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Friday, October 28, 2011

Crazy Putty

On Wednesday Room 5 made crazy putty. We used some equipment that Miss Sheppard had ready on our desks.
  • 60ml PVA glue
  • 60ml water
  • 60ml of borax solution( 1 cup of warm water and 1 and a half teaspoons of borax powder)
  • measuring spoons
  • small cup
  • spoon
Firstly we measured three lots of 20ml of PVA glue with the measuring spoons and put it in the cup. Some groups had to measure 4 lots of 15ml. 
Secondly we measured the same amount of water and added it to the cup. We stirred the water and PVA together then we added the same amount of borax solution. We stirred and stirred with a spoon until the liquid was gone and we were left with a white gooey substance. 

The crazy putty smelled disgusting like chemicals and cleaning products. It smelled like mouldy things.
It looks like a white pancake, some of the putty was very shiny and glistening and other putty had small bubbles in it and one groups putty had cracks and small wrinkles in it.
The putty felt gooey, squishy, sticky, slimy, runny, frothy, damp, mushy and bouncy. It was warm to touch after it had been played with in our hands.

So why did the liquids come together to make a solid?

The PVA glue you use is a type of polymer called polyvinyl acetate (PVA for short), while the borax is made of a chemical called sodium borate. When you combine the two in a water solution, the borax reacts with the glue molecules, joining them together into one giant molecule. This new compound is able to absorb large amounts of water, producing a putty like substance which you can squish in your hands or even bounce ( sciencekids.co.nz)

2 comments:

  1. cool
    what if you put it in the sun
    sophie

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  2. Great question Soph! I really like how you are so keen to write comments on the blog. Keep up the great thinking!

    ReplyDelete