{"id":2497,"date":"2016-09-18T22:50:25","date_gmt":"2016-09-18T22:50:25","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=2497"},"modified":"2024-08-22T17:18:17","modified_gmt":"2024-08-22T17:18:17","slug":"notacao-cientifica-ordem-de-grandeza-e-algarismos-significativos","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/introducao\/notacao-cientifica-ordem-de-grandeza-e-algarismos-significativos\/","title":{"rendered":"Nota\u00e7\u00e3o Cient\u00edfica, Ordem de Grandeza e Algarismos Significativos"},"content":{"rendered":"

Nota\u00e7\u00e3o Cient\u00edfica, Ordem de Grandeza e Algarismos Significativos<\/b><\/span><\/span><\/span><\/p>\n

Conceito de Nota\u00e7\u00e3o Cient\u00edfica<\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>Nota\u00e7\u00e3o Cient\u00edficas <\/b><\/span><\/span><\/span>serve para <\/b><\/span><\/span><\/span>facilitar<\/b><\/span><\/span><\/span> a <\/b><\/span><\/span><\/span>representa\u00e7\u00e3o de n\u00fameros muito pequenos <\/b><\/span><\/span><\/span>ou <\/b><\/span><\/span><\/span>muito<\/b><\/span><\/span><\/span> <\/b>grandes,<\/b><\/span><\/span><\/span> expressando-os <\/b><\/span><\/span><\/span>atrav\u00e9s de uma <\/b><\/span><\/span><\/span>forma mais f\u00e1cil de se trabalhar, diminuindo<\/b><\/span><\/span><\/span> seu <\/b><\/span><\/span><\/span>tamanho <\/b><\/span><\/span><\/span>atrav\u00e9s de uma <\/b><\/span><\/span><\/span>multiplica\u00e7\u00e3o por uma pot\u00eancia de 10 <\/b><\/span><\/span><\/span>(<\/b><\/span><\/span><\/span>nota\u00e7\u00e3o em forma exponencial<\/b><\/span><\/span><\/span>)<\/span><\/span><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Vantagens <\/b><\/span><\/span><\/span>em se <\/b><\/span><\/span><\/span>escrever<\/b><\/span><\/span><\/span> um <\/b><\/span><\/span><\/span>n\u00famero na nota\u00e7\u00e3o exponencial (nota\u00e7\u00e3o cient\u00edfica) <\/b><\/span><\/span><\/span>:<\/b><\/span><\/span><\/span><\/p>\n

\"\" Podem fazer com <\/b><\/span><\/span><\/span>que n\u00fameros muito grandes ou muito pequenos <\/b><\/span><\/span><\/span>possam ser <\/b><\/span><\/span><\/span>escritos de forma mais abreviada.<\/b><\/span><\/span><\/span><\/p>\n

Tornam os <\/b><\/span><\/span><\/span>c\u00e1lculos muito mais r\u00e1pidos e f\u00e1ceis.<\/b><\/span><\/span><\/span><\/p>\n

Exemplos num\u00e9ricos:<\/b><\/span><\/span><\/span><\/p>\n

\"\"\"\"<\/p>\n

\u00a0<\/span><\/p>\n

Quantidade de esp\u00e9cies<\/b><\/span><\/span><\/span> de <\/b><\/span><\/span><\/span>formigas catalogadas \"\"<\/b><\/span><\/span><\/span> mais de <\/b><\/span><\/span><\/span>10.000 \"\" <\/b><\/span><\/span><\/span>em<\/b><\/span><\/span><\/span> nota\u00e7\u00e3o cient\u00edfica 10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

Em \u00e1reas referentes a Qu\u00edmica e F\u00edsica costuma-se muito grandes ou muito pequenos, como por exemplo:<\/span><\/span><\/span><\/p>\n

