This project will allow you to “see” the difference between AC and DC. You will need the following:
• Metal plate or pan
• Paper clip
• Piece of cloth
• Cornstarch
• Potassium iodide (available at a pharmacy)
• 9 volt battery
• 3 insulated wires with the insulation stripped off the ends
• Low voltage bell transformer (available at electronics or hardware stores)
Follow these steps:
1. Soak the piece of cloth well in a thick solution of cornstarch and water mixed with the
potassium iodide.
2. Lay the metal plate or pan with the bottom up. Wring the cloth out and lay it across the
metal plate or pan.
3. Use a wire to connect the negative terminal to one edge of the pan, using an alligator clip
or paper clip.
4. Connect the other wire to the positive end, and then slowly stroke the exposed end across
the cloth. (The electric current frees the iodine from the potassium iodide, making a dark
blue mark.) What pattern do you see? What kind of current are you using? Write your
answers.

Follow these directions and answer the questions. 1. set up the ripple tank as in previous investigations. 2. bend the rubber tube to form a "concave mirror" and place in the ripple tank. the water level must be below the top of the hose. 3. generate a few straight pulses with the dowel and observe the reflected waves. do the waves focus (come together) upon reflection? can you locate the place where the waves meet? 4. touch the water surface where the waves converged. what happens to the reflected wave? 5. move your finger twice that distance from the hose (2f = c of c, center of the curvature) and touch the water again. does the image (the reflected wave) appear in the same location (c of c)? you may have to experiment before you find the exact location. sometimes it is hard to visualize with the ripple tank because the waves move so quickly. likewise, it is impossible to "see" light waves because they have such small wavelengths and move at the speed of light. however, both are examples of transverse waves and behave in the same way when a parallel wave fronts hit a curved surface.

Disney, viacom and aol time warner are examples of

Clothes dryer uses about 7 amps of current from a 240 volt line. how much power does it use?