Background

Concept Video for Slime

  • K-3rd: One of the liquids we are using is called polyvinyl alcohol. Although it is a liquid here, polyvinyl alcohol is actually what’s called a plastic. Plastics are what Legos® and action figures are made out of. Like Legos®, plastics stack on top of each other and form a shape. At first, the polyvinyl alcohol we are using behaves like people passing by each other, they move freely. But when we mix polyvinyl alcohol and borax together, the polyvinyl alcohol and borax start to behave like people walking by each other, stopping, and holding hands. If enough people are holding hands, they form a long chain of people linked together. The polyvinyl alcohol is holding hands with borax and they start to form a long chain. These long chains of polyvinyl alcohol and borax stick together like Legos® and form the slime.
    • This activity meets the following NGSS:
      • 2-PS1-1 Different kinds of matter exist and many of them can be either solid or liquid, depending on temperature. Matter can be described and classified by its observable properties,
      • 2-PS1-2 & 2-PS1-3 Different properties are suited to different purposes,
      • 2-PS1-3 A great variety of objects can be built up from a small set of pieces,
      • 2-PS1-4 Heating or cooling a substance may cause changes that can be observed. Sometimes these changes are reversible, and sometimes they are not,
      • 2-PS1-3 Objects may break into smaller pieces and be put together into larger pieces, or change shapes.
  • 4th-6th: Plastics, like the toys you play with, are made out of molecules called polymers. These polymers are tightly packed together like Legos® stuck to one another. Polymers are made up of many smaller molecules called monomers and a monomer is made up of elements. You may have learned about elements from the periodic table. In this experiment, we will be using a polymer known as polyvinyl alcohol. When polymers are by themselves, they move freely past one another but when we mix them with borax like in this experiment, the borax links the polymers together just like a bridge links two pieces of land together. This linking together causes long strands of polymers to stick to one another which turns the polymers into to a gel.
    • This activity meets the following NGSS:
      • 5-PS1-2 The amount (weight) of matter is conserved when it changes form, even in transitions in which it seems to vanish,
      • 5-PS1-4 When two or more different substances are mixed, a new substance with different properties may be formed,
      • 5-PS1-2 No matter what reaction or change in properties occurs, the total weight of the substances does not change.
  • Middle school: Plastics are used to make a wide variety of things from toothpaste containers to mechanical pencils. Another name we have for a plastic is a polymer. Basically, these polymers are made up of a long chain of little molecules linked together called monomers. And these monomers are made up of mostly carbon, hydrogen, and oxygen elements found in the periodic table of elements. In this experiment, we will be mixing a polymer called polyvinyl alcohol with borax to form a new substance. When we mix these two materials together, a borax molecule links two polyvinyl alcohol molecules together like a bridge. Borax molecules keep linking polyvinyl alcohol molecules together which forms a repeating pattern that gives the liquid a structure, thus causing the liquid to form a gel. Also, the cross-linking between borax and polyvinyl alcohol traps water which is another reason why the liquid turn into a gel. If you allow the trapped water to dry out, the gel will become a solid.
    • This activity meets the following NGSS:
      • MS-PS1-1 Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms,
      • MS-PS1-2 & MS-PS1-3 Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it ,
      • MS-PS1-2, MS-PS1-2 & MS-PS1-2 Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants,
      • MS-PS1-5 The total number of each type of atom is conserved, and thus the mass does not change.
  • College-level/ Scientific description: By mixing polyvinyl alcohol with a borate anion, a chemical process known as polymerization takes place. During this process, a covalent bond forms in which the OH on the borate anion are replaced with oxygens from the hydroxyl groups on the polyvinyl alcohol backbone. Boron reacts with 1 -2 oxygens from each of two chains resulting in a cross-link. This cross-linking of the borate anion with the polyvinyl alcohol molecules forms a network of long chains of polyvinyl alcohols which traps in water, causing the liquid solution to become more viscous, creating a gel.