\"\"\"\"<\/p>\n

A <\/b><\/span><\/span><\/span>massa <\/b><\/span><\/span><\/span>do\u00a0<\/b><\/span><\/span><\/span>pr\u00f3ton<\/b><\/span><\/span><\/span>\u00a0\u00e9 cerca de <\/b><\/span><\/span><\/span> <\/b>0,00000000000000000000000001673<\/b><\/span><\/span><\/span> <\/b>kg\u00a0\"\" <\/b><\/span><\/span><\/span>em nota\u00e7\u00e3o cient\u00edfica 1,673.10<\/b><\/span><\/span><\/span>-27 <\/b><\/span><\/span><\/sup><\/span>kg<\/b><\/span><\/span><\/span> <\/b>.<\/b><\/span><\/span><\/span> <\/b><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

A <\/b><\/span><\/span><\/span>dist\u00e2ncia m\u00e9dia <\/b><\/span><\/span><\/span>de <\/b><\/span><\/span><\/span>Netuno<\/b><\/span><\/span><\/span> ao <\/b><\/span><\/span><\/span>Sol<\/b><\/span><\/span><\/span> \u00e9 de <\/b><\/span><\/span><\/span>4.500.000.000 km \"\"<\/b><\/span><\/span><\/span> <\/b>em nota\u00e7\u00e3o cient\u00edfica 5,5.10<\/b><\/span><\/span><\/span>9<\/b><\/span><\/span><\/sup><\/span> km<\/b><\/span><\/span><\/span> <\/b>.<\/b><\/span><\/span><\/span> <\/b><\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

Representa\u00e7\u00e3o matem\u00e1tica de um n\u00famero sob a forma de nota\u00e7\u00e3o cient\u00edfica<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

Para que um <\/b><\/span><\/span><\/span>determinado n\u00famero N <\/b><\/span><\/span><\/span>seja <\/b><\/span><\/span><\/span>escrito sob forma de nota\u00e7\u00e3o cient\u00edfica <\/b><\/span><\/span><\/span>ele <\/b><\/span><\/span><\/span>deve obedecer <\/b><\/span><\/span><\/span>ao <\/b><\/span><\/span><\/span>seguinte modelo <\/b><\/span><\/span><\/span>que indica a <\/b><\/span><\/span><\/span>representa\u00e7\u00e3o de um n\u00famero atrav\u00e9s de uma multiplica\u00e7\u00e3o por uma pot\u00eancia de 10:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

 <\/p>\n

Como escrever n\u00fameros sob forma de Nota\u00e7\u00e3o Cient\u00edfica<\/span><\/span><\/span><\/p>\n

Exemplos:<\/b><\/span><\/span><\/span><\/p>\n

\"\" Voc\u00ea <\/b><\/span><\/span><\/span>coloca o n\u00famero<\/b><\/span><\/span><\/span>, por exemplo, <\/b><\/span><\/span><\/span>(19450) <\/b><\/span><\/span><\/span>e, em <\/b><\/span><\/span><\/span>seguida obt\u00e9m a mantissa <\/b><\/span><\/span><\/span>colocando a <\/b><\/span><\/span><\/span>v\u00edrgula depois do primeiro algarismo significativo <\/b><\/span><\/span><\/span>desse n\u00famero <\/b><\/span><\/span><\/span>(1,9450).<\/b><\/span><\/span><\/span> <\/b><\/p>\n

Se voc\u00ea <\/b><\/span><\/span><\/span>deslocar a v\u00edrgula 4 casas para a esquerda<\/b><\/span><\/span><\/span>, a<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>ordem de grandeza <\/b><\/span><\/span><\/span>b<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>ter\u00e1 o <\/b><\/span><\/span><\/span>mesmo n\u00famero <\/b><\/span><\/span><\/span>de <\/b><\/span><\/span><\/span>posi\u00e7\u00f5es deslocadas (4),<\/b><\/span><\/span><\/span> <\/b>ser\u00e1 positiva e a nota\u00e7\u00e3o cient\u00edfica do n\u00famero 19450 ser\u00e1 1,9450.10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

\"\" Voc\u00ea <\/b><\/span><\/span><\/span>coloca o n\u00famero, <\/b><\/span><\/span><\/span>por exemplo, <\/b><\/span><\/span><\/span>(- 0,00194) <\/b><\/span><\/span><\/span>e, em <\/b><\/span><\/span><\/span>seguida obt\u00e9m a mantissa <\/b><\/span><\/span><\/span>colocando a <\/b><\/span><\/span><\/span>v\u00edrgula depois do primeiro algarismo significativo desse n\u00famero (- 1,9450).<\/b><\/span><\/span><\/span> <\/b><\/p>\n

