Scientific Sue returns to the Bord Bia’s Bloom in the Park Festival

Bloom 2013, Ireland’s largest gardening, food and family event,  is taking place in the Phoenix Park Dublin over the June bank holiday weekend, from Thursday 30th May until Monday 3rd June 2013 and once again I am sharing the stage with Billy Bubbles or the  more formerly known Brendan.

We have been so blessed this year with glorious weather… which magically correlates to mega loads of visitors who are all happy and smiling; last year was so wet and cold – however this didn’t keep visitors away I think over 80000 people came through the gates last year, but this year I am aware of many more children and those that come through the gates stay for nearly the whole day.

All of the acts onthe stage last for around 30 minutes. I am always precede by Brendan who performs 15 minutes of very funny magic which is followed by one of the best Punch and Judy Shows I have ever seen… The children squeal with delight!

To fit in with the Magic theme I have added a little bit of magic to my science show; and the magic relates very closely to the Bloom festival itself and I call it the disappearing water trick!

Disappearing Water Trick

Before we do this trick we have to collect the off white crystals found in babies nappies!  Using scissors cut around the outside of a nappy and place the middle section into a large Ziploc bag.  Carefully separate the layers then seal the bag.  Shake for about 1 minute; you should see the crystals start to collect in the corners of the bag.  Slowly open the bag; bin the large pieces of material and the fluffy fibres. Store the granules in an airtight container.  Wash your hands.  The chemical name for these crystals is sodium polyacrylate – or as I explain in the show after one of my brave volunteers has had horses’ pee poured over their hands (!) the crystals are not only found in nappies they are  exactly the same crystals  used by gardeners and can be bought  from a garden centre or large supermarkets. The crystals are sometimes called water loc or super gel.  These crystals can magically (and rapidly) absorb 500 -1000 times their mass in water! They also release the water slowly which is why they are often used in outdoor potted plants and hanging baskets… and by the way the Hanging Basket displays along the walled garden at Bloom (Phoenix Park) are just mind blowingly huge and beautiful. I wonder if they are for sale at the end of the show?? Hmm

Safety Notes:  If collecting crystals from nappies the shaking must be done with the nappy placed inside a sealed plastic bag as if inhaled sodium polyacrylate can irritate the nasal membrane.  Avoid eye contact by wearing safety glasses; if it gets into eyes they will become dry and irritated.  Be sure to always wash your hands after handling this chemical.  Dispose of the crystals in a bin.

Nuts & Bolts

3 polystyrene cups (or mugs which are white inside)

1 teaspoon of sodium polyacrylate crystals

Jug of water (or bottle of pretend pee … oh did your really think I used horse’s pee? lol)

Hoberman Sphere

Secrets for Success

Place the granules in one of the cups; pour in a small amount of water to ‘set’ the gel.  Do this away from your audiences’ eyes; but just a few minutes before you do the trick. Turn the 3 cups upside down on the table. With your audience in front of you turn the cups the right way up very quickly showing them the insides of the cups – the gel doesn’t show up against the white background.  Now pour in about 10-20 ml of water.  Move the cups about on the table and ask your audience to guess which cup the water is in.  Let them know that whichever cup they choose you will turn up-side down over your head… but if they choose the wrong cup you should be allowed to throw the water over one of their heads!!! Fair’s fair.

They will obvious choose the right cup and will be amazed to find that it is empty.  They will very quickly then get agitated as they realise that one of them may get a soaking!!  After all of the drama and the realisation that all of the cups seem to be empty – some may shout out that you have a sponge or tissue in the cup – these choices would in-fact absorb the water but because they are not sticky they will fall out of the cups if turned up-side down.  Put your fingers into the cup with the gel; scoop some up and let them see it.  Make sure you wash your hands afterwards – or wear disposable gloves.

Science in a Nutshell

Sodium polyacrylate is a polymer; ‘poly’ means many and ‘mer’ is a unit of something, in chemistry this is usually a molecule – so polymer literally means long chain of molecules.  The sodium polyacrylate crystals soak up water using the process of osmosis (water molecules pass through a barrier from one side to the other).  The polymer chains have an elastic quality; but there is a limit to the amount they can stretch and hence a limit to the amount of water they can hold.

One of the greatest uses of sodium polyacrylate is in making nappies super-absorbent.  Table salt (NaCl) destroys the gel and releases the water.  How??  No one knows – so if you want to make a name for yourself why not study the chemistry of this compound and become the next science superstar!

Polymers, long chains of chemicals, are found everywhere in nature; proteins are polymers. These are found for example in hair, feathers and cartilage.  Cellulose is also a polymer which is found in wood, leaves and other plant parts.  Polymers can also be made by man; plastic and nylon are good examples of manmade polymers.

Going Further

Try the following experiments: How much water will a Pampers’ nappy hold?  How do other brands of nappies compare?  How much water does a teaspoon of sodium polyacrylate hold?

Just realising a good photo is required for this article so my mission tomorrow is to get one!