The classroom apparatus necessary for an effective, interesting presentation of hydrostatics includes: pressure tubes, manometer tubes, pressure syringe, Pascal\u27s vases and equilibrium tubes. All of these are listed in the apparatus catalogs found in every high school

Begeman, L.

University of Northern Iowa

Science Bulletin Volume 1 Number 3 Article 8 1-1929 Hydrostatics L. Begeman Iowa State Teachers College Follow this and additional works at: https://scholarworks.uni.edu/science_bulletin  Part of the Health and Physical Education Commons, and the Science and Mathematics Education Commons Let us know how access to this document benefits you Copyright ©1929 by Iowa State Teachers College Recommended Citation Begeman, L. (1929) "Hydrostatics," Science Bulletin: Vol. 1: No. 3, Article 8. Available at: https://scholarworks.uni.edu/science_bulletin/vol1/iss3/8 This Contents is brought to you for free and open access by UNI ScholarWorks. It has been accepted for inclusion in Science Bulletin by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. Offensive Materials Statement: Materials located in UNI ScholarWorks come from a broad range of sources and time periods. Some of these materials may contain offensive stereotypes, ideas, visuals, or language. 22 SCIENCE BULLETIN product. It is not easy to show with such small quantities of material that the starch has been changed to mal-tose. If you wish to create a real inter-est in the study of insects, try the cockroach for a semester. ROY L. ABBOTT Note: Live roaches may be obtained from N. P. Frye and Son, St. Peters-burg, Fla. HYDROSTATICS (Concluded) Physics The classroom apparatus necessary for an effective, interesting presenta-tion of hydrostatics includes: pres-sure tubes, manometer tubes, pres-sure syringe, Pascal's vases and equi-librium tubes. All of these are listed in the apparatus catalogs found in every high school. The total cost of such equipment need not exceed six or seven dollars. Some pieces can be m ade by the instructor. We use a pressure syringe made from the tloat of a toilet closet. Drill a number of small holes in the sphere, cut off the r od , solder on a tube six inches long and one inch in diameter , opening into the sphere. For a plunger wrap enough cord a round a wooden rod to fit the cylinder tightly. As an inter-esting lecture demonstration of Pas-cal's principle completely fill a thin-walled bottle with water and insert a close-fitting stopper. A sharp down-ward blow upon the stopper will completely shatter the bottle. The instructor should avail him-self of every opportunity to enliven the subject of Hydrostatics by dis-cussing the various devices in which the principles are practically ap-plied. These would include the hy-draulic press, hydraulic jacks, hy-draulic brakes of an automobile, bar-ber's chair, city wate r distributing systems, devices used to neutralize the pressure on divers, and those us-ed on engineering projects to enable m en to work in caissons subjected to ,vate r pressure. He may also profitably discuss the principles and applications of pres- . sure of flowing liquids. Take up Ber-nouilli's prii1ciple as illustrated in the common laboratory filte r pump and also ' in the curving of a pitched ball. The pdnciple ofTorricelli, which deals with the tlow of a liquid from an orifice when subjected to gravity pressure, may be studied. Some years ago the writer w as consulted by a group of m en as to whether the doubling of the height of the city water tank would d onble th e Jlow of the water from a faucet. vVhen he stated that, theoretically, the tank would have to be four times as high to double the tlow, the group were almost incredulous. The writer doubts that in the minds of those men, this statement adr!ed to his rep-utation as a teacher of physics. L. BEGEMAN WINTER STUDY OF TREES Botany One often h ears the idea expressed that there is little to be don e during the winte r months in the way of field or laboratory studies of t rees. In r eality ther e is a wealth of mater-ial available and the followin g sug-gestions are offered in the hope that they will be h elpful in ca lling atten-ti on to the possibilities of winter tree study. The annual shedding of leaves by our deciduous trees is familiar to all but the importance of this phenom-enon is not always r ecognized. The twigs of trees common to your local-ity can b e collected, or studied in the fi eld if the w eather permits. Atten-tion should b e directed to the corky covering of the twigs and to the dry, waterproof covering of the ' buds. The scars left by the dropping of the leaves are also covered by a corky tissue known as the abscission lay-er, which caused the severing of the leaf from the twig. The tree which during the summer showed a high evaporation rate due to its enormous leaf surface, ·now exposes a much smaller surface that is protected by corky tissue through which the es-cape of water is difficult. The im-portance of this protection is r ealiz-ed when we think of the frozen con-dition of the soil. The· waterproof nature of bud scales is readily illus-trated by buds of Boxelder, Cotton-wood, Shagbark Hickory and Horse Chestnut. It is insfructive to nofc that leaves were borne only on the portion of the twigs produced dur• ing the last season and also to notice · the position of the buds with r efe r~ ence to the leaf scars. H is interesting to ;compare • the winter condition ,of ·deciduous trees 

Hydrostatics

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Hydrostatics

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