Friday, April 8, 2016

Silly Putty Chemistry

This year for Science Fair I've decided to do something with Silly Putty. Why Silly Putty? I recently got a tin of Crazy Aaron's Thinking Putty and two eggs of Silly Putty.  Enjoying these a lot, I wanted to learn more about this fun toy!

Silly Putty is a polymer. Polymers can be found in nature and also made synthetically. The chemical property of my homemade silly putty is the reaction between the two ingredients we used: Borax and glue.  We knew that the different glue/Borax ratios would mean differences in physical properties, such as stretchiness, bounciness...

My hypothesis: the more glue, the stretchier and stickier the putty would be; the more Borax, the more liquidy and less bouncy.

For our experiment we would first make our Borax and glue solutions, then make putties with different ratios and compare them.

1) Make two jars of solution: a 50% glue solution and a 4% Borax solution.

2) Mix varying ratios of glue to Borax solutions and put them in labelled ziplog bags.

3) Then squish it and wait for it to mix.

4) Play! We tested the physical properties by squashing, bouncing and stretching each sample.  One was so liquidy we couldn't take it out of its bag!

5) Write down observations for each putty.

The super stretchy one in the photo is a putty with a 2:2 ratio. Equal ratio?? Is my hypothesis wrong?

I found a common pattern in the putties that seemed to overturn my hypothesis. The ones with more glue were less stretchy and broke easily, but they were very bouncy.  My batch of 2:2 putty was very stretchy and gooey but not bouncy. Was more Borax better?
6) Adjust experiment. My first batch of putties has glue to Borax ratios of 1:3, 2:2, 3:1, 4:1, 5:1. I've decided to see whether or not more Borax would make the putty stretchier. So I made another batch with these ratios - 3:2, 4:2, 5:2.

When I felt the 4:1 in one hand and the 4:2 in the other, I noticed that the second batch (with higher level of Borax) was more durable and stretchier while the first batch was more flaky.

7) Conclusion: the experiment shows me that the more glue in the mixture, the more breakable but also more bouncy. The more Borax we have, the stretchier, stickier, and less likely for the putty to hold its shape.

After having so much fun with my 2:2 putty, I made a 4:4 which is now my favourite. Perfect slime!

1 comment:

  1. We can feel squeeze through our fingers Yuk.
    Love Nanny & Papa