,experimental ,glass ,blowing ,,for ,,boys ,,by ,,carleton ,j4 ,,lynde1 ,,ph4 ,d4 ,professor of ,physics ,mac,donald ,college1 ,quebec ,province1 ,canada ,prepared under the direction of ,,alfred ,c4 ,,gilbert ,,yale ,,university1 #aiji ,,experimental ,,glass ,,blowing ,boys1 glass tubes are made in the sizes shown in ,fig4 #b1 and in larger sizes4 ,you will use sizes #b1 #d1 and #f in the following experiments4 ,experiment #a4 ,fun bending glass4 ,illustration3 ,,fig4 #b ,,sizes ,,of ,,glass ,,tubing ,hold a piece of ,no4 #b1 with both hands1 in the flame of the alcohol lamp1 and turn it constantly 7,fig4 #c74 ,do you find that when the glass becomes nearly red hot1 it becomes soft and bends easily8 ,illustration3 ,,fig4 #c ,,heating ,,glass ,,to ,,soften ,,it ,take the tube out of the flame1 bend it into any shape you wish 7,fig4 #d71 and allow it to cool4 ,do you find that the glass hardens when it cools and retains the bent shape8 ,heat the tube near the first bend1 turn it constantly1 take it out of the flame1 and make another bend4 ,repeat this and make all kinds of fantastic shapes4 ,place all hot glass on the cooling blocks1 not on the table4 ,glass is used in many1 many ways by the human race2 for example1 to make bottles1 tumblers1 window glass1 and so on1 and all of these uses depend upon the facts which you have just illustrated1 namely1 that glass becomes soft when heated and hard when cooled again4 ,illustration3 ,,fig4 #d ,,bending ,,glass ,,the ,,lamp ,the wick should be cut straight across and should project above the wick holder about inch 7,fig4 #e71 or a little more if you require more heat4 ,burn wood alcohol or grain alcohol1 because they give flames without soot or smoke4 ,fill the lamp to within a inch of the top only2 it will burn one hour4 ,the hottest part of the flame is not down close to the wick1 as most beginners suppose1 but up just beneath the tip4 ,illustration3 ,,fig4 #e ,,the ,,lamp ,buy your alcohol at a drug store in quantities of one pint or more4 ,when you are through experimenting for the day pour the alcohol from the lamp back into the pint bottle and cork the bottle tightly4 ,alcohol left in the lamp gradually evaporates and is lost4 ,do not let the lamp stand with alcohol in it for any considerable time--overnight for example--because fuel alcohol contains water and when it evaporates from the wick1 the alcohol evaporates first and leaves the water in the wick4 ,then when you try to light the wick again1 you will find that you cannot do so1 because1 of course1 water does not burn4 ,if this happens to you1 take the wick out1 dry it1 and start the lamp again4 ,illustration3 ,,fig4 #f ,,making ,a ,,scratch ,it is perfectly safe to use kerosene in the lamp1 but it gives a very smoky flame which deposits soot on the glass and fills the air with soot particles4 ,your mother will object very strenuously to this because the soot particles settle and blacken everything4 ,burn alcohol only1 at least in the house4 ,experiment #b4 ,to cut glass tubing4 ,illustration3 ,,fig4 #g ,,breaking ,,the ,,tube ,cut off a six-inch length of ,no4 #b as follows3 ,lay the tube flat on the table1 mark the six-inch length and draw the file across the tube at this point1 pressing hard enough to make a good scratch 7,fig4 #f74 ,grasp the tube with both hands near the scratch1 as in ,fig4 #g1 pull apart and bend slightly4 ,do you find that the tube breaks across easily8 ,repeat this with ,no4 #d and ,no4 #f tubes4 ,experiment #c4 ,to make the edges smooth4 ,illustration3 ,,fig4 #h ,,making ,,the ,,edges ,,smooth ,hold one end of the six-inch piece of ,no4 #b in the tip of the flame 7,fig4 #h71 and turn constantly until it is just red hot4 ,take it out and let it cool on the blocks4 ,do you find that the edges are smooth8 ,repeat with the other end4 ,repeat with both ends of the six-inch piece of ,no4 #d4 ,if thick glass is heated quickly it may crack1 because the hot exterior expands more quickly than the cooler interior and produces internal strains4 ,illustration3 ,,fig4 #i ,,the ,,blowpipe ,,flame ,the ,no4 #f tube is comparatively thick and should be heated gradually as follows3 ,hold the end in the flame for about #a second1 then withdraw it for about #a second2 hold it in the flame again for #a second1 and withdraw it for #a second4 ,repeat this eight or ten times1 then hold and turn it in the flame until red hot4 ,smooth both ends of the ,no4 #f piece in this way4 ,experiment #d4 ,practice with the blowpipe4 ,hold the small end of the blowpipe just inside the flame at one edge1 about inch above the wick 7,fig4 #i71 and blow air through the flame parallel to the top of the wick4 ,keep your mouth closed on the blowpipe1 breathe through your nose1 and practice keeping a steady stream of air going for a long time4 ,you will be able to do this with a little practice4 ,do you observe that the blowpipe flame is pointed1 also that it is made up of a pointed cone inside and a lighter-colored cone outside8 ,the hottest part of the flame is inside the outer cone just beyond the point of the inner cone4 ,illustration3 ,,fig4 #aj ,,closing ,,one ,,end ,,of ,a ,,tube ,the blowpipe flame is hotter than the lamp flame because the heat of the burning alcohol is concentrated at one point by means of the air blast1 and because the alcohol is more completely burned by the extra air4 ,experiment #e4 ,to close the end of a small tube4 ,hold one end of a piece of ,no4 #b tube in the blowpipe flame 7,fig4 #aj71 turn it slowly1 and heat until the end closes4 ,does it close nicely8 ,close one end of a piece of ,no4 #d in the same way4 ,you can close ,no4 #f tubing in this way1 but it leaves a large lump of glass which may crack on cooling or on reheating4 ,you will practice closing ,no4 #f tubing later4 ,the 8why0 of it ,the glass becomes soft when heated because it becomes almost a liquid1 and if it is heated sufficiently it becomes entirely a liquid4 ,in this respect it acts very much as pitch1 rosin1 and wax act when heated by the sun or by a fire4 ,illustration3 ,,fig4 #aa ,,making ,a ,,glass ,,bubble ,the end of a glass tube becomes smooth1 or closes entirely1 when heated1 for the following reason3 ,the surface of any liquid tries to take the smallest possible area 7this is explained in detail under 8,surface ,tension0 in the ,gilbert book on 8,experimental ,mechanics071 for example1 a small particle of water takes the shape of a drop1 a sphere1 and the surface of a sphere has the least area for a given amount of water4 ,now when the end of the glass tube is heated it becomes a liquid1 and the surface of this liquid contracts the glass into a smooth rounded surface of least area4 ,if the tube is heated still more1 the surface contracts still more and closes the end4 ,experiment #f4 ,fun blowing glass bubbles4 ,smooth one end of a piece of ,no4 #b tube and allow it to cool4 ,close the other end in the blowpipe flame1 turn it slowly1 and heat until it is very hot4 ,take the tube out of the flame1 put the smooth end into your mouth quickly1 and blow as hard as you can 7,fig4 #aa74 ,do you get a fine big glass bubble which bursts with a pop8 ,if you get only a small bulb at the first trial1 heat the end1 and try again4 ,do you find that the bulb shrinks when heated but blows out again readily8 ,illustration3 ,,fig4 #ab ,,blowing ,a ,,bulb ,when you get a big bubble1 place the bubble end of the tube on a cooling block and break all the thin glass away from the tube by striking it with the file or blowpipe4 ,then close the end and blow another bubble4 ,repeat until you can blow bubbles easily4 ,repeat with a piece of ,no4 #d tube4 ,,bubble ,,colors ,illustration3 ,,fig4 #ac ,a ,,water ,,balloon ,do you find that the thin glass of the bubbles shows colors1 especially in sunlight1 just as soap bubbles do8 ,you boys who have had the ,gilbert set on 8,light ,experiments0 will know that these colors are due to 8interference40 ,the colors produced by a thin film of oil on water are also produced by 8interference40 ,experiment #g4 ,to make water balloons4 ,close one end of the ,no4 #b tube in the blowpipe flame again and while it is still hot blow carefully into the open end until you have a bulb about inch in diameter 7,fig4 #ab74 ,now let it cool4 ,make a scratch with the file about inch from the bulb1 break the tube at this point 7,fig4 #ac71 and smooth the rough edge4 ,illustration3 ,,fig4 #ad ,,the ,,balloon ,,sinks ,,and ,,rises ,put the bulb in a tumbler