Thinking of the Babylonians had base 60 system, the first reason I can come up with is that they might find base 10 system too small and have fewer factors than 60. 60s are commonly used in our daily life. For example, an hour has 60 minutes, and a minute has 60 seconds. This hour system has been used for a long time. Angles are also related to 60. A circle is divided into 360 degrees, which is 6 times 60. The longitude of the earth is also divided into 360 degrees, which is also related to 60. China has 12 animals and 5 elements for the zodiac. 12 times 5 is 60. This could also be the relationship with the base 60 system.
Research shows that my guess is somehow correct. More factors for 60 can have a lot of flexibility for fractions and can make calculations easier. Also, finger-joint counting allows people to count to 12 with a single hand. This means that five repeated hand counts give 60.
Hi Sally, nice speculation here about the role of base 60 in time and geometry. I am left curious about your thoughts on how you might explore these ideas with students.
ReplyDeleteI can do a hands-on counting activity with students:
DeleteTeach students the finger-joint counting method. Have them practice counting to 12 with one hand and to 60 with both hands. Or perhaps the base 2 counting system. Discuss the practicality of this method in ancient times and how it may have influenced the choice of a base-60 system.