November 29, 2011

Curious Mad Scientist George Help me with this science experiment...

So I have been trying to make slime with my class now for a while (it's a rotation so I get many attempts with many different children). We're using the tried-and-true PVA/Borax recipe (refer to Google) -- however when following the instructions it always ends up firm and rubbery, almost as firm as a bouncy rubber ball but not as will snap if you stretch it. For extra challenge: I have made it once but this experiment is always on the day I am on non-contact so my regular relief teacher is usually in charge. The one I use is this: 1/2c PVA and 1/2 cup water mixed together 1tbsp Borax in 1/4 water Add small amounts of the Borax solution until you get slime. But when my relief teacher does it (and the one time I did it), it goes almost directly to solid rubber ball-state. What am I doing wrong? (Oh, sorry, one more thing: could it be the actual PVA glue? I initially did it with classroom PVA and NOTHING happened -- turns out classroom PVA has a pathetic amount of PVA in it so it didn't react. Now I am using wood glue.)

  • This answer is as old-school as it is obvious: owl semen.
  • Holy God, don't even take the chance <:(!) male reproductive harm (shudder), lung problems like asthma (double shudder)... Real slime can be harvested from standing water outback.
  • Oh... And then you could view the natural progression of slime with a microscope or something. (The real horror is that this stuff comes out of the pipes in New Jersey every few months.)
  • I have never seen this PVA/borax slime but it sounds like what we used to call "Silly putty". This link suggests that "Adding acid to the slime breaks the crosslinking producing a liquid with lower viscosity". So maybe you should throw in a teaspoon of white vinegar or two. Although I am no chemist and that might have the same effect as mixing toilet cleaning chemicals. :-( Or perhaps your ratio of PVA to borax needs to be adjusted because your glue is a different percentage solution than your borax.
  • It looks like you've got too much borax. Most recipes I've seen have 4% borax solution and you've got about a 12% solution (if my math is right). Try 1 tsp borax to one cup of water. If the slime is too runny you can always try kneading it to remove moisture.
  • I made it yesterday and found that I needed to squeeze a lot of moisture out of it and still got the rubber ball effect. I'll try the more watery solution and see what happens... (Ha, and I only just noticed that I didn't actually say 1/4 CUP of water for the borax solution, so I'm gload you figured that out.)