of water4 ,does it float8 ,if not1 make another balloon with a larger bulb4 ,experiment #h4 ,magic4 ,find a large bottle made of clear glass1 the neck of which will fit your solid rubber stopper4 ,fill the bottle with water to overflowing1 insert the balloon1 and then the stopper4 ,now press down hard on the stopper4 ,does the balloon sink in a most magical manner 7,fig4 #ad78 ,release the stopper4 ,does the balloon rise in an equally magical manner8 ,illustration3 ,,fig4 #ae ,a ,,balloon ,,race ,experiment #i4 ,balloon races4 ,make another water balloon4 ,put the two balloons together in the bottle filled to overflowing with water4 ,insert the stopper and press down hard4 ,do the balloons sink 7,fig4 #ae71 and does one sink more quickly than the other8 ,release the stopper4 ,do the balloons rise1 and does one rise more quickly than the other8 ,the most buoyant balloon sinks last and rises first4 ,the 8why0 of it ,illustration3 ,,fig4 #af ,,drawing ,a ,,thin ,,tube ,you boys who have the ,gilbert set on 8,hydraulic and ,pneumatic ,engineering0 will know the 8why0 of the last three experiments4 ,any body floats in water if it is lighter than an equal volume of water1 and it sinks if it is heavier than an equal volume of water4 ,water is practically incompressible but air is very compressible3 thus when you press down on the stopper1 you force water into the balloon and compress the air in it2 when you release the stopper1 the compressed air in the balloon expands and drives the water out4 ,when the weight of the balloon and the weight of the water in it are together greater than the weight of water displaced by the balloon1 the balloon sinks2 when they are less1 it rises4 ,experiment #aj4 ,fun with thin tubes4 ,hold a piece of ,no4 #b tubing in the lamp flame and turn it constantly4 ,when it is red hot and soft1 take it out of the flame and pull your hands apart until the tube is stretched ten or twelve inches 7,fig4 #af74 ,is the tube in the shape shown in ,fig4 #ag8 ,illustration3 ,,fig4 #ag ,a ,,glass ,,tube ,,stretched ,allow the tube to cool1 break the large ends away from the thin tube1 place one end of the thin tube in a glass of water1 and blow into the other end to make air bubbles in the water 7,fig4 #ah74 ,if you can do so1 it is a real tube4 ,illustration3 ,,fig4 #ah ,,air ,,through ,,tube ,does the thin tube bend easily and does it spring back when released8 ,repeat the experiment with another piece of ,no4 #b tubing1 but make the thin tube as long as you can4 ,can you blow air through the thin tube1 and does it bend very easily indeed8 ,repeat with a piece of ,no4 #d tubing4 ,these thin hairlike tubes are called 8capillary0 tubes1 from the ,latin word capillus1 meaning a hair4 ,experiment #aa4 ,magic4 ,illustration3 ,,fig4 #ai ,,water ,,runs ,,uphill ,you have always heard that water runs downhill1 but you will now see it run uphill and remain there in a most magical manner4 ,cut off #e-;inch lengths of ,no4 #f1 ,no4 #d1 and ,no4 #b tubing1 stand them side by side in a glass full of water 7,fig4 #ai71 and move them up and down in the water to wet the inside of the tubes4 ,now look at the water level in each of the tubes4 ,is it above the level of the water in the glass1 and is it higher the smaller the inside diameter of the tube1 that is1 is it higher in the ,no4 #b than in ,no4 #d1 and in ,no4 #d than in ,no4 #f8 ,now take the thin capillary tube which has the largest inside diameter1 place one end in the glass of water1 suck it full of water and blow it out4 ,now with one end in the glass of water notice quickly how the water rises inside the tube4 ,does it run uphill in a most magical manner 7,fig4 #bj71 and does it remain there8 ,illustration3 ,,fig4 #bj ,,water ,,runs ,,up ,,tube ,repeat this with your other capillary tubes4 ,does the water run uphill in each1 and does it rise higher the smaller the inside diameter of the tube8 ,the 8why0 of this is explained in ,gilbert's 8,experimental ,mechanics0 under 8,capillarity40 ,,what ,,is ,,glass8 ,common glass is made from three substances with which you are all more or less familiar2 namely1 sand1 sodium carbonate 7washing soda71 and lime4 ,if sand and soda or potash are mixed and heated to a high temperature1 they melt together and produce a glass which dissolves in water4 ,this is known as 8water glass0 and it is used in many ways3 to preserve eggs1 to cement fire bricks1 to make fireproof cement1 and so on4 ,if1 however1 lime is added and the mixture is heated to a high temperature1 a glass is produced which is not soluble in water4 ,this is the glass you know4 ,the three most common kinds of glass are3 ,venetian glass1 made from sand1 soda1 and lime2 ,bohemian glass1 from sand1 potash1 and lime2 and crystal or flint glass1 from sand1 potash1 and lead oxide4 ,illustration3 ,,fig4 #ba ,,second ,,step ,,in ,,making ,,window ,,panes ,illustration3 ,,fig4 #bb ,,ironing ,,the ,,cylinders ,,flat ,,how ,,are ,,things ,,made ,,of ,,glass8 ,the glass mixture is heated to a high temperature in fire clay pots or tanks in large ovens4 ,the surface is skimmed from time to time and the heating is continued until all air bubbles have escaped from the mixture1 usually about three days4 ,the glass is now quite fluid and it is allowed to cool somewhat until it is viscous2 then the objects are made by blowing1 pressing1 or rolling1 as described below4 ,the finished articles are finally 8annealed10 that is1 they are placed while still hot in a second hot oven1 which is then sealed and allowed to cool slowly1 for four or five days or for as many weeks1 according to the kind of glass4 ,if a glass object cools quickly1 it cools more rapidly on the surface than in the interior4 ,this produces a condition of strain in the glass and the object may drop to pieces when jarred or scratched4 ,this condition of strain is avoided by allowing the objects to cool very slowly1 that is1 by annealing4 ,,window ,,glass ,window glass is blown in exactly the same way as you have blown glass balloons2 the process is illustrated in ,fig4 #a4 ,the glass mixture is heated for about three days in fire clay pots and is allowed to cool until it is viscous4 ,the glass blower then attaches a lump of the viscous glass to the end of a straight iron blowpipe about five feet long and blows a bulb4 ,he then reheats the glass and blows a larger pear-shaped bulb and in doing so rests the glass on a pear-shaped mold of charred wood 7see center of ,fig4 #a74 ,he again reheats the glass1 holds the pear-shaped bulb over a pit1 and blows a long cylinder 7see left of ,fig4 #a74 ,the ends of the cylinder are now cut off and the edges are smeared with molten glass to prevent splitting 7see right1 ,fig4 #ba74 ,the cylinder is next cut lengthwise with a diamond 7center1 ,fig4 #ba71 and is placed in a second hot oven1 where it is ironed out flat 7,fig4 #bb74 ,illustration3 ,,fig4 #bc ,,bottles ,,blown ,,in ,a ,,mold ,the flat sheets are finally annealed in a third oven for a number of days and are then cut into panes1 sorted1 and packed4 ,,glass ,,tubes ,illustration3 ,,fig4 #bd ,,rolling ,,plate ,,glass ,the glass tubes with which you do the experiments in this book are made in the same way as window glass up to the stage of blowing the cylinder2 then the blower's helper attaches an iron rod to the opposite end of the cylinder 7see right of ,fig4 #a71 and the blower and helper walk backward away from each other to pull the cylinder into a tube4 ,of course1 they use a small amount of glass to make small tubes1 and larger amounts for large tubes4 ,,molded ,,glass ,many articles of glass are made by blowing the glass in molds4 ,bottles are made in this way 7,fig4 #bc71 and large machines are now in use which mold many bottles at one time in this way4 ,,pressed ,,glass ,many articles are made by pressing glass into molds1 that is1 the molten glass is poured into molds and is pressed against the sides of the mold by means of a plunger4 ,imitation cut glass is pressed in this way4 ,,plate ,,glass ,the large sheets of plate glass used in store windows are not blown1 but rolled4 ,the molten glass is poured from the fire clay pots upon a cast-iron table and is rolled flat by means of a large iron roller 7,fig4 #bd74 ,the glass is then in the shape of plate glass1 but is rough on both sides4 ,it is annealed for a number of days and then is ground smooth on both sides1 first with coarse emery1 then with finer and finer emery1 and is finally polished