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Background

Slime will introduce the two major types of chemical reactions, polymer chemistry and the importance of plastics in everyday life.

Real Life

Chemical reactions can be classified by whether they produce or absorb heat. Reactions that produce heat are called exothermic. They are quite common. Combustion or burning is an exothermic reaction.

The second type of reaction, called endothermic, absorbs heat from its surroundings. The reaction that produces slime is endothermic. It absorbs the heat from your hands as we handle it, which is why the slime feels cold and clammy to the touch.

The slime is a special kind of substance called a polymer. Polymers are more commonly known as plastics and are found practically everywhere in everyday life. For example, we use shopping bags, saran wrap and Tupperware, drive cars on rubber tires, and wear polyester, nylon and rayon fabrics. Polymers are substances made of repeating chemical units linked together like a chain to form a long molecule.

For example, the ethene molecule becomes the repeating
chemical unit when it is linked to other ethene molecule to form a polymer called polyethene.

Ethene  
 
Polyethene

 

What You Need

  • White glue (Elmer's school glue is best)

    •
  • Borax

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  • Water

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  • 2 medium-sized plastic containers

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  • Food colouring

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What To Do
  1. Mix 125 ml water with 125 ml glue in one container.

    2.
  1. Add the food colouring.

    2.
  1. In another container, mix 250 ml water with 45 ml borax.

    2.
  1. Add 60 ml of the borax solution to the glue solution and mix it with your fingers.

    2.
  1. Mush the mixture around with your hands until it thickens.  Then put it on a table and knead it with your hands until there is no obvious liquid on the surface of the slime.

    2.
  1. Stretch and squish the slime to observe how it behaves.  Is it a solid or a liquid?  Does it feel warm or cold?  It should feel cold, especially when it's stretched very thinly.  How thin can you stretch the slime before it breaks?  Does it stretch better when you pull on it quickly or when you pull on it slowly?

    2.
  1. Store slime in a resealable bag and keep it in a cool place.

    2.
  1. Remember the reaction needs heat, so the more the slime is handled, the harder it gets.

    2.

NOTE: The quantity of the two component solutions can be increased. Maintain the 1:1 ratio for the water and the glue mixture. For the Borax solution, add approximately three tablespoons of Borax per cup of water.