Objectives Investigate the properties of a common polymer. What To Do Set up four experiment stations and have students circulate through them. Give students sufficient time at each station to experiment and respond to the key questions. Gather students together to discuss the results.
Does it hold its shape? The essential physics is that silly putty is elastic on a short time scale and viscous on a long time scale. It will bounce when you drop it since the impact time is very short. But it will stretch when you pull it since the force is applied for a long time.
Long enough to untangle some of the long chain molecules in the polymer and long enough to break weak hydrogen bonds that link the long molecules. Like other polymers, the long molecules are not laid out in straight lines but become entangled during manufacture, like long strands of spaghetti.
Silly putty is described as being viscoelastic, as are thousands of other materials such as nylon, rubber, wood, food, human tissue, baseballs, tennis strings, earth, lava, etc. Almost any solid that is not a metal is viscoelastic to some extent. Understanding silly putty provides useful clues as to how all those other materials behave.
You can see what is happening more clearly when the heavy ball is dropped. Silly Putty is an amazing stretchy toy that's sold in a plastic egg.
In the modern era, you can find many different types of Silly Putty, including types that change colors and glow in the dark. The original product was actually the result of an accident. James Wright, an engineer at General Electric's New Haven laboratory, may have invented silly putty in when he accidentally dropped boric acid into silicone oil.
Earl Warrick, of the Dow Corning Corporation, also developed a bouncing silicone putty in Both GE and Dow Corning were trying to make an inexpensive synthetic rubber to support the war effort. The material resulting from the mixture of boric acid and silicone stretched and bounced farther than rubber, even at extreme temperatures. As an added bonus, the putty copied newspaper or comic-book print.
An unemployed copywriter named Peter Hodgson saw the putty at a toy store, where it was being marketed for adults as a novelty item. Hodgson bought the production rights from GE and renamed the polymer Silly Putty. He packaged it in plastic eggs because Easter was on the way and introduced it at the International Toy Fair in New York in February of Silly Putty was a lot of fun to play with, but practical applications for the product weren't found until after it became a popular toy.
Silly Putty is a viscoelastic liquid or non-Newtonian fluid. It acts primarily as a viscous liquid , though it can have properties of an elastic solid, too. There are covalent bonds within the polymer, but hydrogen bonds between the molecules. The hydrogen bonds can be readily broken. When small amounts of stress are slowly applied to the putty, only a few of the bonds are broken. Under these conditions, the putty flows.
When more stress is applied quickly, many bonds are broken, causing the putty to tear. Silly Putty is a patented invention, so specifics are a trade secret. One way to make the polymer is by reacting dimethyldichlorosilane in diethyl ether with water. The ether solution of the silicone oil is washed with an aqueous sodium bicarbonate solution. The ether is evaporated off. Powdered boric oxide is added to the oil and heated to make the putty.
These are chemicals the average person doesn't want to mess with, plus the initial reaction can be violent. There are safe and easy alternatives, though, that you can make with common household ingredients:.
This recipe forms a slime with a thicker consistency, similar to that of putty. Mix together 4 parts of the glue solution with one part of the borax solution. Add food coloring, if desired. Refrigerate the mixture in the sealed bag when not in use.
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