with rouge4 ,the result is the beautifully polished plate glass we see in large windows4 ,,optical ,,glass ,the ,united ,states and ,great ,britain made great strides in the manufacture of optical glass during the war and there are now many kinds on the market4 ,they are used in making the lenses1 prisms1 and mirrors for optical instruments4 ,optical glass is made in much the same way as ordinary glass1 but great care is taken3 first1 to see that the materials are pure2 second1 to stir the glass constantly1 as it cools from the molten to the viscous state1 to make it as uniform as possible2 and third1 to cool it very slowly in the annealing process1 to avoid strains4 ,,quartz ,,glass ,illustration3 ,,fig4 #be ,a ,,pollywog ,an entirely new glass has been placed on the market in quantity in recent years4 ,it is made by melting very pure quartz sand at a temperature of #cjjj ,f4 and cooling it fairly rapidly4 ,it has the very valuable property of expanding and contracting very1 very slightly when heated and cooled4 ,thus there is practically no internal strain set up when it is heated or cooled quickly and it does not break4 ,it can be heated red hot1 for example1 and then plunged into cold water without breaking4 ,it is probable that this glass will be in universal use in a very few years4 ,experiment #ab4 ,to make an acrobatic pollywog4 ,smooth one end of a piece of ,no4 #b tube to put in your mouth1 close the other end in the blowpipe flame1 take it out and blow a bulb about inch in diameter4 ,allow the bulb to cool1 then heat the tube about inch from the bulb and draw it out into a thin tube4 ,now bend the thin tube at right angles near the bulb and break it off 7,fig4 #be74 ,place the bulb in water4 ,does it float8 ,if not1 blow another with a larger bulb4 ,experiment #ac4 ,magic4 ,illustration3 ,,fig4 #bf ,,acrobats ,place the pollywog in a bottle filled to overflowing with water1 insert the solid rubber stopper1 and press it down hard4 ,does the pollywog sink8 ,now release the stopper quickly4 ,does the pollywog turn somersaults in a most magical manner 7#a1 ,fig4 #bf71 and also rise8 ,make one or two more pollywogs1 place them all in the bottle together 7#b1 ,fig4 #bf71 and entertain your friends with a pollywog circus4 ,the pollywog sinks when you press down on the stopper because you compress the air in it and force water in until it weighs more than the water it displaces4 ,illustration3 ,,fig4 #bg ,,dancing ,,pollywogs ,the pollywog rises when you release the stopper because the compressed air drives the water out until the pollywog weighs less than the water it displaces4 ,the pollywog turns a somersault because the water rushes out sidewise in one direction and forces the nozzle in the other direction4 ,air may escape from the pollywog when it is turning a somersault2 if so1 water will take its place1 and may make the pollywog too heavy to float4 ,you can restore its buoyancy by sucking out the water4 ,experiment #ad4 ,a dancing pollywog4 ,illustration3 ,,fig4 #bh ,,drawing ,,glass ,,spider-,,webs ,make a pollywog as in ,experiment #ab1 but bend its tail twice as shown in #a1 ,fig4 #bg2 the nozzle is at one side and points sidewise4 ,illustration3 ,,fig4 #bi ,,the ,,spider ,,trick ,put it in the bottle full of water1 then press down and release the stopper4 ,does it sink and rise1 and does it also whirl around most beautifully as it rises8 ,make another pollywog 7#b1 ,fig4 #bg71 but bend its nozzle in the opposite direction4 ,does it whirl in a direction opposite to that of the first pollywog8 ,put them in the bottle together and treat your friends to a pollywog dance4 ,the pollywog whirls because the water rushes out of the nozzle in one direction and forces the nozzle in the opposite direction4 ,experiment #ae4 ,to make glass spider-web4 ,heat the end of a piece of ,no4 #b tube in the blowpipe flame until it is melted and very hot4 ,now touch the end of another piece of glass to the melted glass1 remove from the flame1 and quickly pull the two pieces apart as far as you can 7,fig4 #bh74 ,do you find that you have pulled part of the melted glass out into a very fine glass spider-web8 ,repeat1 but ask a friend to touch the second piece of glass to the first and run away as fast as he can4 ,do you get a much finer spider-web8 ,is the glass spider-web fairly strong and very flexible8 ,experiment #af4 ,the ancient spider trick4 ,illustration3 ,,fig4 #cj ,,attaching ,a ,,handle ,attach an imitation spider--or the dead body of a real spider--to the end of the glass spider-web and surprise your friends1 as shown in ,fig4 #bi4 ,the glass spider-web is much less visible than a thread for this purpose4 ,experiment #ag4 ,to make working handles4 ,you can save glass in many cases by attaching a short piece of glass to the piece you intend to work with1 as follows3 ,heat an end of each piece in the lamp flame until red hot1 press them together1 remove from the flame1 and hold until solid4 ,the short piece then serves as a working handle 7,fig4 #cj7 for the large piece4 ,experiment #ah4 ,to close a large tube4 ,you closed small tubes in ,experiment #e by simply heating the end in the blowpipe flame4 ,this method does not serve for large tubes1 however1 because it leaves a very large lump of glass which may crack on cooling or reheating4 ,illustration3 ,,fig4 #ca ,,closing ,a ,,large ,,tube ,illustration3 ,,fig4 #cb ,,making ,a ,,submarine ,practice the following method of closing a large tube2 first with a piece of ,no4 #d tube1 and then with a piece of ,no4 #f3 ,attach a working handle to the end to be closed1 heat the tube inch from the end in the blowpipe flame1 turn constantly1 and when soft pull apart until the tube has the shape #a1 ,fig4 #ca4 ,heat1 turn1 and pull the end away to leave the tube as in #b4 ,heat the end and blow out until it has the shape #c4 ,the end is now closed and the glass has about the same thickness as the remainder of the tube4 ,experiment #ai4 ,to make a submarine4 ,close one end of a piece of ,no4 #b tubing as described above1 but leave the end somewhat pointed 7#a1 ,fig4 #cb74 ,heat the tube on one side at a distance inch from the end and blow a bulb about inch in diameter 7#b74 ,heat the tube inch from the bulb1 draw it down into a fine tube1 and break off the tube1 leaving a small hole in the end 7#c74 ,place the submarine in a glass of water1 and if it floats it is complete4 ,experiment #bj4 ,magic4 ,illustration3 ,,fig4 #cc ,,the ,,submarine ,,submerges ,fill a bottle to overflowing with water1 insert the submarine open end down1 insert the solid rubber stopper and press down hard 7,fig4 #cc74 ,does the submarine submerge8 ,release the stopper4 ,does the submarine rise and does it also move forward8 ,turn the bottle on its side and release the stopper quickly4 ,does the submarine shoot forward at a great rate 7,fig4 #cd78 ,the submarine acts in this magical manner for the reasons given in ,experiment #i4 ,when you press the stopper in1 you compress the air in the submarine and force water in until the submarine weighs more than an equal volume of water and it sinks4 ,when you release the pressure on the stopper1 the compressed air forces the water out until the submarine becomes lighter than an equal volume of water and it rises4 ,the water rushing out through the opening exerts pressure backward on the water in the bottle and the reaction drives the submarine forward4 ,experiment #ba4 ,fun with the submarine4 ,if your friends do not know about the little submarine1 you can mystify them as follows3 ,tell them that submarines are just like other fish2 namely1 they lay eggs1 and the little eggs hatch out after a certain number of days 7of course1 your friends will know that you are only joking74 ,pretend that you found one of these submarine eggs1 hatched it out in lukewarm water1 and that you have trained the baby submarine to do some simple tricks4 ,for example1 that you have trained it to submerge1 rise1 and attack1 when you issue the commands 8submerge10 8rise10 and 8attack40 ,illustration3 ,,fig4 #cd ,,the ,,submarine ,,shoots ,,forward ,tell them to watch the submarine carefully and to notice that it takes in water and submerges when you issue the command 8submerge40 ,stand the bottle on the table1 issue the command 8submerge0 and1 while your friends are watching the submarine1 press down on the stopper unknown to them4 ,illustration3 ,,fig4 #ce ,a ,,submarine ,,battle ,tell them to watch the submarine