PDC Test - In the Beginning
You can earn 0.25 PDC by passing the exam following this article, which has been approved for publication by NCRA's Council of the Academy of Professional Reporters.
The questions are based on the material in the article but some may require additional research. Send your answer sheet to NCRA's Continuing Education Office, 8224 Old Courthouse Road, Vienna, VA 22182, and enclose a check for $40 (member) or $50 (non-member) to cover the processing fee.
In the Beginning
by Renée Cohen
You can't necessarily put your finger on what time is, and yet it probably rules your life. It has no conceivable beginning or end and so it defies placement in time, and yet it progresses on and on. How can a concept like time be so resistant to definition and boundaries, and simultaneously be so commonplace, so central to daily life?
Human conceptions of time and timekeeping methods have evolved quite dramatically over time, weaving this story. But has our relationship with time become so intense that our clocks are really more precise than the rotations of the earth these days?
As with anything in human history, our ancestors had far less complicated methods of telling time. According to modern accounts, there was originally nighttime, which was dark, and daytime, which was light. Human circadian rhythms and sight worked such that our ancestors had internal and external motivations for being diurnal (as opposed to nocturnal) creatures. Activities may have varied according to the day's temperatures and other creatures' patterns, but for the most part, it was either night or it was day.
This distinction between night and day probably didn't take long to lead to tracking shadows and the realization that shadows would trail across the ground, never hitting the same object twice in a light period or day. This discovery led to primitive sundials which could chart each day's exact noontime according to the earth's rotations around the sun. As seasons changed, sundials could always keep track of noon, but since the hours in each day varied, they could not measure consistent hours throughout the seasons. As society came to demand more consistent timekeeping for the purposes of business, travel and leisure, timekeepers evolved. The Greeks created hourglasses to keep political speeches concise (or just short!), and other Europeans used markings on their candles to measure the passage of hours as the wax burned through the night. Some societies made use of water clocks, which dripped water at a relatively consistent speed, and, therefore, would fill containers at consistent rates. Still, all of these timekeeping methods became obsolete as they were too maintenance intensive for the people who employed them.
Monastery bells became central timekeepers in many locations. Later they were succeeded by the first mechanical clocks, which appeared around the 13th century. At the time they were created, however, the memory of the bell ringing system was still fresh in the minds of the clock inventors, and so the German word glocke, which means bell, is where we get the English word "clock."
The earliest clocks had only one hand and all 24 hours on their faces, with noon being at the top and midnight at the bottom. In order to make the clocks increasingly precise, however, they were simplified to display only 12 hours at a time, like our modern analog timepieces. From this came the divisions of a.m. and p.m., or antemeridian and postmeridian, which are reminiscent of the sundials which measured shadows before and after their meridian lines. The 12-hour clock face also meant that the minutes could be read roughly with the hour hand. But again, this became too imprecise, and the minute and then the second hands were added.
Still, mechanical clocks were not perfectly accurate, and over the period of hours, days and weeks, the subtleties simply added up to different times on different watches, which defeated the basic purpose of keeping track of time in the first place.
After centuries of winding and setting mechanical and battery-powered clocks, digital watches with startling precision were invented. They read time according to the microscopic vibrations of tiny quartz crystal structures at the molecular level. This greatly improved the precision and reliability of timekeeping, as quartz-reliant digital watches are based on the 32,768 vibrations per second that quartz molecules make. (Each time the timepiece measures this number of vibrations, it registers that one second has passed.)
As if that were not exact enough, humans have continually pressed on to define time even more precisely. Now we have atomic clocks, which measure time similarly to digital clocks. However, atomic clocks use atoms, as their name would suggest, and not molecules. This enables us to tell time according to the billions of vibrations per second that an electron has, as opposed to the thousands of molecular vibrations.
Beyond that, scientists measure the movement of atoms' nuclei to reach the precision of pico- (trillionths) and femoseconds (thousandths of trillionths), which, for reference, are so inconceivably small that the number of femoseconds in one second outnumbers the number of seconds in 31 million years. Clocks that rely on such precise atomic movements to measure time are said to be more precise measures of time than the actual rotations of the earth.
Let's consider what this means. We can keep a watch so stable that it actually surpasses the precision of our planet's orbit. We can tell time that more than accounts for the geologic subduction zones that make continents creep around the tectonic plates, the earth's minute expansions and contractions, even the lunar gravitational pulls. And still, amidst all of the challenges we humans face, we continue the search for more perfect timepieces.
About the Author
Renee Cohen is a JCR Contributing Editor.
In the Beginning Exam
- Why are there seven days of the week?
- In the 13th century, seven was a lucky number.
- When the days of the week were named, folks only knew of seven planets. Had they known about Uranus, Neptune and Pluto, we might have more!
- Seven is the number of Greek gods associated with time.
- Political leaders from seven countries were responsible for naming the days.
- Friction and gravitational forces from the moon are slowing the earth down by .0016 seconds each century, so days are becoming longer.
- December is named according to the Latin word decem, which means 10.
- A.m. and p.m. were invented before primitive sundials.
- Diurnal means:
- awake for eight or more hours per day
- active in the daylight hours
- Centrally located hourly bell ringing was succeeded by the use of:
- mechanical clocks
- analog watches
- The evolution of timekeeping is not related to:
- leisure time
- basket weaving
- A nanosecond is ____ of a second.
- more than a minute
- We are capable of keeping time so precise that after 30 million years, the clock will only be off by about:
- one second
- one minute
- an hour
- 1/100th of a second
- Digital watches rely on:
- planetary rotations
- crystal vibrations
- atomic movements
- The English word clock comes from the:
- Swiss word for watch
- Greek god of time
- German word for bell
- Latin word for monastery
- A.m. means
- before dark
- before midnight
- after morning
- before noon
- Sundials accurately kept track of:
- The precision of atomic clocks relies on the movements of:
- salt particles
- Time is one of the world's deepest mysteries.
- The world is divided into _______ time zones.
- According to _____, we now know time as the Fourth Dimension.
- Benjamin Franklin
- Thomas Edison
- Isaac Newton
- Albert Einstein
- Electronic watches are not able to:
- store information
- serve as calculators
- serve as game boards
- encode captions
- Spring-driven clocks never need winding.
- Natural patterns of activity for plants and animals are referred to as:
- circadian rhythms
- geological eras
- time capsules