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VOCABULARY

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VOCABULARY

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  1. Safety Precautions:Wear safety goggles at all times!!! Or you will receive a detention and be removed from the lab.Sodium Tetraborate (Borax) is toxic by ingestion. Do not place in your mouth.Take care to keep the chemicals and slime away from your clothes.Dispose of all materials in the appropriate waste container

  2. VOCABULARY In a physical change, the starting substances (reactants) are not altered chemically. No new substances (products) are formed. Chemical bonds are not broken in a physical change. A physical change may affect the size, shape or color of a substance but does not affect its chemical composition. The substances may be changed from one phase to another phase (ice melts – solid to liquid), or separated (remove iron fillings from sand using a magnet) or combined (mixing sugar and water). In a chemical change, the starting substances (reactants) are altered chemically and the new substance (product) formed has different physical and chemical properties from the starting material. A chemical change is irreversible. A chemical change reaction is often observed by changes in a substance’s color, formation of gas (bubbles), change in odor, formation of heat, or formation of a precipitate (solid). Viscosity is the measure of the thickness of a liquid. Molasses and corn syrup are thick and have a high viscosity. Water and olive oil are thin and have low viscosity.

  3. Chemistry of Slime Reflections • Is the PVA slime a solid or a liquid? Explain how you know? • Is the cornstarch slime a solid or a liquid? Explain how you know? • Is the creation of PVA slime a chemical or physical change? How do you know? • Is the creation of cornstarch slime a chemical or physical change? How do you know?

  4. Silly Putty Lab Safety Precautions: Sodium Tetraborate (Borax) is toxic by ingestion. Do not place in your mouth.Take care to keep the chemicals and slime away from your clothes.Dispose of all materials in the appropriate waste container

  5. Non Newtonian Fluid • Non-Newtonian fluid is a fluid that has properties of both a solid and a liquid. The amount of force applied to a non-Newtonian fluid changes its viscosity. • Silly putty is a non-Newtonian fluid that is dilatant, that is, under stress, the material dilates or expands. Other stress-thickening materials are quicksand, wet sand on the beach, some printer’s inks, starch solutions, and Silly Putty. Dilatant materials tend to exhibit some unusual properties. • Under low stress, such as slowly pulling on the material, it will flow and stretch. If you are careful you can form a thin film • Pull sharply (high stress) and the material breaks • Pour the material from its container then tip the container upward slightly, the gel will self siphon • Put a small amount of the material on a table and hit it with your hand, there is no splashing or splattering • Throw a small piece onto a hard surface, it will bounce slightly • Stuff the material, through a tube, die swell occurs as it emerges

  6. Starting Materials • Polyvinyl Alcohol (PVA) is used as a thickener, stabilizer, and binder in cosmetics, paper cloth, films, cements, and mortars. Polyvinyl solution dries to leave a thin film that is finding use in packing materials. This film is left in the environment will break down rather than persist as some plastics do requiring clean up. • Sodium Tetraborate (Borax) is widely and diversely used, as a mild antiseptic, a cleansing agent, a water softener, a corrosion inhibitor for antifreeze, a flux for silver soldering, and in the manufacture of enamels, shellacs, heat-resistant glass (e.g., Pyrex), fertilizers, pharmaceuticals, and other chemicals. It is sometimes used as a preservative but is toxic if consumed in large doses.

  7. Data Table 2

  8. Further Testing of Silly Putty

  9. Chemistry of Slime Reflection • Questions: • Do the two starting materials (borax and liquid starch) exhibit the same chemical properties? Explain? • Do the two end products (silly putty) exhibit the same physical properties? Explain • Is silly putty a solid or a liquid? How do you know? • Is the creation of silly putty a chemical or physical change? How do you know?

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