carefully again and to notice that it expels water and rises when you issue the command 8rise40 ,issue the command and unknown to them release the pressure on the stopper slowly4 ,repeat with the command 8attack0 and release the pressure quickly4 ,experiment #bb4 ,a submarine battle4 ,make a second submarine1 place it in a large bottle with the first submarine1 turn the bottle on its side1 and make the submarines manuver by moving the stopper in and out4 ,illustration3 ,,fig4 #cf ,,flaring ,a ,,tube ,finally arrange them so that they are on the bottom1 facing each other bow to bow1 two or three inches apart 7#a1 ,fig4 #ce71 and release the stopper quickly4 ,do the submarines try to ram each other 7#b1 ,fig4 #ce7 in a most realistic manner8 ,illustration3 ,,fig4 #cg ,,an ,,air ,,gun ,experiment #bc4 ,to flare the end of a tube4 ,heat the end of a piece of ,no4 #b tube until it is red hot1 take it out of the flame1 hold the flaring wire inside the end1 and press outward gently while you revolve the tube 7#a1 ,fig4 #cf74 ,do you find that the end is flared out 7#b1 ,fig4 #cf78 ,experiment #bd4 ,to make an air gun4 ,take a full length piece of ,no4 #d tube and flare both ends slightly4 ,this is the air gun 7,fig4 #cg74 ,now to make an arrow1 cut off the lighting end of a match and insert a pin in the other end 7,fig4 #ch74 ,illustration3 ,,fig4 #ch ,,the ,,arrow ,,is ,,shot ,,pin-,,end ,,first ,insert this arrow in the air gun and blow it out4 ,does it come out with considerable speed8 ,experiment #be4 ,a shooting match4 ,illustration3 ,,fig4 #ci ,a ,,shooting ,,match ,draw a target on a piece of paper and hang it up1 away from the wall or at the edge of the table1 where there will be space behind for the arrows to pass through4 ,now shoot at the target with your air gun 7,fig4 #ci74 ,do you find that the arrow makes holes in the target and sometimes goes right through8 ,the bull's-eye of a target is usually #a inch in diameter1 the next circle outside is #b inches in diameter1 the next #d inches1 and the outer circle #e inches4 ,get up a shooting match and keep track of the score made by each4 ,if the bull's-eye is cut anywhere by the arrow1 the count is #e points2 a cut anywhere inside or touching the #b-;inch circle counts #d points2 anywhere inside or touching the next two circles counts #c and #b points respectively4 ,the one who makes the highest score in five shots is the winner4 ,it is more sanitary if each shooter has his own air gun and arrows4 ,experiment #bf4 ,height and distance contest4 ,go outside and see which of you can shoot his arrow to the greatest height and to the greatest distance4 ,give each contestant five shots4 ,illustration3 ,,fig4 #dj ,,the ,,pea ,,shooter ,,in ,,action ,you can make fair estimates of the heights if you shoot up beside a building or tall tree4 ,experiment #bg4 ,to make a pea shooter4 ,illustration3 ,,fig4 #da ,,bends ,take a full length piece of ,no4 #f tubing1 smooth both ends and flare them out slightly4 ,this makes an excellent pea shooter4 ,try it with peas4 ,do you find that they come out with great speed8 ,experiment #bh4 ,a pea-shooting match4 ,make a target on a piece of paper1 hang it up away from the wall or at the edge of the table1 and shoot at it 7,fig4 #dj74 ,do you find that the peas go right through the paper8 ,arrange a match with your friends and keep track of the score as in ,experiment #be4 ,experiment #bi4 ,to make a good bend4 ,a good bend has the same diameter in the bend as in the remainder of the tube 7#a1 ,fig4 #da74 ,it is rather difficult to make because the tube tends to cave in on the inside of the bend 7#b7 or flatten on the outside 7#c71 or both4 ,illustration3 ,,fig4 #db ,a ,,drinking ,,tube ,make the bend as follows3 ,heat a piece of ,no4 #b tube about #b inches from one end in the lamp flame1 turn it constantly and move it back and forth endwise to heat a length of about #b inches4 ,when soft1 take the tube out of the flame1 and bend the ends upward until the angle is #ij4 ,if the bend is flat on the inside or outside1 close one end of the tube in the blowpipe flame1 smooth the other end and allow them to cool1 then heat the flat side of the bend in the blowpipe flame and blow it out slightly4 ,this makes the diameter of the tube at the bend equal to that of the remainder of the tube4 ,cut off the closed end1 smooth the edge1 and your bend is complete4 ,make bends with ,no4 #d tube4 ,illustration3 ,,fig4 #dc ,a ,,siphon ,experiment #cj4 ,to make a drinking tube4 ,many times when there is sickness in the house1 it is convenient to have a glass drinking tube 7,fig4 #db71 through which the patient can drink without raising his head4 ,make such a tube from a piece of ,no4 #d tubing4 ,the short arm is equal in length to the depth of the tumbler2 the long arm1 or mouthpiece1 is about #a inch longer than this4 ,experiment #ca4 ,to make a siphon4 ,cut off a piece of ,no #d tubing #h inches long1 make two right-angled bends about #a inch apart at the center1 smooth both ends1 and your siphon is complete 7,fig4 #dc74 ,illustration3 ,,fig4 #dd ,a ,,siphon ,experiment #cb4 ,magic4 ,put one arm of the siphon in a tumbler of water and suck air out of the other end4 ,does the water start running and does it continue to run in a most magical way 7,fig4 #dd7 until the water is below the end of the siphon in the tumbler8 ,illustration3 ,,fig4 #de ,,from ,,the ,,high ,,level ,,to ,,the ,,low ,fill the tumbler with water again1 start the water running1 put the outer arm of the siphon in an empty tumbler1 and stand both tumblers on the table 7,fig4 #de74 ,does the water run up one arm of the siphon and down the other into the empty tumbler8 ,does it stop running when the levels are the same8 ,stand the first tumbler on a book4 ,does the water run again and stop when the levels are again the same 7,fig4 #df78 ,place the lower tumbler on the book and the upper tumbler on the table4 ,does the water now run in the opposite direction until the levels are again the same8 ,raise one tumbler a foot or so above the table4 ,does the water run up over the edge and drop into the second8 ,now before the upper tumbler is empty1 lower it in such a way that an arm of the siphon is in each tumbler1 and raise the second tumbler4 ,does the water now run in the opposite direction8 ,illustration3 ,,fig4 #df ,,the ,,water ,,stops ,,when ,,levels ,,are ,,the ,,same ,you boys who have the ,gilbert set on 8,hydraulic and ,pneumatic ,engineering0 will know that it is the pressure of the atmosphere which causes the water to run up over the edge of the tumbler in this magical way4 ,experiment #cc4 ,a long-armed siphon4 ,illustration3 ,,fig4 #dg ,,siphoning ,,with ,,long ,,tubes ,attach a full length of ,no4 #d tube to each arm of the siphon1 as in ,fig4 #dg1 and repeat the experiments described above4 ,note3 ,when you insert a glass tube into a rubber coupling or rubber stopper1 wet the end of the glass tube and the inside of the coupling or stopper1 grasp the tube near the end to be inserted1 and insert with a twisting motion4 ,experiment #cd4 ,to make a nozzle4 ,attach a working handle to one end of a piece of ,no4 #b tube1 heat the tube about one inch from the end in the lamp flame1 turn constantly until soft1 then remove from the flame1 and draw it out about #c inches4 ,when cool1 break off the thin tube1 cut off the nozzle to a length of about #b inches1 smooth the large end1 and your nozzle 7,fig4 #dh7 is complete4 ,experiment #ce4 ,to make a fountain4 ,arrange the apparatus as in ,fig4 #di1 and suck air out of the nozzle4 ,have you made a beautiful fountain8 ,illustration3 ,,fig4 #dh ,a ,,nozzle ,illustration3 ,,fig4 #di ,,fig4 #ej ,,fig4 #ea ,,fig4 #eb ,,you ,,make ,a ,,number ,,of ,,magic ,,fountains ,experiment #cf4 ,magic4 ,make a nozzle #f inches long out of ,no4 #b tube4 ,smooth the ends of the nozzle1 and long tubes4 ,arrange the apparatus as in ,fig4 #ej and suck air out of the nozzle until the water runs in the siphon4 ,does the water squirt out of the nozzle in a magical manner8 ,experiment #cg4 ,more magic4 ,arrange the ,no4 #b apparatus as in ,fig4 #ea1 with the nozzle inside the bottle4 ,now to start the apparatus3 ,fill the bottle about quarter full of water1 insert the tubes in the stopper as shown2 insert the stopper into the mouth of the bottle2 invert the bottle2 then put the short tube in a tumbler full of water and the long tube in an empty pail or basin4 ,is there a magical fountain inside the