Como a <\/b><\/span><\/span><\/span>v\u00edrgula foi deslocada 3 casas para a direita, <\/b><\/span><\/span><\/span>a<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>ordem de grandeza <\/b><\/span><\/span><\/span>b<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>ter\u00e1 o <\/b><\/span><\/span><\/span>mesmo n\u00famero<\/b><\/span><\/span><\/span> <\/b>de posi\u00e7\u00f5es deslocadas (3), ser\u00e1 negativa e a nota\u00e7\u00e3o cient\u00edfica do n\u00famero – 0,0019450 ser\u00e1 – 1,9450.10<\/b><\/span><\/span><\/span>-3<\/b><\/span><\/span><\/sup><\/span> .<\/b><\/span><\/span><\/span><\/p>\n

\"\" A <\/b><\/span><\/span><\/span>ordem de grandeza do n\u00famero 1 escrito sob forma de nota\u00e7\u00e3o cientifica \u00e9 0 \"\" 1 = 1.10<\/b><\/span><\/span><\/span>0<\/b><\/span><\/span><\/sup><\/span>,<\/b><\/span><\/span><\/span> pois a <\/b><\/span><\/span><\/span>v\u00edrgula n\u00e3o sofru deslocamento.<\/b><\/span><\/span><\/span><\/p>\n

Lembre-se de que o <\/b><\/span><\/span><\/span>m\u00f3dulo\u00a0da mantissa <\/b><\/span><\/span><\/span>a<\/b><\/span><\/span><\/span> deve ser igual ou maior que\u00a0<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/span>\u00a0e menor que\u00a0<\/b><\/span><\/span><\/span>10<\/b><\/span><\/span><\/span>\u00a0e que <\/b><\/span><\/span><\/span>a\u00a0<\/b><\/span><\/span><\/span>ordem de grandeza<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>b<\/b><\/span><\/span><\/span> deve ser um n\u00famero inteiro.<\/b><\/span><\/span><\/span><\/p>\n

Assim, a <\/b><\/span><\/span><\/span>nota\u00e7\u00e3o cient\u00edfica do n\u00famero 24,2,10<\/b><\/span><\/span><\/span>-4<\/b><\/span><\/span><\/sup><\/span> n\u00e3o est\u00e1 escrito sob nota\u00e7\u00e3o cient\u00edfica correta<\/b><\/span><\/span><\/span>, pois a <\/b><\/span><\/span><\/span>mantissa \u00e9 maior que 10 <\/b><\/span><\/span><\/span>e o n\u00famero <\/b><\/span><\/span><\/span>3,3.10<\/b><\/span><\/span><\/span>7,5<\/b><\/span><\/span><\/sup><\/span> tamb\u00e9m n\u00e3o est\u00e1 escrito sob nota\u00e7\u00e3o cient\u00edfica correta,<\/b><\/span><\/span><\/span> pois a <\/b><\/span><\/span><\/span>ordem de grandeza\u00a0<\/b><\/span><\/span><\/span>7,5<\/b><\/span><\/span><\/span>\u00a0n\u00e3o \u00e9 um n\u00famero inteiro.<\/b><\/span><\/span><\/span><\/p>\n

Alguns n\u00fameros escritos sob forma de nota\u00e7\u00e3o cient\u00edfica:<\/span><\/span><\/span><\/span><\/p>\n

a) <\/b><\/span><\/span><\/span><\/span>620.000 = 6,2.10<\/b><\/span><\/span><\/span><\/span>5<\/b><\/span><\/span><\/span><\/sup><\/span> <\/b>b) <\/b><\/span><\/span><\/span>12.500 = 1,25,10<\/b><\/span><\/span><\/span>4<\/b><\/span><\/span><\/sup><\/span> <\/b>c) <\/b><\/span><\/span><\/span>– 600.000.00 0 = – 6,0.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span><\/p>\n

d) <\/b><\/span><\/span><\/span>5,55 = 5,55.10<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span> e)<\/b><\/span><\/span><\/span> – 60 = – 6,0.10<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sup><\/span><\/p>\n

