Robert J. Matthys
- Published in print:
- 2004
- Published Online:
- January 2010
- ISBN:
- 9780198529712
- eISBN:
- 9780191712791
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198529712.001.0001
- Subject:
- Physics, History of Physics
The Shortt clock, made in the 1920s, is the most famous accurate clock pendulum ever known, having an accuracy of one second per year when kept at nearly constant temperature. Almost all of a ...
More
The Shortt clock, made in the 1920s, is the most famous accurate clock pendulum ever known, having an accuracy of one second per year when kept at nearly constant temperature. Almost all of a pendulum clock's accuracy resides in its pendulum. If the pendulum is accurate, the clock will be accurate. This book describes many scientific aspects of pendulum design and operation in simple terms with experimental data, and little mathematics. It has been written, looking at all the different parts and aspects of the pendulum in great detail, chapter by chapter, reflecting the degree of attention necessary for making a pendulum run accurately. The topics covered include the dimensional stability of different pendulum materials, good and poor suspension spring designs, the design of mechanical joints and clamps, effect of quartz on accuracy, temperature compensation, air drag of different bob shapes and making a sinusoidal electromagnetic drive. One whole chapter is devoted to simple ways of improving the accuracy of ordinary low-cost pendulum clocks, which have a different construction compared to the more expensive designs of substantially well-made ones. This book will prove invaluable to anyone who wants to know how to make a more accurate pendulum or pendulum clock.Less
The Shortt clock, made in the 1920s, is the most famous accurate clock pendulum ever known, having an accuracy of one second per year when kept at nearly constant temperature. Almost all of a pendulum clock's accuracy resides in its pendulum. If the pendulum is accurate, the clock will be accurate. This book describes many scientific aspects of pendulum design and operation in simple terms with experimental data, and little mathematics. It has been written, looking at all the different parts and aspects of the pendulum in great detail, chapter by chapter, reflecting the degree of attention necessary for making a pendulum run accurately. The topics covered include the dimensional stability of different pendulum materials, good and poor suspension spring designs, the design of mechanical joints and clamps, effect of quartz on accuracy, temperature compensation, air drag of different bob shapes and making a sinusoidal electromagnetic drive. One whole chapter is devoted to simple ways of improving the accuracy of ordinary low-cost pendulum clocks, which have a different construction compared to the more expensive designs of substantially well-made ones. This book will prove invaluable to anyone who wants to know how to make a more accurate pendulum or pendulum clock.
Robert James Matthys
- Published in print:
- 2004
- Published Online:
- January 2010
- ISBN:
- 9780198529712
- eISBN:
- 9780191712791
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198529712.003.0001
- Subject:
- Physics, History of Physics
This chapter deals with simple pendulums and with several things that can be done to improve their accuracy. Most of the items have only a minor effect on accuracy, but they add up. The pendulum ...
More
This chapter deals with simple pendulums and with several things that can be done to improve their accuracy. Most of the items have only a minor effect on accuracy, but they add up. The pendulum should be enclosed in a case to protect it from the air currents of an open room, which will push the pendulum around and give erratic timing. A metal pendulum rod is recommended over a wooden one. If the pendulum is not temperature compensated, a low thermal expansion metal like iron must be chosen for the pendulum rod. If the pendulum is not temperature compensated, the bob must be supported at its bottom edge rather than at its middle or top edge. Other tips: use a low drag bob shape, walls dose to the pendulum cause a problem with relative humidity; slide the top end of the suspension spring up and down through a narrow slot; keep the number of piece parts and mechanical joints in a pendulum to a minimum.Less
This chapter deals with simple pendulums and with several things that can be done to improve their accuracy. Most of the items have only a minor effect on accuracy, but they add up. The pendulum should be enclosed in a case to protect it from the air currents of an open room, which will push the pendulum around and give erratic timing. A metal pendulum rod is recommended over a wooden one. If the pendulum is not temperature compensated, a low thermal expansion metal like iron must be chosen for the pendulum rod. If the pendulum is not temperature compensated, the bob must be supported at its bottom edge rather than at its middle or top edge. Other tips: use a low drag bob shape, walls dose to the pendulum cause a problem with relative humidity; slide the top end of the suspension spring up and down through a narrow slot; keep the number of piece parts and mechanical joints in a pendulum to a minimum.