bottle8 ,repeat this with a taller bottle1 if you can find one to fit your two-hole stopper4 ,do you get a higher fountain8 ,experiment #ch4 ,still more magic4 ,illustration3 ,,fig4 #ec ,,starting ,a ,,siphon ,make another nozzle and attach it to the apparatus used in the last experiment by means of the inverted siphon 7,fig4 #eb74 ,start the experiment as described above4 ,do you get two fountains8 ,experiment #ci4 ,to start a siphon4 ,illustration3 ,,fig4 #ed ,,siphoning ,,sand ,you can start a siphon without sucking the air out of it as follows3 ,fill the siphon with water1 put a finger over each end 7#a1 ,fig4 #ec71 place one end in a tumbler full of water and remove the finger under water 7#b1 ,fig4 #ec71 then remove the other finger4 ,does the siphon start8 ,in this case the water you pour into the siphon drives the air out1 and this is the reason you do not need to suck the air out4 ,experiment #dj4 ,to siphon sand or mud4 ,arrange a siphon 7,fig4 #ed71 start the water flowing1 and then pour sand or mud into the upper tumbler4 ,is the sand of mud siphoned over into the lower tumbler8 ,illustration3 ,,fig4 #ee ,a ,,squirt ,,bottle ,attach a long tube to the outer arm of the siphon and repeat the experiment4 ,is the sand or mud siphoned more rapidly and more thoroughly8 ,experiment #da4 ,to make a squirt bottle4 ,illustration3 ,,fig4 #ef ,,squirt ,,bottle ,,in ,,action ,make a nozzle at one end of a piece of ,no4 #b tubing1 make a bend near the nozzle1 cut off the other end at such a length that it will reach to within inch of the bottom of the bottle1 smooth this end1 allow it to cool1 wet the tube and the two-hole stopper1 shove it through one hole of the stopper1 insert an elbow in the other hole1 and your squirt bottle is complete 7,fig4 #ee74 ,fill the bottle with water1 and blow through the elbow4 ,do you get a fine long stream from the nozzle 7,fig4 #ef78 ,illustration3 ,,fig4 #eg ,,tube ,,for ,,trick ,,squirt ,,bottle ,experiment #db4 ,to make a trick squirt bottle4 ,you can have any amount of fun with a trick squirt bottle4 ,it is exactly the same as the squirt bottle described in ,experiment #da except that it has a hole just below the bend 7,fig4 #eg74 ,illustration3 ,,fig4 #eh ,,making ,a ,,small ,,hole ,to make the hole1 make the long bent nozzle as in the last experiment1 then heat the tube just below the bend in the blowpipe flame1 touch a piece of glass tube to the red-hot glass 7#a1 ,fig4 #eh71 and pull it away 7#b1 ,fig4 #eh74 ,do you find that the hot glass is pulled out into a thin pointed tube8 ,break off the thin tube close to the large tube1 heat in the blowpipe flame until the edges are smooth and at the same level as the sides of the large tube4 ,flare the edges of the hole1 if necessary2 it should be about inch in diameter4 ,illustration3 ,,fig4 #ei ,,trick ,,squirt ,,bottle ,now fill the bottle with water1 and blow hard 7,fig4 #ei74 ,do you find that one stream of water is driven into your face and another out of the nozzle8 ,experiment #dc4 ,fun with a trick squirt bottle4 ,illustration3 ,,fig4 #fj ,,trick ,,bottle ,,in ,,action ,now to have fun with your trick bottle1 show it to one friend at a time4 ,do not ask him to try the bottle1 just go where he can see you and squirt a long stream1 but unknown to him have your finger over the hole below the bend4 ,illustration3 ,,fig4 #fa ,a ,,simple ,,engineer',s ,,level 7,from ,aldous' ,physics4 ,courtesy of ,the ,macmillan ,company7 ,your friend will just naturally want to have a try at it4 ,so you say 8,all right1 let's see who can squirt the longest stream40 ,tell him that all he has to do is to take a deep breath and blow as hard as he can4 ,he will do so1 with laughable results 7,fig4 #fj74 ,now together find another friend4 ,do not ask him to blow1 but each of you blow as long a stream as you can1 where he can see you4 ,he will beg to be allowed to try1 and finally you let him1 with the same laughable results4 ,illustration3 ,,fig4 #fb ,,one-,,legged ,,table ,,and ,,level ,repeat with other friends4 ,experiment #dd4 ,to make an engineer's level4 ,you can make one form of engineer's level 7,fig4 #fa7 as follows3 ,take a full length of ,no4 #f tubing1 bend it up #d inches at each end1 smooth the ends1 attach it to a small board1 rest the board on a one-legged table1 and you have a serviceable level 7,fig4 #fb74 ,fill the tube with water1 shove the pointed end of the leg into the ground and sight along the outside of the upright tubes at the level of the water surfaces4 ,the line along which you sight is exactly horizontal1 because the water surfaces are at exactly the same level4 ,experiment #de4 ,to use the engineer's level4 ,illustration3 ,,fig4 #fc ,,homemade ,,level ,,in ,,use ,an engineer's level is used to find the difference in level of two or more points 7,fig4 #fc74 ,to practice using your level1 find the difference in level of two points #ajj feet apart on a road1 sidewalk1 or railroad4 ,to do this1 you must first make what is called a leveling rod4 ,find a piece of wood about one or two inches square and six or more feet long1 mark on it feet and inches1 beginning at the bottom end1 and your leveling rod is complete4 ,now to find the difference in level of two points #ajj feet apart1 scratch a line or insert a small stake at one point1 then pace off #ajj feet and mark the second point4 ,now set up your level between the two points1 ask a friend to hold the rod on the ground and upright1 at the first point1 sight along the water levels at the rod1 and ask your friend to move his finger1 or a white card1 up and down until it is exactly in your line of sight4 ,now ask your friend to tell you exactly where his finger or card is and record this height4 ,let us suppose that it is #d feet #f inches above the ground4 ,now leave the level exactly where it is1 ask your friend to hold the rod upright at the second point1 and again sight along the water levels at the rod4 ,let us suppose that his finger or card is now exactly #c feet above the ground4 ,the difference in level at the two points is #d feet #f inches minus #c feet or #a foot #f inches4 ,that is1 the second point is #a feet above the first point or the grade is #a4e feet in #ajj1 or #a4e per cent4 ,you can now mark a third point #ajj feet beyond the second point1 set up your level between the second point and third point1 place the rod at the second point1 then at the third point1 and find their difference in level as above4 ,if the third point is #a foot above the second1 the total rise in the #bjj feet is #b feet2 if1 however1 it is #a foot below the second1 the rise is #a minus #a or foot in the #bjj feet4 ,you can repeat this with as many points as you please4 ,illustration3 ,,fig4 #fd ,a ,,spirit ,,level ,experiment #df4 ,to make a spirit level4 ,the spirit level 7,fig4 #fd7 is simply a curved glass tube filled with alcohol except for the bubble and closed at both ends4 ,the curve of the tube is part of a circle4 ,illustration3 ,,fig4 #fe ,,making ,a ,,spirit ,,level ,make a spirit level as follows3 ,take a piece of ,no4 #d tube about #g inches long1 heat a space about #c inches long in the lamp flame1 turn constantly1 and when soft remove from the flame1 hold both ends and allow the center to sink into a slight curve 7#a1 ,fig4 #fe74 ,let the tube cool1 mark the center of the curve with ink1 and make marks #b inches from the center on each side4 ,hold the tube crosswise in the lamp flame1 heat at one mark1 draw down the tube and close it 7#b74 ,in a similar manner draw down the tube at the other mark but do not close it 7#c74 ,let the tube cool and fill it with alcohol to the level shown in #d4 ,to do this easily make the pipette 7#e71 suck alcohol into it within about #a inch of the top1 put your finger over the top1 insert the lower end of the pipette to the bottom of #d1 and remove your finger4 ,illustration3 ,,fig4 #ff ,,mounting ,,the ,,spirit ,,level ,heat the small part of #d1 without heating the alcohol1 and close the tube 7#f74 ,now attach the level to a smooth board as #b or #c1 ,fig4 #ff1 mark the center of the bubble1 and your spirit level is ready for use4 ,experiment #dg4 ,to make a fountain-pen filler4 ,attach a rubber coupling to the large end of one of your ,no4 #d nozzles1 close the other end of the coupling with a glass plug1 and your fountain-pen filler is made 7,fig4 #fg74 ,to make the plug1 close one end of a piece of ,no4 #d tubing1 allow it to cool1 cut off to a length of #a