Tuesday, 9 December 2014
Playing with Hydrogel
We took about 7 cm3 of hydrogel . We extracted this from a clean dry Nappy.
A disposable nappy
A large ice cream tub or similar container
Dessert spoon or similar measure
Large beaker or plastic tub to hold at least 600 cm3
Plastic gloves for those with sensitive skin
a Cut the middle section out of the nappy – the thicker piece that is designed to absorb
the urine. Discard the other piece.
b Make sure the ice cream container is completely dry - wipe it with a paper towel if
necessary. Any moisture in the tub stops the experiment from working properly.
c Wear eye protection for the next step. Put the centre piece of the nappy into the ice
cream container and gently take it apart. Small white grains should start coming away
and this is what you are trying to collect. Keep gently pulling the nappy apart until you
have collected as many of the grains as you can. Do not do this roughly or you will lose
your product and put a lot of dust and fluff into the air. Avoid breathing in any of the
d Remove and dispose of all the fluff and other parts of the nappy, keeping the grains in
the bottom of the tub. They are heavier and fall to the bottom, which makes it easier to
separate them out.
e Estimate the volume of the grains.
Now the fun Bit
f Pour them into the large beaker and add about 100 cm3 of distilled water. Stir. Keep
adding water until no more can be absorbed and stir between each addition.
Estimate the final volume of the hydrogel.
Now even more fun
g Add a dessert spoonful of salt and stir.