Ordem de Grandeza<\/b><\/span><\/span><\/span><\/p>\n

Ordem de grandeza<\/b><\/span><\/span><\/span> <\/b>(OG) <\/b><\/span><\/span><\/span>\u00e9 uma <\/b><\/span><\/span><\/span>estimativa<\/b><\/span><\/span><\/span> do <\/b><\/span><\/span><\/span>valor de algo em termos de pot\u00eancia de 10<\/b><\/span><\/span><\/span>. <\/b><\/span><\/span><\/span><\/p>\n

Trata-se de uma <\/b><\/span><\/span><\/span>“no\u00e7\u00e3o” do valor daquela grandeza e, assim<\/b><\/span><\/span><\/span> \u00e9 a <\/b><\/span><\/span><\/span>pot\u00eancia de 10 mais pr\u00f3xima do valor que se deseja encontrar.<\/b><\/span><\/span><\/span><\/p>\n

Antes de determinar a ordem de grandeza (OG) de um n\u00famero X voc\u00ea precisa transform\u00e1-lo em nota\u00e7\u00e3o cient\u00edfica na forma X = a.10<\/b><\/span><\/span><\/span>n<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Como a <\/b><\/span><\/span><\/span>mantissa deve desaparecer voc\u00ea deve arredond\u00e1-la para a pot\u00eancia de 10 mais pr\u00f3xima. <\/b><\/span><\/span><\/span><\/p>\n

Assim, a <\/b><\/span><\/span><\/span>ordem de grandeza do n\u00famero 24 \u00e9 10<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sup><\/span> j\u00e1 que 24 est\u00e1 mais pr\u00f3ximo de 10<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sup><\/span> = 10 do que 10<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span> = 100.
\n<\/b><\/span><\/span><\/span>A <\/b><\/span><\/span><\/span>ordem de grandeza do n\u00famero 78 \u00e9 10<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span> j\u00e1 que 78 est\u00e1 mais pr\u00f3ximo de 10<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span> = 100 do que 10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span> = 1000.
\n<\/b><\/span><\/span><\/span>Ent\u00e3o, a <\/b><\/span><\/span><\/span>mantissa <\/b><\/span><\/span><\/span>(parte num\u00e9rica do n\u00famero que precede a pot\u00eancia de 10) <\/b><\/span><\/span><\/span> deve ser arredondada de acordo com a pot\u00eancia de 10 m\u00e9dia que deve estar est\u00e1 compreendida entre <\/b><\/span><\/span><\/span>o <\/b><\/span><\/span><\/span>ponto m\u00e9dio <\/b><\/span><\/span><\/span>do <\/b><\/span><\/span><\/span>intervalo [1 (10<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>) e 10 (10<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sup><\/span>)], ou seja, entre 10<\/b><\/span><\/span><\/span>(0 + 1)\/2<\/b><\/span><\/span><\/sup><\/span> = 10<\/b><\/span><\/span><\/span>1\/2<\/b><\/span><\/span><\/sup><\/span> = \"\" \"\" 3,1622.<\/b><\/span><\/span><\/span>\"\"<\/p>\n

Se a <\/b><\/span><\/span><\/span>mantissa<\/b><\/span><\/span><\/span> a<\/b><\/span><\/span><\/span> (parte num\u00e9rica do n\u00famero que precede a pot\u00eancia de 10) for menor que \"\" \"\" 3,1622, esse n\u00famero deve ser aproximado para 1\u00ba = 1, ficando 1.10<\/b><\/span><\/span><\/span>n<\/b><\/span><\/span><\/sup><\/span> com (n = 0,1,2,3,…).<\/b><\/span><\/span><\/span><\/p>\n

