They are known as "parallels" of latitude, because they run parallel to the equator. One simple way to visualize this might be to think about having imaginary horizontal "hula hoops" around the earth, with the biggest hoop around the equator, and then progressively smaller ones stacked above and below it to reach the North and South Poles. Can you think of other ways to visualize the parallels of Latitude?
Think about having imaginary horizontal "hula hoops" around the earth, with the biggest hoop around the equator, and then progressively smaller ones stacked above and below it to reach the North and South Poles.
Latitude lines are a numerical way to measure how far north or south of the equator a place is located. The equator is the starting point for measuring latitude--that's why it's marked as 0 degrees latitude.
Longitude , the lines that run up and down on a map or globe, is always listed second when assigning a measurement. The E or the W following a longitude measurement indicate whether the degrees are measured east or west of the prime meridian.
Minutes and seconds sometimes follow latitude and longitude measurements to more accurately pinpoint a location. Each degree can be divided into sixty minutes, usually indicated by a single quotation mark ex. However, until the advent of a clock which was reliable at sea, it was extremely difficult to know the time back at Port A when you were on Ship B. Clocks of the 17th and 18th centuries were unreliable at sea.
In fact, few clocks of the time were reliable in the way we assume clocks to be today. The pendulum clock, invented in , was an improvement in accurate timekeeping compared with the verge escapement mechanism clocks with Foliot or balance-wheel timekeepers which had been in fashion since the 14th century.
Pocket watches were in their infancy in the 17th century but until the balance spring was added to the balance wheel of pocket watches in the midth century, the pendulum clock was the most advanced timekeeper of the age.
The motion of a ship was the main issue preventing a pendulum clock in the 18th century from keeping time at sea.
A pendulum would not swing consistently to keep time while a ship was pitching and yawing on the open seas. John Harrison was the first inventor to work towards a viable solution to this problem. With an angle of longitude and an angle of latitude, we can locate any point on the surface of the earth. You've seen lines running across maps your whole life and may not have noticed them. The lines running North to South are called "Meridians" or "lines of longitude" Figure 2 , while the lines running East to West are called "Parallels" or "lines of latitude" Figure 3.
Figure 2. Meridians or "Lines of Longitude" and degree readings for longitudes in increments of 30 degrees.
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