inch and smooth the rough edges4 ,insert the closed end of this plug into the rubber coupling4 ,practice using the filler by drawing up and shooting out water4 ,illustration3 ,,fig4 #fg ,a ,,fountain-,,pen ,,filler ,experiment #dh4 ,to make a syringe4 ,take a half length of ,no4 #f tube and smooth both ends in the lamp flame or blowpipe flame4 ,now to make a plunger3 ,cut an #h-;inch length of ,no4 #b4 smooth one end1 close the other end and blow a slight bulb4 ,when cold1 wet the closed end and insert it into a small wet rubber coupling4 ,note3 ,always grasp a tube near the end when you insert it into a coupling or stopper1 because if you hold it too far back you may break it4 ,insert it with a twisting motion1 after wetting the end and the inside of the coupling or stopper4 ,illustration3 ,,fig4 #fh ,a ,,syringe ,wet the inside of the large tube1 wet the plunger and rub it on a cake of soap to make it slippery1 then try it in the large tube4 ,if the plunger is too large1 stretch the coupling lengthwise2 if it is too small1 crowd the coupling together lengthwise4 ,if the bulb is too large or too small1 dry it1 heat in the blowpipe flame until it shrinks1 and blow another4 ,when the plunger is made1 attach a ,no4 #d nozzle to the ,no4 #f tube with a large coupling1 arrange as in ,fig4 #fh1 and your syringe is made4 ,fill the large tube with water and see how long a stream you can make4 ,illustration3 ,,fig4 #fi ,,another ,,syringe ,experiment #di4 ,to make another syringe4 ,heat a piece of ,no4 #f in the blowpipe flame at a length of #g inches and draw it out into a nozzle2 smooth the other end in the lamp flame4 ,use the same plunger as in ,experiment #dh1 and your syringe is made 7,fig4 #fi74 ,try it out with water4 ,experiment #ej4 ,to make a third syringe4 ,heat a piece of ,no4 #f tube in the blowpipe flame at a length of #g inches1 draw it out1 and close the end1 then smooth the other end4 ,now to make a plunger3 ,heat a piece of ,no4 #b tube #h inches from one end in the lamp flame1 draw it out into a nozzle1 and break it off1 leaving a small hole at the end of the nozzle4 ,smooth the other end in the lamp flame1 flare it out slightly1 allow it to cool1 dip it into water and insert it into a small wet coupling4 ,illustration3 ,,fig4 #gj ,a ,,third ,,syringe ,now fill the large tube with water and insert the coupling plunger 7,fig4 #gj74 ,do you get a fine long stream8 ,experiment #ea4 ,to make a diablo whistle4 ,use the ,no4 #f tube and the ,no4 #b plunger from ,experiment #dh1 arrange as in ,fig4 #ga1 blow across the top1 and move the plunger up and down4 ,do you get a most diabolical sound8 ,illustration3 ,,fig4 #ga ,,the ,,diablo ,,whistle ,the sound is produced by the vibration of the air column between the top of the tube and the top of the plunger4 ,do you find that the pitch of the note is higher the shorter the air column8 ,experiment #eb4 ,fun with the diablo whistle4 ,start with the air column long and blow the note1 shorten it a little and blow the next note1 continue1 and try to blow the eight notes of an octave4 ,illustration3 ,,fig4 #gb ,,joining ,,two ,,tubes ,try to play a tune4 ,try to make the most weird sound you can4 ,experiment #ec4 ,to join two tubes end to end4 ,take a piece of ,no4 #b tube about #g inches long1 close one end1 smooth the other1 and when cool cut the tube at the middle4 ,illustration3 ,,fig4 #gc ,,working ,,the ,,joint ,now join these two pieces as follows3 ,hold the ends opposite each other near the top of the lamp flame 7,fig4 #gb71 rotate constantly1 and when nearly red hot bring the ends accurately together in the flame1 press together slightly1 draw out slightly1 and remove from the flame4 ,the ends are now stuck together1 but the glass is in a slight lump around the joint and if allowed to cool will crack very easily4 ,it is necessary to work the glass back and forth to get rid of the lump and to make the glass uniform on both sides of the joint4 ,do this as follows3 ,heat one third of the joint in the blowpipe flame 7,fig4 #gc71 and when red hot blow a slight bulge4 ,now turn the joint one third1 heat the next third red hot and blow a slight bulge4 ,repeat with the remaining third4 ,illustration3 ,,fig4 #gd ,,joining ,,tubes ,,of ,,different ,,sizes ,now heat the first third again until it is red hot and shrinks1 then blow a slight bulge again4 ,repeat this with the other two thirds4 ,repeat this whole operation a third time and blow just enough to leave the joint the same size as the remainder of the tube or a little larger4 ,illustration3 ,,fig4 #ge ,,making ,a ,,large ,,hole ,this heating and blowing has worked the joint back and forth until the glass is fairly uniform4 ,it makes a strong joint4 ,cut off the closed end and smooth the edge4 ,repeat with a piece of ,no4 #d tube4 ,illustration3 ,,fig4 #gf ,,making ,a ,,tee ,experiment #ed4 ,to join tubes of different sizes4 ,take a piece of ,no4 #d tubing about #c inches long and close one end4 ,illustration3 ,,fig4 #gg ,,three-,,armed ,,siphon ,take a piece of ,no4 #f tubing1 attach a handle to one end1 heat the ,no4 #f tube in the blowpipe flame about #a inch from this end and draw it down to smaller size4 ,break the small part at a point where it is about the size of the ,no4 #d tube4 ,if the hole is too large1 heat the edge until it is a little too small and flare it out with the flaring tool4 ,if the hole is too small1 heat the edge and flare it out4 ,now heat the ends of both tubes 7,fig4 #gd71 and join them as described in the last experiment4 ,repeat the operation of heating and blowing at least three times4 ,join a ,no4 #d and a ,no4 #b tube in the same way4 ,experiment #ee4 ,to make a large hole4 ,take a piece of ,no4 #d tube about #f inches long1 close one end1 smooth the other1 and allow it to cool4 ,illustration3 ,,fig4 #gh ,a ,,repeating ,,air ,,gun ,now to make a large hole in the side of this tube1 proceed as follows3 ,heat in the blowpipe flame the point at which you wish to make the hole1 and blow a slight bulge 7#a1 ,fig4 #ge74 ,then heat the top of this bulge until it is red hot over an area about equal to the size of the hole you wish to make1 and blow hard to make a thin bubble 7#b1 ,fig4 #ge74 ,break away the thin glass of the bubble1 smooth the edges1 and the hole is made4 ,the edge of this hole will project beyond the side of the tube 7#c1 ,fig4 #ge74 ,if you wish to make the edge even with the side of the tube1 heat it in the blowpipe flame until it shrinks back level with the tube4 ,illustration3 ,,fig4 #gi ,,four-,,way ,,junction ,experiment #ef4 ,to make a tee4 ,take a piece of ,no4 #d tube about #f inches long1 close one end1 smooth the other1 and allow it to cool4 ,take another piece #c inches long1 close one end1 and allow it to cool4 ,now make a hole in the side of the first tube at a point #c inches from the closed end4 ,do this as described in the last experiment but leave the hole projecting beyond the side of the tube 7#a1 ,fig4 #gf74 ,illustration3 ,,fig4 #hj ,,making ,a ,y ,now heat the edge of the hole and the end of the short piece in the lamp flame1 and make a joint 7#b1 ,fig4 #gf7 exactly as described in ,experiment #ec4 ,be particular to heat and blow all around the joint at least three times to make the glass uniform1 and on the last blowing leave the joint a little larger than the tube4 ,cut off the closed ends1 make the arms equal in length1 smooth the ends1 and your tee is made 7#c1 ,fig4 #gf74 ,your first attempt may not be beautiful1 but if you will repeat the heating and gentle blowing often enough1 the joint will be strong1 which is the main point4 ,repeat until you can make a tee easily4 ,make a tee with ,no4 #b tubing4 ,your flame is hardly large enough to make a tee with ,no4 #f tubing4 ,experiment #eg4 ,a three-armed siphon4 ,make a three-armed siphon as shown in ,fig4 #gg4 ,put two arms in tumblers filled with water1 suck air out of the third arm until the water runs1 and then put it in an empty tumbler4 ,stand the three tumblers on the table4 ,does the water run until the levels are the same8 ,put one tumbler on a book4 ,does the water run into the other two tumblers until the levels are the same8 ,return the one tumbler to the table and put the other two on the book4 ,does the water run from both tumblers to the lower tumbler until the levels are again the same8 ,experiment #eh4 ,to make a repeating air gun4 ,illustration3 ,,fig4 #ha ,,balancing ,,columns ,take a full length of ,no4 #d