Se <\/b><\/span><\/span><\/span>a mantissa <\/b><\/span><\/span><\/span>(parte num\u00e9rica do n\u00famero que precede a pot\u00eancia de 10) <\/b><\/span><\/span><\/span>for maior que \"\" \"\" 3,1622, esse n\u00famero deve ser aproximado para 10<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sup><\/span> = 10, ficando 10.10<\/b><\/span><\/span><\/span>n<\/b><\/span><\/span><\/sup><\/span> = 10<\/b><\/span><\/span><\/span>(n ) <\/b><\/span><\/span><\/sup><\/span> com (n = 0,1,2,3,…).<\/b><\/span><\/span><\/span><\/p>\n

Exemplos<\/b><\/span><\/span><\/span><\/p>\n

01<\/b><\/span><\/span><\/span>– <\/b><\/span><\/span><\/span>\"\"<\/p>\n

O <\/b><\/span><\/span><\/span>n\u00famero de habitantes<\/b><\/span><\/span><\/span> no Brasil \u00e9 aproximadamente de <\/b><\/span><\/span><\/span>205.000.000. <\/b><\/span><\/span><\/span>A <\/b><\/span><\/span><\/span>OG <\/b><\/span><\/span><\/span>desse <\/b><\/span><\/span><\/span>n\u00famero <\/b><\/span><\/span><\/span>\u00e9<\/b><\/span><\/span><\/span><\/p>\n

2,05.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span> \"\"<\/b><\/span><\/span><\/span> 2,05 < 3,126 \"\" arredondado para 1 \"\" OG = 1.10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span> \"\" <\/b><\/span><\/span><\/span>OG = 10<\/b><\/span><\/span><\/span>8<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

02-<\/b><\/span><\/span><\/span> <\/b><\/p>\n

\"\"<\/p>\n

O <\/b><\/span><\/span><\/span>mol <\/b><\/span><\/span><\/span>\u00e9 uma <\/b><\/span><\/span><\/span>quantidade <\/b><\/span><\/span><\/span>bastante usada em <\/b><\/span><\/span><\/span>Qu\u00edmica e F\u00edsica <\/b><\/span><\/span><\/span>e vale, aproximadamente,<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>6,02 x10<\/b><\/span><\/span><\/span>23<\/b><\/span><\/span><\/sup><\/span>. <\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>OG <\/b><\/span><\/span><\/span>desse <\/b><\/span><\/span><\/span>n\u00famero <\/b><\/span><\/span><\/span>\u00e9 6,02 > 3,126 \"\" arredondado para 10 \"\" 10.10<\/b><\/span><\/span><\/span>23<\/b><\/span><\/span><\/sup><\/span> = 10<\/b><\/span><\/span><\/span>24<\/b><\/span><\/span><\/sup><\/span> \"\" <\/b><\/span><\/span><\/span>OG = 10<\/b><\/span><\/span><\/span>24<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

03-<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Qual \u00e9 a <\/b><\/span><\/span><\/span>ordem de grandeza da altura de uma pessoa adulta <\/b><\/span><\/span><\/span>normal? Resposta: Est\u00e1 <\/b><\/span><\/span><\/span>compreendida entre 1m e 2m <\/b><\/span><\/span><\/span>e ter\u00e1 <\/b><\/span><\/span><\/span>OG = (1 ou 2).10<\/b><\/span><\/span><\/span>0<\/b><\/span><\/span><\/sup><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

04-<\/b><\/span><\/span><\/span> <\/b><\/p>\n

\"\"<\/p>\n

Ordem de grandeza da <\/b><\/span><\/span><\/span>quantidade de \u00e1gua nos oceanos da Terra \"\"<\/b><\/span><\/span><\/span> <\/b>1.350.000. 000.000.000.000.000 L \"\" <\/b><\/span><\/span><\/span>1,35.10<\/b><\/span><\/span><\/span>21<\/b><\/span><\/span><\/sup><\/span> \"\"<\/b><\/span><\/span><\/span> 1.10<\/b><\/span><\/span><\/span>21<\/b><\/span><\/span><\/sup><\/span> \"\" OG = 10<\/b><\/span><\/span><\/span>21<\/b><\/span><\/span><\/sup><\/span> L.<\/b><\/span><\/span><\/span><\/p>\n

