Main Index

Your Pocket Scientific Calculator
8 Sexagesimal - hours (or degrees), minutes and seconds


We can divide hours (or degrees) into minutes and seconds. Sixty seconds make a minute and sixty minutes make an hour (or a degree). This is a sexagesimal system, based upon 60. Although Man has counted in tens for at least seven thousand years (why? because he has ten fingers!), there are many advantages in using other bases for measuring. The Ancient Babylonians were using a sexagesimal system more than four thousand years ago. This is more fully discussed on the Page on Bases.

Do not confuse a sexagesimal system (base 60, from the Latin for six times ten) with a hexadecimal system (base 16, from the Greek for six plus ten). Many calculators allow you to work in hexadecimal.

In what follows I use hours and degrees interchangeably.The sexagesimal key is the SexG.gif - 327 bytes key. To convert hours into hours, minutes and seconds you just enter the hours (remember to press the = key to enter the number!) and then press the sexagesimal key. Try 16.579 - this gives the answer in hours minutes and seconds and decimal seconds. Pressing the sexagesimal key again turns a sexagesimal number back into hours and decimal hours.

To enter a number in sexagesimal key in the hours, then the sexagesimal key, then the minutes, then the sexagesimal key again, and then the seconds, then the sexagesimal key again, and finally the = key. You must enter the hours and minutes even if they are zero, but you do not have to enter zero seconds. The hours minutes and seconds must be numbers, not expressions, but can be more than sixty and include decimals. Try 6.27 hours, 108.63 minutes, 126.9 seconds. But however you enter them the answer will always be a whole number of hours and minutes, and the minutes and seconds will always be less than sixty.

The only SI unit of time is the second. To convert 18432 seconds to hours, minutes and seconds we just use the sexagesimal key with zero hours and minutes; to hours and decimal hours press the sexagesimal key again (or just divide the seconds by 3600 which is probably quicker and easier).

The only SI unit of angular measurement is the radian, this is discussed on the Page on Circles.

back

© Barry Gray April 2014