tubing1 put a branch about #c inches long at a point about #b inches from one end2 leave the end of the branch closed 7,fig4 #gh74 ,now load the branch with shot or coarse dry sand1 and your repeating air gun is ready for use4 ,tilt the branch slightly above the horizontal and blow intermittently4 ,does your gun reload after each blow1 until the ammunition is used up8 ,experiment #ei4 ,to make a four-way junction4 ,make a tee as in ,experiment #ef1 but do not cut off the closed ends4 ,now attach a fourth arm1 as in ,fig4 #gi1 and heat and blow gently as before to work the glass into uniform condition4 ,cut off the closed arms at equal lengths1 smooth the ends1 and your four-way junction is made4 ,experiment #fj4 ,a four-arm siphon4 ,make a four-arm siphon1 repeat the experiments described in ,experiment #eg1 and make others of your own4 ,experiment #fa4 ,to make a ,y4 ,make a tee as in ,experiment #ef1 then make a bend about inch from the stem on each side 7,fig4 #hj71 and your ,y is complete4 ,experiment #fb4 ,balancing columns4 ,arrange the apparatus as in ,fig4 #ha1 put the arms together in a glass of water1 suck a little air out of the top coupling and close it with a glass plug4 ,do you find that the water rises to the same level in each8 ,place the arms in separate tumblers filled with water to the same level and repeat4 ,does the water rise to the same level8 ,illustration3 ,,fig4 #hb ,,the ,,water ,,levels ,,are ,,the ,,same ,add an extra length to one arm and repeat4 ,are the levels different but are they equal distances above the water in their respective tumblers8 ,place the tumblers on the table1 make one tube slanting1 and repeat the experiment 7,fig4 #hb74 ,are the levels again the same8 ,when you suck air out of the tee1 you decrease the air pressure in the two tubes1 and the atmospheric pressure on the water in the tumblers lifts the water into the tubes4 ,experiment #fc4 ,unequal columns4 ,put a large handful of salt into a tumbler partly filled with water and stir until the salt is dissolved4 ,now pour fresh water into another tumbler until it is at the same height as the salt water4 ,make the arms of equal length1 put one arm in the salt water and the other in the fresh water1 then suck a little air out of the top coupling and close it with a plug4 ,do you find that the column of salt water is shorter than the column of fresh water 7#a1 ,fig4 #hc78 ,it is shorter because salt water is heavier than fresh water4 ,illustration3 ,,fig4 #hc ,,unequal ,,columns ,if you have gasoline or kerosene convenient fill one tumbler half full of either1 and the other tumbler half full of water1 then repeat the experiment4 ,do you find that the column of gasoline or kerosene is longer than the column of water 7#b1 ,fig4 #hc78 ,it is longer because gasoline and kerosene are lighter than water4 ,experiment #fd4 ,to fuse wire into glass4 ,find a piece of thin iron or copper wire about #d inches long1 heat the end of a piece of ,no4 #b tubing until it is nearly closed1 insert the iron or copper wire into the small hole1 and heat the glass around the wire until it shrinks and grips the wire firmly 7,fig4 #hd74 ,the glass then serves as a handle for the wire4 ,illustration3 ,,fig4 #hd ,,wire ,,fused ,,into ,,glass ,it is difficult to make a secure joint between iron or copper wire and glass because they both expand and contract more than glass when heated and cooled4 ,it is easy to make a secure joint between platinum wire and glass because platinum and glass expand and contract at practically the same rate when heated and cooled4 ,platinum1 however1 is too expensive to be used for ordinary experiments4 ,experiment #fe4 ,to cut window glass4 ,the common glass cutter is a small very hard steel wheel mounted on a handle 7,fig4 #he74 ,practice with one on a pane of glass3 place a ruler on the glass1 draw the wheel along the ruler 7,fig4 #hf7 with sufficient pressure to scratch the glass1 place the under side of the scratch exactly over the edge of the table1 and press down on both sides4 ,illustration3 ,,fig4 #he ,a ,,glass ,,cutter ,experiment #ff4 ,to bore a hole in glass4 ,illustration3 ,,fig4 #hf ,,cutting ,a ,,pane ,,of ,,glass ,place a piece of window glass flat on the table1 pour a little kerosene on the spot to be bored1 clasp the file near the end1 press the end down hard on the spot and turn it back and forth with a gouging motion 7,fig4 #hg74 ,you twist the file just as you would twist an awl to force it into hard wood4 ,you will soon penetrate the surface2 use plenty of kerosene and continue the boring until you are nearly through2 then turn the plate over and start a hole on the other side to meet the one you have made4 ,illustration3 ,,fig4 #hg ,,boring ,a ,,hole ,,in ,,glass ,do not rush things2 it will take you ten or fifteen minutes to bore through ordinary window glass4 ,bore a hole in a bottle in the same way1 except that the boring is all from the outside4 ,if the end of the file becomes dull1 break off a small piece1 with a pair of pliers1 to expose a fresh surface4 ,experiment #fg4 ,to cut a bottle in two4 ,illustration3 ,,fig4 #hh ,,bottle ,,ready ,,to ,,be ,,cut ,,in ,,two ,wind a strip of blotting-paper or wrapping paper #b inches wide around the bottle at one side of the line along which you wish to cut4 ,make three or more thicknesses and then tie the paper with cord within inch of the edge to be cut4 ,wrap another similar piece on the opposite side of the place to be cut and inch from the first piece 7,fig4 #hh74 ,illustration3 ,,fig4 #hi ,,heating ,,the ,,bottle ,now stand the bottle in a pail of water until the paper is thoroughly wet 7about five minutes71 take it out1 rotate it in a horizontal position and direct the blowpipe flame against the glass between the papers 7,fig4 #hi74 ,continue this for four or five minutes1 then if the bottle has not dropped apart1 plunge it vertically into the pail of water4 ,the bottle will break into two parts along the line between the two papers 7,fig4 #ij74 ,if it does not do so1 repeat the operation until it does4 ,smooth the rough edges outside and inside with the file4 ,you cannot do this with the flame because the glass is too brittle4 ,illustration3 ,,fig4 #ij ,,the ,,bottle ,,cut ,,in ,,two ,experiment #fh4 ,to grind glass4 ,rough edges of glass can be ground smooth by means of emery paper4 ,for example1 to smooth the edges of the glass bottle you have just cut in two1 use the file for the rough work1 then lay a piece of emery paper on a plate of glass1 emery side up1 pour a little kerosene on it and rub the rough surface on the emery with a rotary motion 7,fig4 #ia74 ,finish with fine emery paper1 and smooth the edges inside and out with the fine paper4 ,illustration3 ,,fig4 #ia ,,smoothing ,,the ,,edges ,experiment #fi4 ,to cement glass4 ,there are two important points to remember in cementing glass3 first1 to get the glass clean1 and second1 to press the surfaces together after applying the cement1 to squeeze out as much of the cement as possible1 and to keep them pressed together until the cement is hard4 ,to clean the glass wash it thoroughly with soap and water1 rinse1 and dry with a clean cloth4 ,illustration3 ,,fig4 #ib ,,cementing ,,glass ,there are many excellent glass cements on the market4 ,some of these are solid and are used only on hot glass2 others are liquid and are used on cold or hot glass4 ,cement two strips of glass together 7,fig4 #ib7 with sealing wax or solid shellac or some other solid cement as follows3 ,clean the glass thoroughly1 place in the oven or on the stove1 heat gradually until the glass just melts the cement1 rub the cement over both surfaces1 bring them together when the cement is fluid1 press them together to squeeze out as much cement as possible1 and keep them pressed together until the cement is hard4 ,cement a strip of wood to a strip of glass in the same way4 ,cement a strip of wood to a strip of glass with liquid glue1 both wood and glass being cold4 ,keep them pressed together until the glue is dry1 perhaps a day or two4 ,,magical ,,experiments ,boys1 you can perform many magic experiments with apparatus made out of the glass tubes1 rubber stoppers1 and rubber unions supplied with 8,experimental ,glass ,blowing40 ,we outline a number in the following pages4 ,you can invent many more for yourselves4 ,,magic ,,with ,,flames ,experiment #gj4 ,magic lighting4 ,light your alcohol lamp1 blow it out1 and bring a lighted match down toward the wick