Weird Science: March 29th, 2011 - Hawaii News Now - KGMB and KHNL

Weird Science: March 29th, 2011

HONOLULU- (HawaiiNewsNow)- Dr. V from Oceanit Hawaii shows Taizo Braden a new cool way to make a rubber ball out of common household items. Kids, get your parents permission before you make a mess. Check out the video!

 

Dr. V Show: Make your own Bouncy Ball

 

Things you need:

  • Borax (detergent enhancer)
  • Cornstarch
  • Cups to mix in
  • Elmer's glue (white or gel)
  • Food coloring
  • Warm water
  • Measuring spoons
  • Spoon or popsicle stick to stir
  • Plastic baggie
  • Marking pen

 

The experiment:

Label one cup "Borax" and the other cup "Ball." Put two tablespoons of warm water and half a teaspoon of borax powder into the cup labeled "Borax." Stir the mixture to dissolve the powder and add a little bit of food coloring. It's okay if some borax remains undissolved. This will give you a saturated solution. In the cup labeled "Ball," pour one tablespoon of glue and add half teaspoon of the borax solution and one tablespoon of cornstarch. DO NOT STIR. The ingredients need time to interact on their own so count to 15 first, and then stir them together to fully mix. What is the consistency of the mixture? The white glue will give you an opaque ball; glue gel will give you translucent ball. Once you can no longer mix your ingredients, take it out of the cup and start molding the ball in your hands, stretching and rolling it. The more you knead it, the more solid it will become. Once the ball no longer sticks to your hands, try and bounce it on a smooth surface, like the tabletop or floor. Please do not use on carpet or fabric and do not eat it. Keep your ball in a Ziploc bag in the refrigerator when you're not playing with it, or it will get really gross with fuzzy mold!

 

How does it work?

The glue molecules are long chains (polymers) that aren't connected to each other, so they slip and slide. That's why you can squeeze the glue out of the glue container.  The borax is the "connector" for the glue (polyvinyl acetate) molecules. Once the glue molecules start connecting together to you get a bouncy material. Think of a bowl of spaghetti to better understand why this polymer behaves in the way it does. When a pile of freshly cooked spaghetti comes out of the hot water and into the bowl, the strands flow like a liquid into the bowl. This is because the spaghetti strands are slippery and slide over one another. When all of the water evaporates, the spaghetti starts to stick to each other, eventually turning into a solid mass. Polymers are made out of long strands of molecules like spaghetti. If the long molecules slide past each other easily, then the substance acts like a liquid because the molecules flow, this is like your glue coming straight out of the bottle. If the molecules stick together at a few places along the strand, then the substance behaves like a rubbery solid called an elastomer. Borax is the compound responsible for hooking the glue's molecules together to form the bouncy ball.

 

Tips

Do not eat the ball, it's not toxic, but it's not good for you either!

Remember to wash your hands before and after playing with your slime.

Please throw your bouncy ball away in the trash, not down the sink.

 

 

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