Fig. 125. Parallel circuits.
Fig. 126. How should he connect them?
Application 53. Dorothy was moving. "When they took out our telephone," she said to her chum, Helen, "the electrician just cut the wires right off."
"He must have turned off the electricity first," Helen answered, "or else it would all have run out of the cut ends of the wire and gone to waste."
"Why, it couldn't," Dorothy said. "Electricity won't flow off into the air."
"Of course it can if there is nothing to hold it in," Helen argued.
Which was right?
Inference Exercise
Explain the following:
321. It is very easy to get chilled when one is perspiring.
322. Ice cream becomes liquid if you leave it in your dish too long.
323. You should face forward when alighting from a street car.
324. There are always at least two electric wires going into a building that is wired.
325. Woolen sweaters keep you warm.
326. Steel rails are not riveted to railroad ties but the spikes are driven close to each rail so that the heads hook over the edge and hold the rail down without absolutely preventing its movement forward and backward. Why should rails be laid in this way?
327. The earth keeps whirling around the sun without falling into it, although the pull from the sun is very great.
328. Electricity is brought down from power houses in the mountains by means of cables.
329. White clothes are cooler than black when the person wearing them is out in the sun.
330. All the street cars along one line are stopped when a trolley wire breaks.
Section 36. Grounded circuits.
Why can a bird sit on a live wire without getting a shock, while a man would get a shock if he reached up and took hold of the same wire?