View source for Physics:Six-hour clock

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The '''six-hour clock''' is a traditional timekeeping system used in the [[Social:Thai language|Thai]] and formerly the [[Social:Lao language|Lao language]] and the [[Social:Khmer language|Khmer language]], alongside the official [[Physics:24-hour clock|24-hour clock]]. Like other common systems, it counts twenty-four [[Hour|hour]]s in a day, but divides the day into four quarters, counting six hours in each. The hours in each quarter (with the exception of the sixth hour in each quarter) are told with period-designating words or phrases, which are:

*... ''mong chao'' ({{lang-th|...โมงเช้า}}, {{IPA-th|mōːŋ tɕʰáːw|}}) for the first half of daytime (07:00 to 11:59)
*''Thiang'' ... (เที่ยง) for 12:00 to 12:59
*''Bai'' ... ''mong'' ({{lang|th|บ่าย...โมง}}, {{IPA|[bàːj mōːŋ]}}) for the latter half of daytime (13:00 to 18:59)
*... ''thum'' ({{lang|th|...ทุ่ม}}, {{IPA|[tʰûm]}}) for the first half of nighttime (19:00 to 23:59)
*''Thiang Khuen'' (เที่ยงคืน) 24:00
*''Ti'' ... ({{lang|th|ตี...}}, {{IPA|[tīː]}}) for the latter half of nighttime (01:00 to 06:59)

These terms are thought to have originated from the sounds of traditional timekeeping devices. The [[Biology:Gong|gong]] was used to announce the hours in daytime, and the drum at night. Hence the terms ''mong'', an onomatopoeia of the sound of the gong, and ''thum'', that of the sound of the drum. ''Ti'' is a verb meaning ''to hit or strike'', and is presumed to have originated from the act of striking the timekeeping device itself.<ref name="Unlocked">{{citation|last=Thongprasert|first=Chamnong|chapter=ทุ่ม-โมง-นาฬิกา (Thum-Mong-Nalika)|title=ภาษาไทยไขขาน (Thai Unlocked)|publisher=Prae Pitaya Press|place=Bangkok|year=1985|pages=229–237|url=http://www.royin.go.th/th/knowledge/detail.php?ID=1273|deadurl=yes|archiveurl=https://web.archive.org/web/20090726014744/http://www.royin.go.th/th/knowledge/detail.php?ID=1273|archivedate=2009-07-26|df=}}. {{th icon}}</ref> ''Chao'' and ''bai'' translate as ''morning'' and ''afternoon'' respectively, and help to differentiate the two daytime quarters.

The sixth hours of each quarter are told by a different set of terms. The sixth hour at dawn is called ''yam rung'' ({{lang|th|ย่ำรุ่ง}}, {{IPA|[jâm rûŋ]}}), and the sixth hour at dusk is called ''yam kham'' ({{lang|th|ย่ำค่ำ}}, {{IPA|[jâm kʰâm]}}), both references to the act of striking the gong or drum in succession to announce the turning of day (''yam''), where ''rung'' and ''kham'', meaning ''dawn'' and ''dusk'', denote the time of these occurrences. The midday and midnight hours are respectively known as ''thiang'' ({{lang|th|เที่ยง}}, {{IPA|[tʰîaːŋ]}}, or ''thiang wan'', {{lang|th|เที่ยงวัน}}, {{IPA|[tʰîaːŋ wān]}}) and ''thiang khuen'' ({{lang|th|เที่ยงคืน}}, {{IPA|[tʰîaːŋ kʰɯ̄ːn]}}), both of which literally translate as ''midday'' and ''midnight''.

Midnight is also called ''song yam'' ({{lang|th|สองยาม}}, {{IPA|[sɔ̌ːŋ jāːm]}}; note that ''yam'' is a different word), a reference to the end of the second three-hour period of the night watch (''song'' translates as the number ''two''). In addition, ''hok (6) thum'' and ''ti hok'' may also be used to refer to the hours of midnight and dawn, following general usage for the other hours, although more rarely; and the fourth to sixth hours of the second daytime half may also be told as ...''mong yen'' ({{lang|th|...โมงเย็น}}, {{IPA|[mōːŋ jēn]}}), ''yen'' meaning ''evening''.

The system has been used in some form since the days of the [[History:Ayutthaya Kingdom|Ayutthaya Kingdom]],{{citation needed|date=February 2009}} but was codified similarly to its present form only in 1901 by King Chulalongkorn in ''Royal Gazette'' 17:206.<ref>{{citation|title=ประกาศใช้ทุ่มโมงยาม|periodical=Royal Gazette|date=29 July 1901|issue=17|page=206|url=http://www.ratchakitcha.soc.go.th/DATA/PDF/2443/018/206.PDF|accessdate=2008-10-18}}. {{th icon}}</ref> Nowadays, it is used only in colloquial speech. However, a corrupted form of the six-hour clock is more frequently encountered,<ref name="Unlocked" /> where usually the first half of daytime (including the sixth hour of the preceding quarter) is counted as in the twelve-hour clock, i.e. ''hok (6) mong chao'', ''chet (7) mong'', etc., up to ''sip et (11) mong''.

The six-hour clock system was abolished in Laos and Cambodia during the French protectorate, and the French 24-hour clock system (for example, 3h00) has been used.

