Experiment 2

The Relay in Action

Materials: 2 wood blocks 4” by 2” by ¾”. A wood block 2” by 2” by ¾”. Some nails, including 2 roofing nails l-1/2” long. 12’ of hookup wire. Metal strips. Popsicle stick. Thumb tack. 1-l/2-volt flashlight battery. 6-volt battery. 6-volt bulb. Bulb socket (the kind with wires already attached).

     RELAY FRAME. Using the drawing as a guide, nail the wood blocks together to form the frame. Then install a roofing nail about l-1/2” from the open end. The top of the nail should be slightly below the top of the upright wood block. Also, mark a spot l/4” from the open end for the other roofing nail, but don‘t pound that nail in yet.

      ELECTROMAGNET. Put about 100 turns of wire around the first roofing nail, leaving enough wire to make circuit connections. Keep the wire turns close together. When finished, twist the loose ends together so they won’t come apart. Now you can drive the second roofing nail in.

      CONTACT ARM. For this you’ll have to cut a 4” by 1” metal strip. Next, tape a piece of the popsicle stick to the end of the strip. Have the stick extend l/2” beyond the strip. Near the end of the stick, press in the thumb tack, with the head on the same side as the strip. Make sure the head is scraped clean. Then nail the strip to the frame so that the tack head is directly above the outermost roofing nail.