Scientific Instruments

Chapter
Part of the History of Mechanism and Machine Science book series (HMMS, volume 12)

Abstract

Pendulums are used in various scientific instruments, either to make measurements, or to demonstrate scientific principles. Four of these uses are described in this chapter. These are Kater’s pendulum, Newton’s cradle, Foucault’s pendulum, and the Charpy impact testing machine. If the effective length, l, of a pendulum and the pendulum period, P, are known then the value of the acceleration due to gravity, g, can be calculated. The practical difficulty is the measurement of the effective length of a real pendulum. At the suggestion of F W Bessel in 1817 Captain Henry Kater of the British Army developed a reversible pendulum, known as Kater’s pendulum, whose effective length can be accurately determined. Kater’s pendulum, and subsequent refinements, were used for the determination of g until they were superseded by free-fall gravimeters in the 1950s. In its usual form, a Newton’s cradle, consists of five identical pendulums each with a hardened steel ball suspended by a pair of strings with the balls just in contact. If the ball at one end of the row is pulled back and released the impulse as it hits the next ball is transmitted along the row, and the ball at the other end flies off with the remaining balls remaining almost stationary. The Newton’s cradle has a long history. In 1662 Huygens pointed out that an explanation of its behaviour required conservation of both momentum and kinetic energy, although he did not use the latter term. Newton’s cradle is still used to demonstrate this point. The term is used because the foundations of mechanics, including conservation of momentum and kinetic energy were established by Isaac Newton in his Principia of 1687. Newton’s cradle is also an amusing toy. The Foucault pendulum was used by Léon Foucault to demonstrate the Earth’s rotation in 1851. Apart from their use in clocks the Foucault pendulum is probably the best known use of pendulums. There are examples in many museums around the World. A Foucault pendulum usually consists of a spherical steel bob suspended from a long steel wire, with a pointer mounted below the bob so that its motion can be easily followed. A Foucault pendulum can swing freely in any direction, and is a close approximation to a simple string pendulum. In a Charpy impact testing machine a swinging pendulum is used to fracture notched steel test pieces. The energy absorbed in breaking a notched test piece is a useful measure of a steel’s fracture toughness. Interest in the effects of impacts on metals dates back to the early nineteenth century. Impact testing of metals developed from the observation that metals are often more brittle under an impact than when loaded slowly. The earliest description of an impact test appears to be that given by Tredgold in 1822. He states: ‘The best and most certain test of the quality of a piece of cast iron, is to try it with a hammer; if the blows of the hammer make a slight impression, denoting some degree of malleability, the iron is of good quality, providing it be uniform; if fragments off, and no sensible indentation be made, the iron will be hard and brittle.’ The first use of a pendulum impact testing machine was by S Bent Russell in 1898, and by the beginning of the twentieth century the use of pendulum impact testing machines was well established. The pendulum impact testing machine developed by Georges Charpy in 1904 is the basis of the Charpy impact testing machines that are now extensively used world wide. Methods of test have been standardised, although there are some variations. Despites its importance the Charpy impact test is not usually mentioned by writers on pendulums.