05- <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Ordem de grandeza da <\/b><\/span><\/span><\/span>massa de um \u00e1tomo \"\"0,000.000.000.000.000.000.000.000.1992 kg \"\" 1,992.10<\/b><\/span><\/span><\/span>-27 <\/b><\/span><\/span><\/sup><\/span>kg \"\" OG = 10<\/b><\/span><\/span><\/span>-27<\/b><\/span><\/span><\/sup><\/span> kg.<\/b><\/span><\/span><\/span><\/p>\n

Algarismos significativos<\/b><\/span><\/span><\/span><\/p>\n

Algarismos significativos e incerteza<\/b><\/span><\/span><\/span><\/p>\n

Excetuando-se quando <\/b><\/span><\/span><\/span>todos os n\u00fameros envolvidos s\u00e3o inteiros,<\/b><\/span><\/span><\/span> como por exemplo, o <\/b><\/span><\/span><\/span>n\u00famero de pessoas numa sala de<\/b><\/span><\/span><\/span> <\/b>aula (45), <\/b><\/span><\/span><\/span>\u00e9 <\/b><\/span><\/span><\/span>imposs\u00edvel determinar o valor exato <\/b><\/span><\/span><\/span>de determinada quantidade, como por exemplo, o <\/b><\/span><\/span><\/span>n\u00famero de pessoas gordas e magras, greandes e pequenas que enchem totalmente uma perua. <\/b><\/span><\/span><\/span>\"\"<\/p>\n

Ent\u00e3o, \u00e9 <\/b><\/span><\/span><\/span>importante indicar a margem de erro numa medi\u00e7\u00e3o <\/b><\/span><\/span><\/span>indicando os <\/b><\/span><\/span><\/span>algarismos significativos,<\/b><\/span><\/span><\/span> sendo estes os<\/b><\/span><\/span><\/span> d\u00edgitos com significado numa quantidade ou medi\u00e7\u00e3o<\/b><\/span><\/span><\/span>. <\/span><\/span><\/span><\/p>\n

Qualquer <\/b><\/span><\/span><\/span>medida <\/b><\/span><\/span><\/span>que voc\u00ea fizer <\/b><\/span><\/span><\/span>experimentalmente fornece informa\u00e7\u00e3o limitada <\/b><\/span><\/span><\/span>e nenhum processo de medi\u00e7\u00e3o \u00e9 <\/b><\/span><\/span><\/span>totalmente confi\u00e1vel.<\/b><\/span><\/span><\/span><\/p>\n

Assim, ao <\/b><\/span><\/span><\/span>efetuar qualquer medida \u00e9 necess\u00e1rio deixar indicado o ponto at\u00e9 o qual se pode confiar no resultado obtido. <\/b><\/span><\/span><\/span><\/p>\n

Veja, no <\/b><\/span><\/span><\/span>exemplo a seguir como voc\u00ea determinar as incertezas de uma medi\u00e7\u00e3o, <\/b><\/span><\/span><\/span>medindo o <\/b><\/span><\/span><\/span>comprimento de uma caneta usando uma r\u00e9gua cuja menor divis\u00e3o de escala \u00e9 o mil\u00edmetro. <\/b><\/span><\/span><\/span>\"\"<\/p>\n

Observe <\/b><\/span><\/span><\/span>na figura <\/b><\/span><\/span><\/span>que o <\/b><\/span><\/span><\/span>comprimento da caneta <\/b><\/span><\/span><\/span>est\u00e1 <\/b><\/span><\/span><\/span>aproximadamente entre 14,6 cm e 14,7 cm<\/b><\/span><\/span><\/span><\/p>\n

Vamos supor que <\/b><\/span><\/span><\/span>voc\u00ea afirme essa caneta possua possua 14,63 cm.<\/b><\/span><\/span><\/span><\/p>\n

Assim,voc\u00ea pode afirmar, <\/b><\/span><\/span><\/span>com certeza, que o comprimento da caneta est\u00e1 entre 14,6 cm e 14,7 cm <\/b><\/span><\/span><\/span>e que, <\/b><\/span><\/span><\/span>na medida 14,63 cm o algarismo 3 \u00e9 incerto, que foi estimado por voc\u00ea.<\/b><\/span><\/span><\/span>
\n<\/b><\/span><\/span><\/span>Algarismos significativos s\u00e3o todos os que expressam o valor medido at\u00e9 o primeiro incerto,<\/b><\/span><\/span><\/span> <\/b>inclusive este \u00faltimo. <\/b><\/span><\/span><\/span>Ent\u00e3o o <\/b><\/span><\/span><\/span>n\u00famero de nosso exemplo (14,63) possui 4 algarismos significativos.<\/b><\/span><\/span><\/span><\/p>\n

