Wednesday, March 9, 2011

Cornstarch Polymer Lab Investigation

The hypothesis was proven, the polymer that was more stretchy and had a very rubber-y consistency. When we added the food coloring to the borax and water mixture, the color of the water became very dark and saturated, looking almost black when it was actually blue and red. The cornstarch was added to the mixture and lightened it considerably. The cornstarch did not change the constancy of the mixture, which surprised us. After the tests have been completed, the mixture separated. The very saturated color sat on top, while the borax and cornstarch sank to the bottom.

When the borax/cornstarch solution was added to the glue, it seemed to take longer to form then without the cornstarch. The color didn't transfer from the solution to the glue polymer very well, only a faint tint really remained. When we were molding the ball, it seemed that there were still some pockets of pure glue in the polymer. The polymer without cornstarch was more consistent in the mixture. When we took the polymer out, we discovered it was harder to mold with the cornstarch added. The polymer had a similar texture to the other experiment. It made noises when we were molding it, most likely because of the air pockets we observed it having. After molding it for a while, it began to become easier to mold as the actual temperature grew warmer.

Once we had the polymer formed into a ball, we performed a rebound and a stretch test. The rebound test was dropped from 30 cm, just like the previous polymer experiment. It bounced 22, 18, 19, and 16cm. This was similar to the chilled test of the pure glue and borax polymer. We took the ball-shaped polymer and performed a stretch test on it. It barely stretched at all before breaking, as did all of the polymers at all temperatures.  We later discovered that flattening the polymer would really reveal its stretch potential, but we were only able to test like that with the room temperature polymer. It stretched about 19 cm before breaking, which was considerably farther than the ball stretched at 7 cm.

The frozen rebound test produced about the same results as the room temperature test. It bounced 17, 17, 18, and 18 cm. The chilled polymer bounced extremely low, bouncing at 6, 8, 8, 2 cm. The chilled polymer may have bounced lower because of its shape, which was more oblong than round. By the time we bounced it, it had become pretty warm due to handling.

Overall, I think the polymer with cornstarch didn't have a huge difference from the polymer with just borax and white glue. The mixture used was exactly the same as the other mixture, with the addition of 1T of cornstarch. I don't think the food color changed anything, it just added a pop of color.

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