The Science Notebook
Gilbert Glass Blowing - Part III

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NOTE:  This book was published in as a manual to accompany the Gilbert Glassblowing Set as part of the "Boy Engineering" Series.  the exact copyright date is unknown, although based on information from "The Internet Archive" it is believed that this publication is in the public domain.  Many today would not consider glassblowing to be a safe activity for young people.    Therefore, this book is probably best appreciated for its historical value rather than as a source for current information and good experiments.  If you try anything here, please understand that you do so at your own risk.  See our Terms of Use.

Pages 28 - 35


because the tube tends to cave in on the inside of the bend (2) or flatten on the outside (3), or both.

Make the bend as follows: Heat a piece of No. 2 tube about 2 inches from one end in the lamp flame, turn it constantly and move it back and forth endwise to heat a length of about 2 1/2 inches. When soft, take the tube out of the flame, and bend the ends upward until the angle is 90.

If the bend is flat on the inside or outside, close one end of the tube in the blowpipe flame, smooth the other end and allow them to cool, then heat the flat side of the bend in the blowpipe flame and blow it out slightly.

This makes the diameter of the tube at the bend equal to that of the remainder of the tube. Cut off the closed end, smooth
the edge, and your bend is complete.

Make bends with No. 4 tube.

Experiment 30. To make a drinking tube.

Many times when there is sickness in the house, it is convenient to have a glass drinking tube (Fig. 42), through which the patient can drink without raising his head.

Make such a tube from a piece of No. 4 tubing. The short arm is equal in length to the depth of the tumbler; the long arm, or mouthpiece, is about 1 inch longer than this.

Experiment 31. To make a siphon.

Cut off a piece of No 1 tubing 8 inches long, make 


two right-angled bends about 1 inch apart at the center, smooth both ends, and your siphon is complete (Fig. 43).

Experiment 32. Magic.

Put one arm of the siphon in a tumbler of water and suck air out of the other end. Does the water start running and does it continue to run in a most magical way (Fig. 44) until the water is below the end of the siphon in the tumbler?

Fill the tumbler with water again, start the water running, put the outer arm of the siphon in an empty tumbler, and stand both tumblers on the table (Fig. 45). Does the water run up one arm of the siphon and down

the other into the empty tumbler? Does it stop running when the levels are the same? Stand the first tumbler on a book. Does the water run again and stop when the levels are again the same (Fig. 46)?

Place the lower tumbler on the book and the upper tumbler on the table. Does the water now run in the opposite direction until the levels are again the same?

Raise one tumbler a foot or so above the table. Does the water run up over the edge and drop into the second? Now before the upper tumbler is empty, lower it in such a way that an arm of the siphon is in each tumbler, and raise the second
tumbler. Does the water now run in the opposite direction?


You boys who have the Gilbert set on "Hydraulic and Pneumatic Engineering" 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 way.

Experiment 33. A long-armed siphon.

Attach a full length of No. 4 tube to each arm of the siphon, as in Fig. 47, and repeat the experiments described above.

Note: When you insert a glass tube into a rubber coupling or rubber stopper, wet the end of the glass tube and the inside of the coupling or stopper, grasp the tube near the end to be inserted, and insert with a twisting motion.

Experiment 34. To make a nozzle.

Attach a working handle to one end of a piece of No. 2 tube, heat the tube about one inch from the end in the lamp flame, turn constantly until soft, tken remove from the flame, and dra>w it out about 3 inches. When cool, break off the thin tube, cut off the nozzle to a length of about 2 1/2 inches, smooth the large end, and your nozzle (Fig. 48) is complete.

Experiment 35. To make a fountain.

Arrange the apparatus as in Fig. 49, and


suck air out of the nozzle. Have you made a beautiful fountain?

Experiment 36. Magic.

Make a nozzle 6 inches long out of No. 2 tube. Smooth the ends of the nozzle, and long tubes. Arrange the apparatus as in Fig. 50 and suck air out of the nozzle until the water runs in the siphon. Does the water squirt out of the nozzle in a magical manner?

Experiment 37. More magic.

Arrange the No. 2 apparatus as in Fig. 51, with the nozzle inside the bottle. Now to start the apparatus: Fill the bottle about quarter full of water, insert the tubes in the stopper as shown; insert the stopper into the mouth of the bottle; invert the bottle; then put the short tube in a tumbler full of water and the long tube


in an empty pail or basin. Is there a magical fountain inside the bottle?

Repeat this with a taller bottle, if you can find one to fit your two-hole stopper. Do you get a higher fountain?

Experiment 38. Still more magic.

Make another nozzle and attach it to the apparatus used in the last experiment by means of the inverted siphon (Fig. 52).

Start the experiment as described above. Do you get two fountains?

Experiment 39. To start a siphon.

You can start a siphon without sucking the air out of it as follows: Fill the siphon with water, put a finger over each end (1, Fig. 53), place one end in a tumbler full of water and remove the finger under water (2, Fig. 53), then remove the other finger. Does the siphon start?

In this case the water you pour into the siphon drives the air out, and this is the reason you do not need to suck the air out.


Experiment 40. To siphon sand or mud.

Arrange a siphon (Fig. 54), start the water flowing, and then pour sand or mud into the upper tumbler. Is the sand or mud siphoned over into the lower tumbler?

Attach a long tube to the outer arm of the siphon and repeat the experiment. Is the sand or mud siphoned more rapidly and more thoroughly?

Experiment 41. To make a squirt bottle.

Make a nozzle at one end of a piece of No. 2 tubing, make a bend near the nozzle, cut off the other end at such a length that it will reach to within 1/4 inch of the bottom of the bottle, smooth this end, allow it to cool; wet the tube and the two-hole stopper, shove it through one hole of the stopper, insert an elbow in the other hole, and your squirt bottle is complete (Fig. 55).

Fill the bottle with


water, and blow through the elbow. Do you get a fine long stream from the nozzle (Fig. 56)?

Experiment 42. To make a trick squirt bottle.

You can have any amount of fun with a trick squirt bottle. It is exactly the same as the squirt bottle described in Experiment 41 except that it has a hole just below the bend (Fig. 57).

To make the hole, make the long bent nozzle as in the last experiment, then heat the tube just below the bend in the blowpipe flame, touch a piece of glass tube to the red-hot glass (1, Fig. 58), and pull it away (2, Fig. 58). Do you find that the hot glass is pulled out into a thin pointed tube? Break off the thin tube close to the large tube, heat in the blowpipe flame until the edges are smooth and at the same level as the sides of the large tube. Flare the edges of the hole, if necessary; it should be about 1/8 inch in diameter.

Now fill the bottle with water, and blow


hard (Fig. 59). Do you find that one stream of water is driven into your face and another out of the nozzle? 

Experiment 43. Fun with a trick squirt bottle.

Now to have fun with your trick bottle, show it to one friend at a time. Do not ask him to try the bottle, just go where he can see you and squirt a long stream, but unknown to him have your finger over the hole below the bend. Your friend will just naturally want to have a try at it. So you say "All right, let's see who can squirt the longest stream." Tell him that all he has to do is to take a deep breath and blow as hard as he can. He will do so, with laughable results (Fig. 60).

Now together find another friend. Do not ask him to blow, but each of you blow as long a stream as you can, where

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