from above 7,fig4 #ic74 ,does the lamp light in a most magical manner before the match touches the wick8 ,illustration3 ,,fig4 #ic ,,magic ,repeat this with a kerosene lamp and with a candle4 ,do they light in the same magical manner8 ,the 8why0 of it ,when the lamp is lighted1 the alcohol or kerosene turns to a gas1 and it is the gas which burns2 when the candle is lighted1 the wax turns to an oil1 the oil turns to a gas1 and it is the gas which burns4 ,the gas rises from the wick for a short time after the flame is blown out1 and it is this gas which lights when you bring the match down toward the wick4 ,experiment #ga4 ,air used by flames4 ,illustration3 ,,fig4 #id ,,the ,,candles ,,go ,,out ,,and ,,the ,,water ,,rises ,drop melted candle wax on a tin can cover and attach the bottoms of two candles to the cover 7,fig4 #id72 use one candle about #d inches long and another about #c inches1 stand them upright in a pan of water1 light them1 and invert a wide-mouthed bottle over them4 ,does some air escape at first due to expansion1 do both candles go out1 the taller one first1 and does the water rise until the bottle is about one-fifth full8 ,illustration3 ,,fig4 #ie ,,the ,,cork ,,rises ,cut a piece of candle inch long1 float it on a flat cork or can cover in the pan of water1 light it1 and invert a fresh empty bottle over it 7,fig4 #ie74 ,is the result similar8 ,the 8why0 of it ,the water rises in the bottle because of the air is used up by the burning candle4 ,air is oxygen and nitrogen4 ,the oxygen unites with the burning gas of the candle and produces water vapor 7,h#b,o7 and carbon dioxide 7,,co#b72 the nitrogen takes no part in the burning4 ,illustration3 ,,fig4 #if ,,water ,,from ,,flame ,the water vapor 7,h#b,o7 condenses to water on cooling and takes up very little space4 ,the carbon dioxide remains a gas and occupies space1 but this is offset by the volume of the air which escaped at first4 ,the result is that the volume of gas at the end is about less1 and the atmospheric pressure on the water in the pan lifts water into the bottle4 ,the candle goes out because it must have oxygen to burn and the oxygen is used up4 ,experiment #gb4 ,water produced by fire4 ,it is certainly magic to produce water from fire1 but you can do it easily as follows3 ,hold a clean1 dry1 cold tumbler over your alcohol lamp flame 7,fig4 #if74 ,does water deposit in the form of mist on the inside of the tumbler8 ,illustration3 ,,fig4 #ig ,,atmospheric ,,pressure ,repeat with fresh tumblers with the flame of a kerosene lamp and of a candle4 ,are the results similar8 ,direct the blowpipe flame into the end of a piece of ,no4 #b or #d tubing4 ,does water deposit in drops inside the tube about #a inch above the end8 ,the 8why0 of it ,one of the chief constituents of alcohol1 kerosene1 and candle wax is hydrogen 7,h71 and when this burns in the oxygen 7,o7 of the air1 it produces water 7,h#b,o74 ,it is this water which condenses on the cold glass4 ,,magic ,,with ,,air ,experiment #gc4 ,atmospheric pressure4 ,arrange a ,no4 #f tube as in #a1 ,fig4 #ig1 and suck air out at the top4 ,does the water run uphill into your mouth8 ,hold your finger over the top and lift the tube out of the pail 7#b74 ,does the water remain in the tube8 ,fill a bottle with water to overflowing1 insert a ,no4 #b tube into your one-hole stopper1 insert the stopper into the mouth of the bottle 7#c7 without admitting air below the stopper1 and try to suck water out of the bottle4 ,do you find that you cannot do so8 ,illustration3 ,,fig4 #ih ,,water ,,driven ,,up ,,tube ,,by ,,atmosphere ,repeat 7#c7 with the bottle half full of air 7#d74 ,do you find that you can now suck part of the water out of the bottle1 and all of it if you admit air8 ,the 8why0 of it ,the atmosphere which surrounds the earth exerts a pressure of #ae pounds per square inch on everything at the earth's surface4 ,it exerts this pressure equally downward1 sidewise1 and upward4 ,it is this atmospheric pressure on the water in the pail 7#a7 which lifts the water into the tube when you decrease the pressure on the water in the tube by sucking out air and then water4 ,it is this pressure upward that supports the water in #b4 ,the water does not rise in #c because the atmosphere cannot exert pressure downward on the water in the bottle4 ,illustration3 ,,fig4 #ii ,a ,,fountain ,the rise of the water in #d is due to another fact1 namely1 that any gas expands when the pressure on it is decreased4 ,when you suck air out of the tube you decrease the pressure on the water in the tube and thereby on the air in the bottle2 the air then expands and lifts the water into your mouth4 ,experiment #gd4 ,great pressure of air4 ,with the apparatus ,fig4 #ih hold your finger over the lower end of the tube1 suck as much air as you can out of the tube1 pinch the coupling1 and remove your finger under water4 ,does the atmosphere drive water up the tube very rapidly and with great force8 ,illustration3 ,,fig4 #ajj ,,magic ,experiment #ge4 ,a fountain4 ,with the apparatus ,fig4 #ii suck as much air as you can out of the bottle1 pinch the coupling1 and open it under water4 ,does the atmosphere lift the water into the bottle and produce a beautiful fountain8 ,illustration3 ,,fig4 #aja ,,more ,,magic ,experiment #gf4 ,magic tumbler4 ,fill a tumbler with water1 cover it with a sheet of paper1 hold the paper on with your hand1 invert the tumbler1 and remove your hand 7,fig4 #ajj74 ,does the atmospheric pressure upward support the paper and water8 ,experiment #gg4 ,magic lift4 ,fill a tumbler with water1 press your palm down on the top with your fingers pointing downward 7,fig4 #aja71 straighten your fingers without admitting air to the tumbler1 and then lift your hand4 ,do you lift the tumbler of water also8 ,there is a partial vacuum between your hand and the water1 and the atmospheric pressure upward and downward holds your hand and the tumbler together4 ,illustration3 ,,fig4 #ajb ,,tumbler ,,pendulum ,experiment #gh4 ,a magic pendulum4 ,pass a string through a small hole in a piece of cardboard1 knot the end of the string1 and drop melted candle wax over the hole to make it air tight4 ,fill a tumbler with water1 press the cardboard down on the tumbler with the palm of your hand1 and lift the string4 ,do you also lift the tumbler 7,fig4 #ajb78 ,swing the tumbler gently as a pendulum4 ,illustration3 ,,fig4 #ajc ,,poultry ,,fountain ,experiment #gi4 ,a poultry fountain4 ,to make the poultry fountain 7,fig4 #ajc71 fill a bottle with water1 hold your thumb over the mouth1 invert the bottle over the pan of water1 and remove your thumb under water4 ,does the atmospheric pressure on the water in the pan hold the water in the bottle8 ,lift the bottle until the mouth is a little above the water in the pan4 ,does air enter and water run out until the mouth is again covered with water8 ,this is what happens when the poultry1 by drinking1 lower the water below the mouth of the bottle4 ,in a poultry fountain the bottle is supported1 as shown1 with its mouth under water but above the bottom4 ,illustration3 ,,fig4 #ajd ,a ,,drinking ,,fountain 7,from ,butler's ,household ,physics4 ,published by ,whitcomb ,barrows1 ,boston7 ,illustration3 ,,fig4 #aje ,,homemade ,,drinking ,,fountain ,experiment #hj4 ,a drinking fountain4 ,the drinking fountain 7,fig4 #ajd7 is similar in principle to the poultry fountain of the last experiment4 ,the water is held in the large inverted bottle by the atmospheric pressure on the water in the lower vessel4 ,air enters the bottle and water escapes from it when the level of the water in the lower vessel falls below the mouth of the bottle4 ,the water is cooled by the ice surrounding the lower vessel4 ,make a drinking fountain of this kind as in ,fig4 #aje1 ask a friend to hold it1 remove the glass plug from the coupling1 and draw a glass of water4 ,do you observe that air bubbles enter the inverted bottle and water flows from it only when the water level in the half bottle falls below the mouth of the inverted bottle8 ,allow the water to flow continuously4 ,is the water level practically constant in the half bottle until the upper bottle is empty8 ---------------------------------------- -------------------------------- ,,transcriber',s ,,notes ,typos fixed2 non-standard spelling and dialect retained4 ,enclosed italics font in underscores4 ,enclosed bold font in equals4 ,subscripts are shown using an underscore 77 with curly braces 1 as in ,h#b,o4