where the g’kids are busy outdoors after a shortened school session

  3. Waaaaaay back when Princess was still in diapers I did this with the kiddos, but I didn’t use as many safety precautions. I didn’t give them access to the stuff until it was wet though, so that removed the inhaling danger.
    I read somewhere ages ago, so don’t hold me to this, but the polymers in the diapers are also used to help “defuse” hurricanes by removing some of the moisture out of the storm. I don’t know quite how it works, because at the time I just thought interesting factoid, not “cool thing to teach kids later.”

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