Part 16 (1/2)

2 dry cell batteries (905) A few feet of No 18 bell wire 3 steel knitting needles or siht cardboard or stiff paper Pere nails or spikes Red and black china-s Wire cutters Carpet tacks

(Iron filings usually can be found under the grinding wheel in a shop

If you can't find any, rub soether to produce bits of netic Field

Cover the pernet with the cardboard or paper Sprinkle iron filings on the paper Tap the paper and note the pattern fors pass fronet to the other The area covered by the filings is the center of the netic lines of force that arrange the iron filings to the contour strips in a farnetic field is one of the is in our everyday life with electricity If it were not for the netic field, ould not have electric s we use every day also depend on this ure 1]

Make an Electro-Magnet

You canseveral turns of insulated wire around one or e nails or spikes (soft iron)

Connect one end of the wire to the battery Touch the other end of the wire to the other terminal for a few seconds and see howas many turns as possible How many more tacks were you able to pick up?

[Illustration: Figure 2]

You have net When you disconnect the wire, the nails fall off This is one of the advantages of an electronetis the switch and picking up scrap iron and steel

Then he opens the switch to drop the scrap netized easily as you have just seen, but loses its netize but holds its net

Wrap the insulated bell wire around the steel knitting needle The wire should be wrapped the full length of the needle One end of the wire is connected to the battery The other end of the wire is then touched for just a few seconds to the other ternet If you did not get results, try two batteries in series, wind more turns of wire on the needle, and leave it connected a little longer Do the sa needle In the sanetize a screwdriver, so that you can use it to pick up and hold steel screws Don't do it unless you want your screwdriver to be ure 3]

See How They Attract and Repel

Take one of theit with a thread A thread stirrup (Figure 4) will help keep it level Be sure it is not near other large pieces of steel Watch the needle Does it settle down, pointing in one direction? (Check to see if this is the same direction as your compass) If it does, you havenorth is called the North Pole (North-seeking pole) The other end is called the South Pole Mark the North Pole with a stroke of the redwith the second needle You can show this with a sewing needle, and a notched cork, and a bowl of water Rest the needle in the notched cork, and float it on the water

[Illustration: Figure 4]

Hold the compass near the North Pole of the needle What happens? Does the South Pole of the needle attract the North or South Pole of the conetized needle See if you can prove the rule that like poles repel (drive away) and unlike poles attract

[Illustration: Figure 5]

Connect one end of a wire loop to the battery and run the wire directly over the compass Touch the other end of the wire to the battery Which way does the coet some netic field around the hen current is flowing This relation between electricity and enerators work