| Show WEAR mc APPARATUS instruct iv experiments made with it by prof J R at the lasic session of the utah county teachers association professor J B keeler gave a short lecture on 1 cheap scientific apparatus making twenty esteri ments with very simple utensils prepared for the occasion by way of introduction he remarked that he fully realized the position of the district school teacher how it is for hipfl to convince the school authorities that u few pieces of apparatus are absolutely necessary to satisfactory progress in borno porno kinds of class work must the teacher have implements for the illustration of subjects in the natural sciences which come up daily incidentally if otherwise not in regular work he must have thesa necessity is the mother of invention it is surprising extensive laboratory may be built up through the energy and ingenuity of the te achar aisted aa by the pupils by pursuing this course in timo abo i trustees will probably see abo in maintaining with funds this important part of the school equipment here is a dieca of magnetic iron ore obtained from iron county this kind of uro is found in various parts of the world and it has the property 0 attracting bits of iron as you see for it picks up these nails any body that has this property is called magnet pupils often get jcsse of nieces of magnetized iron and bring them to the teacher for an explanation of their wonderful action there are two kindy of magnets natural and artificial arti fical if this knitting needle bo rubbed on this dieco of iron ore you eee in ft short time it also possesses the power 0 o pick up email bits of iron this knitting needle now is called an artificial magnet kieel when unco magnetized gives up this condition very slowly there are other methods of producing artificial magnets by passing a current of electricity through a piece of insulated insolated inso wire wound many times around a piece of soft iron it will cause the iron to become magnetized wo can manufacture a small galvanic call to illustrate this process take a strip of copper and one of zinc about two inches square and place them in dilute sulphuric acid I 1 unite the two strips by a wire conductor and a current of electricity will bo produced you may pot tho copper and zinc of any good tinsmith strong vinegar will do instead of tho acid you aey this nail which is made of soft iron will not even attract a tack or pin but put it within the coil placing the copper and zinc in the acid bow it is a magnet powerful enough to attract small pieces of metal if a magnetized bar bo onried id filings of soft iron and then withdrawn you see tho filings will cling to it thickly about the two ends two points one near each end of the magnet are called its poles if this bar were allowed to sving freely by a cord one pole would point northward called the north seeking pole the other is called the south seeking polo observe when the north seeking end of one magnet is brought near tho south seeking pole of another they mutually attract as you see is the case with this needle mounted ou a pivot and the one held in my hand why does tho point toward north asks tho enquiring child indeed tho whole earth may bs considered a basit magnet having its magnetic poles near the geographical poles la our hemisphere the lines of magnetic force alf food toward th north magnetic pole ali magnets if left free to move will arrange themselves in nearly a north and south direction this is because of the magnetic property in the earth itself take this bit of artificial magnet that wo made a whilo ago by rubbing it upon tho magnetized iron ore place it apon a cork floating upon this saucer of water and we have a magnetic needle similar to those used in the marinero mariners ma compass is another force of na ture arid somo of its properties we will illustrato by a few simple experiments peri ments here is a small elder pith ball suspended by a silken thread fastened to a glass rod and all supported oy a common inkstand may reveal itself as charge residing on tho surface of this rebber ruler when the ruler is a pieer flannel or cats akin you will observe tho ball is first attracted and then repelled kub a piece of glass iu a similar manner and you see the pith ball is attracted observe then the electricity developed on glass is different in kind from that developed on the rubber ruler they exhibit opposite forces when brought near tho pith ball you see each attracting what the other repels ye may call therefore one kind of electricity positive and tho other negative As wo observed siva ilaray in I 1 he action of tho ma arnet so we see hare like kinde of electricity repel unlike attract under favorable with friction we might develop a spark by bringing the two kidds of electricity together it is supposed eup posed that lightning is the result of two clouds coming together charged with opposite kind of the teacher is obion asked to esplain the phenomenon of the rainbow wo ste that the rainbow is caused by beams of sunlight passing through the drops of rain thus dispersing the ray and sr reading tho colors on the dork cloade 03 a background back ground this process