SHRINKY DINKS : REUSING PLASTIC

SHRINKY DINKS : A WAY TO REUSE PLASTIC

Materials:

-         Coloured pens/permanent markers

-         Sandpaper

-         Scissors

-         Puncher

-         String

-         Oven

-         Petri dish

-         Oven

-         Oven gloves/ oven mitts ( to protect your hands when using the oven)

-         Clear plastic container

Procedure:

1.     Cut the clear plastic containers into the shapes desired. Then, sand one side of it lightly with sand paper. A bigger piece of plastic will shrink into a bigger piece when heated in an oven. When a piece of plastic is too small, it might sometimes shrink to such a small size that it will not produce the wanted effect.

2.     Punch a hole in the piece of plastic that is cut out. Remember; leave some space for pictures and words you might want to draw or write on it. This hole will also shrink to a small size when the plastic is heated.

3.     Draw on the piece of plastic that is cut out of the container with coloured pens or permanent markers. Leave the plastic for a few minutes to make sure the ink on it is dry. You can draw a picture, or even write words. But keep in mind when the plastic is heated; the picture and words will shrink along to a smaller size.

4.     Next, put the piece of plastic onto a petri dish and pop it into the oven to be heated for up to 3 minutes; give or take a little. Don’t get distracted; it takes a couple of minutes, but when the plastic shrinks; it happens quickly. If it is left for too long, the plastic will melt instead, so be careful. The new hardened and shrunken accessory-like product is called the ‘shrinky dink’.

5.     Take out the petri dish containing the shrink dink, and leave it outside to cool down. Once it has cooled down, you can pop a piece of string if you want to.

Why do plastic shrink?

Plastis are made of long chain-like molecules called polymers. Polymer chains are very long, so they can be manipulated to create a wide-range of properties, in this case for #6 plastic, polystyrene. Polystyrene is a thermosplastic, meaning the long polymer chains are heated and stretched, then cooled to form the plastic sheet when sanded using the sandpaper. The polystyrene remains in this stretched out state, unless something causes it to change. The cool thing about thermoplastics is that upon reheating plastic, it reverts to its original state. In other words; it shrinks. This is the same process used to ‘shrink wrap’ items like food containers or other products that have protective plastic wraps.

               Examples of shrinky dinks; but on opaque pieces of plastic.