7.The Office of Science Education at the Jefferson Lab National Accelerator presents the phenomenon of water being deflected by a charged rod on their “Frostbite Theater” video clip (2:08). They also present a wrongexplanation of the deflection, saying the water molecules rotate so that their partial charge opposite that of the charged rod moves toward the rod and their partial charge the same as the rod moves away from the rod, causing the deflection: . Here is a correct, albeit short (1:13) explanation—induced charge: . 8.Here’s the polar-nonpolar charged rod deflection demonstration, done with a water stream and an oil stream. The teacher demonstrates while he explains the difference between polar and nonpolar substances. ()9.Here’s another take on the deflection of water demonstration. A magic wand that does miraculous things to a stream of water—an old physics trick involved creating a parabola shaped spray of water by taking a finely tipped glass tube connected to a rubber hose 45
10.“The “open” structure of Styrofoam™ can be dramatically demonstrated by placing a fewmilliliters of acetone in the bottom of a Petri dish and then setting an empty Styrofoam™ (expanded polystyrene—EPS) cup in the acetone. As the EPS “dissolves” in the acetone (for the real explanation of what occurs, see “More on other demonstrations that are not quite what they seem—Dissolving Styrofoam™”), the cup rapidly disappears. The open structure of the EPS (many cells) creates a large amount of surface area upon which the reaction takes place. Alternatively, a few centimeters of acetone can be placed in a large opaque container like a coffee can. Styrofoam™ packing “peanuts” can be added to the can.They will “disappear”. The number that can be added is rather amazing. Care should be exercised in handling the acetone. It is very flammable, and in addition, the demonstration should probably be done in a fume hood. The product should not be flushed
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