of nature may be explained by passing a ray of light through a piece of clear glass shaped like a prism you may obtain a piece good enough from an old chandelier with euca a prism allow a beam of light to pass into the room through a narrow slit in the window blind place in front of the alit the prism A beautiful band of colors will now be seen on the wall this band af colors is called the spectrum and the separation of the beada of light into its various color is called dispersion aca a by on examination it will be sen tb tace colors arrange in this order violet indigo blue green orange and redall of thes color esit esi t in a beam of light during a summer shuw fr when the conditions are the tiny raindrops act as prism alms forming a beautiful band of colors athwart the airy tho pupil often hears the teacher repeat the general law that haat expands most substances and cold on the other hand contracts them hwe now I 1 show you a sin all bott filled with colored water through its cork passes a glas tube open it both ends pass the bottle over the lamp immediately you see tho calorel liquid rise in the tube by the effect of expansion caused by heat again as tho vessel cools the descends in tho tube this simple experiment illustrates the general law upon this principle wr can explain the working of the thermometer take a small glass tube and fill it with quicksilver or batter still detach the tube from the thermometer that is on the wall here is plunging the tube into a glass of cold water melting ice is better the mercury sinks at a point which we mark A we now take the bulb and insert it in this goblet containing boiling water the mercury immediately rises and stops at a place which we mark B the distances between A and B indicate the differences 0 temperature that exist between the ice cold water and the boiling water we will mark the where the rested when it was in the glass of ice awatar 32 and the point indicated when immersed in the boiling aate this indicates the and the former the freezing in the scala on thermometer in tho centigrade thermometer tha freezing point is marked 0 and the boiling point is marked the distance between the freezing and the boiling points ia thus divided into one hundred parts in the centigrade scale or one hundred and eighty in the fahrenheit each of these parts is called a degree the speaker pave several other illustrations of tho expansion of liquids as the effect of heat one in particular by means of a hand glase on this blobs globs we live at the bottom of an atmospheric ocean as the fishes of the sea liva in the watery element the exerts a pressure of more than 14 pounds on every square inch crossing dalike in all directions air pumps are generally used to show its pressure but thoy are costly machines we may demonstrate the fact that the amo phere has weight by a few simple inexpensive asperi menta place the open end of a hollow key to the mouth and vigorously sucking out the air press it against the lipa and it will be held there tho of ha air here is another very faim alo example we fill this smooth edged tumbler arth water place a piece of strong writing paper over he top and pressing the palm at the hand against tho paper invert the tumbler see the baud may now bo removed from the paper and alu water will not run out as abe pressure of the air keeps it in and another ony we take this thin glass bottle and beat it over abo lamp net too hot thus causing the air within to expand aa heat will expand glasses as well as liquids and passing out for want of room invert the bottle over a saucer of colored water and yon as the air cools within thus occupying loss room abe water rises and partly fills abe bottle another experiment may be made here is a glass tube about 3 ft long it is solidly closed at one end rill this tube with water then with the finger stop up the open end and invert it into a glass filled with water withdrawing the finder abo tubo nevertheless remains full the water does not fall into the glass but remains supported three feet high in the tube if the tube were above the surface of the water in the vessel the result would be tho same if you can afford it mercury would bo much better for this experiment than water hero further explanations given by diagrams how often a teacher wishes be were possessed of an air purne what beautiful experiments ho might perform I 1 but did it ever occur to you that overy person carries with him a moat perfect machined mach ineT through this cork we pass a gaass tube open at both ends one orifice being seallor than ane other the larger end into a piece of rubber tubing then place the cork in this light colored beer bottle the air from the bow i hy maans of the lungs hut air pump pinch the end of abe rubber and im merge it in the colored water and lo 10 we have a beautiful in if v e had a air pump wo could not illustrate the pressure of abe atmosphere to a better advantage probably some twenty experiments experiment a have been performed before you all of these and all of the apparatus used as you see need cost more than a dollar and a hundred similar ones may be performed with no more cost MABIA |
