Why It Works
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Polymers are macromolecules (very big molecules) made of many smaller units called ‘mers’ that repeat throughout the chain. Polymers come in many sizes and shapes. They can be as hard and inflexible such as plumbing piping or as flexible as plastic wrap. All of these activities are polymers and are non-Newtonian liquids. Non-Newtonian means that if you jerk any of these substances, they break instead of stretch.
This simple polymer is made with starch and water. Starch is a natural polymer and water acts as a crosslinking agent. When starch and water mix, they hydrolyze or form temporary bonds. Cornstarch develops some very unique properties in the presence of water. The attraction is not permanent and once the cornstarch dries, it returns to the smooth powdery consistency that it had before hydrolysis occurred.
- Gluey Putty and Glue Ball
White glue consists of millions of chains of the polymer polyvinyl acetate which have been dissolved in water. These chains slip and slide freely but do not interfere with each other enough to pour much thicker than plain water. By adding borax (sodium tetraborate), the polyvinyl chains are linked together. This ‘cross- linking’ produces a product that is very different from glue. Sodium borate is the salt of a weak acid, boric acid H3BO3 or B(OH)3. Because the boric acid hydrolyzes in water, the ion that forms(B(OH)4) will crosslink the chains of a polymer. This crosslinking creates the different properties that are observed. The actual product depends on the amount of borax that is added. The more borax that is added, the more links are produced.
- Monster Flesh
This is also a polymer and will behave like the Gluey Putty until you add the vinegar. The blisters the monster gets when you pour vinegar onto it are due to the baking soda in the mixture. Baking soda and vinegar combine to give off carbon dioxide (the gas that made the bubbles).
Rocks and Crystals
- Crystal Garden
Crystals are formed when a supersaturated liquid solution solidifies. (Supersaturuation occurs when you fill a liquid with disolved material and no more will disolve.) Take a magnifying glass and look at the garden, you should be able to see the individual crystals within the larger structure.
Plants and Vegitables
- Colorful Celery
Every kid has tried this at least once, but have you ever stopped to wonder why this works? Just like a straw, the "strings" in the celery are hollow. Also like a straw, they carry water from the ground (or cup) to the tips of the stems. But this is not all. The same way a tall tree has vascular pressure due to the giving off of oxygen, the celery does too. As the leaves at the top of the celery stalk carry out photosynthesis, the water in the "strings" is used up, there is a vacuum formed at the top, forcing the colorful water through the celery stalk.