{"id":80,"date":"2020-12-14T20:03:24","date_gmt":"2020-12-15T01:03:24","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/?post_type=chapter&#038;p=80"},"modified":"2021-01-03T18:26:15","modified_gmt":"2021-01-03T23:26:15","slug":"si-systeme-international-or-the-metric-system","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/chapter\/si-systeme-international-or-the-metric-system\/","title":{"raw":"SI Syst\u00e8me International or the Metric System","rendered":"SI Syst\u00e8me International or the Metric System"},"content":{"raw":"SI is the abbreviation of the French \"Syst\u00e8me International d'Unit\u00e9s\".\r\n\r\nBIPM is the Bureau International des Poids et Mesures,\u00a0 The official website for this \"intergovernmental organization through which Member States act together on matters related to measurement science and measurement standards\" can be accessed at\r\n\r\n<a href=\"https:\/\/www.bipm.org\/en\/measurement-units\/\">https:\/\/www.bipm.org\/en\/measurement-units\/<\/a>\r\n\r\nSince most countries in the world use this officially, including Canada, you are expected to be familiar with its use.\r\n<h1>Prefixes<\/h1>\r\nWhen a number is very large or very small, the units are modified using a prefix.\r\n\r\n1 000 000 000 000 = 10<sup>12<\/sup> = tera = T\r\n\r\n1 000 000 000 = 10<sup>9<\/sup> = giga= G\r\n\r\n1 000 000 = 10<sup>6<\/sup> = mega = M\r\n\r\n1 000 = 10<sup>3<\/sup> = kilo = k\r\n\r\n&nbsp;\r\n\r\n0.001 = 10<sup>-3<\/sup> = milli = m\r\n\r\n0.000 001 = 10<sup>-6<\/sup> = micro = \u03bc\u00a0 (pronounced \"mu\")\r\n\r\n0.000 000 001 = 10<sup>-9<\/sup> = nano = n\r\n\r\n0.000 000 000 001 = 10<sup>-12<\/sup> = pico = p\r\n<h1>Rules for Use of the metric prefixes<\/h1>\r\nThere are a few rules for the proper use of SI units\r\n<ul>\r\n \t<li>Quantities that are defined by several units are separated by a dot \"\u00b7\" to avoid confusion with the prefix notations.\u00a0 For example a newton is correctly written as kg \u00b7 m \/s<sup>2<\/sup> or kg \u00b7 m \u00b7 s<sup>-2<\/sup> .\u00a0 \u00a0Metre-second is written as m \u00b7 s as opposed to millisecond which would be written as ms.<\/li>\r\n \t<li>When the unit is raised to an exponent, such as m<sup>2<\/sup> or N<sup>2\u00a0<\/sup>, the prefix refers to both the unit and its prefix.\u00a0 This is very confusing.\u00a0 \u00a0For volume, a cubic millimetre is written as mm<sup>3<\/sup>, it means (mm)<sup>3<\/sup> = mm \u00b7 mm \u00b7 mm = 10<sup>-9<\/sup>\u00a0m<sup>3<\/sup>.<\/li>\r\n \t<li>The kilogram is an exception to this general rule.\u00a0 You want to keep kg as much as possible.\u00a0 \u00a0In general, you want to avoid having the prefix in the denominator.\u00a0 Do not write seconds per mm or s\/mm but write ks\/m.\u00a0 Metres per milligram or m\/mg should be written as Mm\/kg as kg is a base unit.<\/li>\r\n<\/ul>\r\n&nbsp;\r\n\r\n&nbsp;","rendered":"<p>SI is the abbreviation of the French &#8220;Syst\u00e8me International d&#8217;Unit\u00e9s&#8221;.<\/p>\n<p>BIPM is the Bureau International des Poids et Mesures,\u00a0 The official website for this &#8220;intergovernmental organization through which Member States act together on matters related to measurement science and measurement standards&#8221; can be accessed at<\/p>\n<p><a href=\"https:\/\/www.bipm.org\/en\/measurement-units\/\">https:\/\/www.bipm.org\/en\/measurement-units\/<\/a><\/p>\n<p>Since most countries in the world use this officially, including Canada, you are expected to be familiar with its use.<\/p>\n<h1>Prefixes<\/h1>\n<p>When a number is very large or very small, the units are modified using a prefix.<\/p>\n<p>1 000 000 000 000 = 10<sup>12<\/sup> = tera = T<\/p>\n<p>1 000 000 000 = 10<sup>9<\/sup> = giga= G<\/p>\n<p>1 000 000 = 10<sup>6<\/sup> = mega = M<\/p>\n<p>1 000 = 10<sup>3<\/sup> = kilo = k<\/p>\n<p>&nbsp;<\/p>\n<p>0.001 = 10<sup>-3<\/sup> = milli = m<\/p>\n<p>0.000 001 = 10<sup>-6<\/sup> = micro = \u03bc\u00a0 (pronounced &#8220;mu&#8221;)<\/p>\n<p>0.000 000 001 = 10<sup>-9<\/sup> = nano = n<\/p>\n<p>0.000 000 000 001 = 10<sup>-12<\/sup> = pico = p<\/p>\n<h1>Rules for Use of the metric prefixes<\/h1>\n<p>There are a few rules for the proper use of SI units<\/p>\n<ul>\n<li>Quantities that are defined by several units are separated by a dot &#8220;\u00b7&#8221; to avoid confusion with the prefix notations.\u00a0 For example a newton is correctly written as kg \u00b7 m \/s<sup>2<\/sup> or kg \u00b7 m \u00b7 s<sup>-2<\/sup> .\u00a0 \u00a0Metre-second is written as m \u00b7 s as opposed to millisecond which would be written as ms.<\/li>\n<li>When the unit is raised to an exponent, such as m<sup>2<\/sup> or N<sup>2\u00a0<\/sup>, the prefix refers to both the unit and its prefix.\u00a0 This is very confusing.\u00a0 \u00a0For volume, a cubic millimetre is written as mm<sup>3<\/sup>, it means (mm)<sup>3<\/sup> = mm \u00b7 mm \u00b7 mm = 10<sup>-9<\/sup>\u00a0m<sup>3<\/sup>.<\/li>\n<li>The kilogram is an exception to this general rule.\u00a0 You want to keep kg as much as possible.\u00a0 \u00a0In general, you want to avoid having the prefix in the denominator.\u00a0 Do not write seconds per mm or s\/mm but write ks\/m.\u00a0 Metres per milligram or m\/mg should be written as Mm\/kg as kg is a base unit.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"author":9,"menu_order":5,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-80","chapter","type-chapter","status-publish","hentry"],"part":161,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/pressbooks\/v2\/chapters\/80","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/wp\/v2\/users\/9"}],"version-history":[{"count":4,"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/pressbooks\/v2\/chapters\/80\/revisions"}],"predecessor-version":[{"id":209,"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/pressbooks\/v2\/chapters\/80\/revisions\/209"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/pressbooks\/v2\/parts\/161"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/pressbooks\/v2\/chapters\/80\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/wp\/v2\/media?parent=80"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/pressbooks\/v2\/chapter-type?post=80"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/wp\/v2\/contributor?post=80"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/bcengrphys3\/wp-json\/wp\/v2\/license?post=80"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}