Keywords

Test Piece Primary Mode Charpy Impact Rest Position Suspension Point 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. Anonymous (1989) Notched bar tests. Part 6. Method for precision determination of Charpy V-notch impact energies for metals (BS 131: Part 6: 1989). British Standards Institution, LondonGoogle Scholar
  2. Anonymous (1990a) Metallic materials – Charpy impact test – Part 1: Test method (V- and U-notches) (BS EN 10045–1: 1990). British Standards Institution, LondonGoogle Scholar
  3. Anonymous (1990b) Notched bar tests. Part 6. Specification for verification of the test machine used for precision determination of Charpy V-notch impact energies for metals (BS 131: Part 7: 1990). British Standards Institution, LondonGoogle Scholar
  4. Baker GL, Blackburn JA (2005) The pendulum. A case study in physics. Oxford University Press, OxfordMATHGoogle Scholar
  5. Barnard JG (1874) Problems of rotary motion presented by the gyroscope, the precession of the equinoxes, and the pendulum. Smithsonian Contrib Knowl 19(240):1–52Google Scholar
  6. Betrisey M (2010) Works of art that also tell the time. http://www.betrisey.ch/eindex.htm Accessed 20 July 2010
  7. Biggs WD (1960) The brittle fracture of steel. Macdonald and Evans Ltd., LondonGoogle Scholar
  8. Charpy G (1904) On testing metals by the bending of notched bars. Int J Fract 1984 25(4):287–305 (Trans from Mémoirs de la Societé de Ingénieurs Civil de France by Towers OL, McSweeney S)Google Scholar
  9. Condurache D, Martinual V (2008) Foucault pendulum-like problems: a tensorial approach. Int J NonLinear Mech 438:743–760CrossRefGoogle Scholar
  10. Frost NE, Marsh KJ, Pook LP (1974) Metal fatigue. Clarendon, OxfordGoogle Scholar
  11. Gere JM, Timoshenko SP (1991) Mechanics of materials. 3rd SI edn. Chapman and Hall, LondonGoogle Scholar
  12. Hutzler J, Delaney G, Weaire D, MacLeod F (2004) Rocking Newton’s cradle. Am J Phys 72(12):1508–1516CrossRefGoogle Scholar
  13. Lamb H (1923) Dynamics, 2nd edn. Cambridge University Press, CambridgeMATHGoogle Scholar
  14. Matthews RJ (2000) Time for science education. How teaching the history and philosophy of pendulum motion can contribute to science literacy. Kluwer Academic/Plenum Publishers, New YorkGoogle Scholar
  15. Matthys R (2004) Accurate clock pendulums. Oxford University Press, OxfordCrossRefGoogle Scholar
  16. Phillips N (2005) What makes the Foucault pendulum move among the stars? In: Matthews MR, Gauld CF, Stinner A (eds) The pendulum. Scientific, historical and educational perspectives. Springer, Dordrecht, pp 38–44Google Scholar
  17. Pippard AB (1988) The parametrically maintained Foucault pendulum and its perturbations. Proc R Soc Lond A 420:81–91MATHCrossRefGoogle Scholar
  18. Rawlings AL (1993) The science of clocks and watches, 3rd edn. British Horological Institute Ltd., UptonGoogle Scholar
  19. Schultz-DuBois EO (1970) Foucault pendulum experiment by Kamerlingh Onnes and degenerate perturbation theory. Am J Phys 38(2):173–188CrossRefGoogle Scholar
  20. Siewert TA, Manahan MP, McCowan CN, Holt JH, Marsh FJ, Ruth EA (2000) The history and importance of impact testing. In: Siewert TA, Manahan MP (eds) Pendulum impact testing: a century of progress. STP 1380. American Society for Testing and Materials, West Conshohocken, pp 3–16Google Scholar
  21. Synge JL, Griffith BA (1959) Principles of mechanics, 3rd edn. McGraw Hill Book Company Inc., New YorkGoogle Scholar
  22. Tipper CF (1962) The brittle fracture story. Cambridge University Press, CambridgeGoogle Scholar
  23. Tobin W (2003) The life and science of Lon Foucault. The man who proved that the earth rotates. Cambridge University Press, CambridgeGoogle Scholar
  24. Tobin W, Pippard B (1994) Foucault, his pendulum and the rotation of the earth. Interdiscip Sci Rev 19(4):326–337Google Scholar
  25. Torge W (1980) Geodesy, an introduction. De Gruyter, Berlin (Trans by Jekeli C)Google Scholar
  26. Tóth L, Rossmanith H-P, Siewert TA (2002) Historical background and development of the Charpy test. In: François D, Pineau A (eds) From Charpy to present impact testing. Elsevier, Amsterdam, pp 319 (Charpy Centenary Conference (2001: Poitiers, France))Google Scholar
  27. Tredgold T (1822) A practical essay on the strength of cast iron, intended for the assistance of engineers, iron masters, architects, millwrights, founders, smiths, and others engaged in the construction of machines, buildings, etc, containing practical rules, tables and examples; also an account of some new experiments, with an extensive table of the properties of materials. Taylor J, LondonGoogle Scholar
  28. Zevin AA, Filonenko LA (2007) A qualitative investigation of the oscillations of a pendulum with a periodically varying length and a mathematical analysis of a swing. J Appl Math Mech 71(6):892–904MathSciNetCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.KentUK

Personalised recommendations