A comparison of the systems is as follows:

{| class="wikitable"
! rowspan="2"| Meaning || colspan="2" | 6-hour || colspan="2" | Modified 6-hour || rowspan="2"| 24-hour || rowspan="2"| 12-hour 
|- 
! Thai || [[Social:Royal Thai General System of Transcription|RTGS]] || Thai || RTGS
|-
| 1 early morning || ตีหนึ่ง || ''ti nueng'' || ตีหนึ่ง  || ''ti nueng'' || 01:00 || 1:00 am
|-
| 2 early morning|| ตีสอง || ''ti song'' || ตีสอง || ''ti song'' || 02:00 || 2:00 am
|-
| 3 early morning|| ตีสาม  || ''ti sam''  || ตีสาม || ''ti sam'' || 03:00 || 3:00 am
|-
| 4 early morning || ตีสี่ || ''ti si''  || ตีสี่ || ''ti si'' || 04:00 || 4:00 am
|-
| 5 early morning|| ตีห้า || ''ti ha''  || ตีห้า || ''ti ha'' || 05:00 || 5:00 am 
|-
| 6 in the morning|| ตีหก,<br>ย่ำรุ่ง || ''ti hok'',<br>''yam rung'' || หกโมงเช้า || ''hok mong chao'' || 06:00 || 6:00 am
|- style="background:#EEEEEE;"
| 1 in the morning || โมงเช้า || ''mong chao'' || เจ็ดโมง (เช้า)<sup>*</sup> || ''chet mong (chao)''<sup>*</sup> || 07:00 || 7:00 am
|- style="background:#EEEEEE;"
| 2 in the morning || สองโมงเช้า  || ''song mong chao'' || แปดโมง (เช้า)<sup>*</sup> || ''paet mong (chao)''<sup>*</sup>|| 08:00 || 8:00 am
|- style="background:#EEEEEE;"
| 3 in the morning || สามโมงเช้า  || ''sam mong chao'' || เก้าโมง (เช้า)<sup>*</sup> || ''kao mong (chao)''<sup>*</sup> || 09:00 || 9:00 am
|- style="background:#EEEEEE;"
| 4 in the morning || สีโมงเช้า || ''si mong chao'' || สิบโมง (เช้า)<sup>*</sup> || ''sip mong (chao)''<sup>*</sup> || 10:00 || 10:00 am
|- style="background:#EEEEEE;"
| 5 in the morning || ห้าโมงเช้า || ''ha mong chao'' || สิบเอ็ดโมง (เช้า)<sup>*</sup> || ''sip et mong (chao)''<sup>*</sup> || 11:00 || 11:00 am
|- style="background:#EEEEEE;"
| midday|| เที่ยงวัน || ''thiang wan'' || เที่ยงวัน || ''thiang wan'' ||  12:00 || 12:00 pm
|-
| 1 in the afternoon || บ่ายโมง || ''bai mong'' || บ่ายโมง || ''bai mong'' || 13:00 || 1:00 pm
|-
| 2 in the afternoon || บ่ายสองโมง || ''bai song'' ''mong'' || บ่ายสองโมง || ''bai song mong'' || 14:00 || 2:00 pm
|-
| 3 in the afternoon || บ่ายสามโมง || ''bai sam'' ''mong'' || บ่ายสามโมง || ''bai sam mong'' || 15:00 || 3:00 pm
|-
| 4 in the afternoon || บ่ายสี่โมง || ''bai si'' ''mong'' || บ่ายสี่โมง<sup>**</sup> || ''bai si mong''<sup>**</sup> || 16:00 || 4:00 pm
|-
| 5 in the afternoon || บ่ายห้าโมง || ''bai ha'' ''mong'' || บ่ายห้าโมง<sup>**</sup> || ''bai ha mong''<sup>**</sup> || 17:00 || 5:00 pm
|-
| 6 in the evening || หกโมงเย็น,<br>ย่ำค่ำ || ''hok mong yen'',<br>''yam kham'' || หกโมงเย็น || ''hok mong yen'' || 18:00 || 6:00 pm
|- style="background:#EEEEEE;"
| 1 at night|| หนึ่งทุ่ม || ''nueng thum'' || หนึ่งทุ่ม || ''nueng thum'' || 19:00 || 7:00 pm
|- style="background:#EEEEEE;"
| 2 at night || สองทุ่ม || ''song thum'' || สองทุ่ม || ''song thum'' || 20:00 || 8:00 pm
|- style="background:#EEEEEE;"
| 3 at night || สามทุ่ม || ''sam thum'' || สามทุ่ม || ''sam thum'' || 21:00 || 9:00 pm
|- style="background:#EEEEEE;"
| 4 at night || สี่ทุ่ม || ''si thum'' || สี่ทุ่ม || ''si thum'' || 22:00 || 10:00 pm
|- style="background:#EEEEEE;"
| 5 at night || ห้าทุ่ม || ''ha thum'' || ห้าทุ่ม ||''ha thum'' || 23:00 || 11:00 pm
|- style="background:#EEEEEE;"
| midnight || เที่ยงคืน,<br>หกทุ่ม,<br>สองยาม|| ''thiang khuen'',<br>''hok thum'',<br>''song yam'' || เที่ยงคืน,<br>หกทุ่ม|| ''thiang khuen'',<br>''hok thum'' || 24:00,<br>00:00 || 12:00 am
|}

:<small><sup>*</sup> The word ''chao (เช้า)'' is optional here since the numbers 7 to 11 are not used elsewhere</small>
:<small><sup>**</sup> Conversationally, ''si mong yen (สี่โมงเย็น)'' and ''ha mong yen (ห้าโมงเย็น)'' are also spoken if considered as evening</small>

== See also ==
* [[Time in Thailand]]
* [[Thai numerals]]

==References==
<references />

== Further reading ==
*{{citation|last=Royal Institute|title=พจนานุกรม ฉบับราชบัณฑิตยสถาน พ.ศ. ๒๕๔๒ (Royal Institute Dictionary, BE 2542)|place=Bangkok|publisher=Nanmee Books Publications|year=2003|ISBN=974-9588-04-5}}. {{th icon}}

{{Time measurement and standards}}

[[Category:Time measurement systems]]

{{Sourceattribution|Six-hour clock|1}}