Regras para algarismos significativos<\/span><\/span><\/span><\/p>\n

Zeros consecutivos \u00e0 esquerda n\u00e3o s\u00e3o algarismos significativos significativos. Exemplos<\/b><\/span><\/span><\/span>:<\/span><\/span><\/span>
\n\"\"<\/span><\/span><\/span> 0, 0000012 <\/b><\/span><\/span><\/span>(tem 2 algarismos significativos).<\/b><\/span><\/span><\/span>
\n<\/b><\/span><\/span><\/span>
\n\"\"<\/span><\/span><\/span> <\/b>0,0004567 <\/b><\/span><\/span><\/span>(tem 4 algarismos significativos).<\/b><\/span><\/span><\/span><\/p>\n

\"\" 00,000005<\/b><\/span><\/span><\/span> (tem 1 algarismo significativo).<\/b><\/span><\/span><\/span><\/p>\n


\n\"\"<\/span><\/span><\/span> Zeros \u00e0 direita s\u00e3o considerados e n\u00e3o podem ser desprezados no caso de medi\u00e7\u00f5es<\/b><\/span><\/span><\/span>. <\/span><\/span><\/span>Exemplos:<\/b><\/span><\/span><\/span>
\n\"\"<\/b><\/span><\/span><\/span> <\/b>3,24000<\/b><\/span><\/span><\/span> (tem 6 algarismos significativos).<\/b><\/span><\/span><\/span>
\n<\/span><\/span><\/span><\/p>\n

\"\" 0,0000500<\/b><\/span><\/span><\/span> (tem tr\u00eas algarismos significativos).<\/b><\/span><\/span><\/span><\/p>\n

Se a <\/b><\/span><\/span><\/span>incerteza<\/b><\/span><\/span><\/span> <\/b>n\u00e3o for especificada,<\/b><\/span><\/span><\/span> \u00e9 usual que ela seja <\/b><\/span><\/span><\/span>subentendida como <\/b><\/span><\/span><\/span>uma unidade<\/b><\/span><\/span><\/span> <\/b>decimal<\/b><\/span><\/span><\/span> da casa correspondente ao \u00faltimo algarismo. Exemplo:<\/b><\/span><\/span><\/span>
\n\"\"<\/b><\/span><\/span><\/span> 47,07 m equivale a 47,07 \u00b1 0,01 m <\/b><\/span><\/span><\/span>e, <\/b><\/span><\/span><\/span>s<\/b><\/span><\/span><\/span>e a <\/b><\/span><\/span><\/span>incerteza \u00e9 conhecida, ela deve ser especificada como, <\/b><\/span><\/span><\/span>por exemplo, <\/b><\/span><\/span><\/span>52,35 \u00b1 0,02 km. <\/b><\/span><\/span><\/span>
\n<\/b><\/span><\/span><\/span>Observe que o<\/b><\/span><\/span><\/span>s <\/b><\/span><\/span><\/span>resultados de <\/b><\/span><\/span><\/span>todas as medidas <\/b><\/span><\/span><\/span>devem sempre ser expressas com a mesma quantidade de casas decimais que suas respectivas incertezas. <\/b><\/span><\/span><\/span>Assim, voc\u00ea <\/b><\/span><\/span><\/span>n\u00e3o pode escrever 35,7 <\/b><\/span><\/span><\/span>\u00b1 0,01.<\/b><\/span><\/span><\/span><\/p>\n

\"\" Quando um <\/b><\/span><\/span><\/span>n\u00famero \u00e9 expresso em termos de ordem de grandeza,<\/b><\/span><\/span><\/span> a <\/b><\/span><\/span><\/span>pot\u00eancia de dez<\/b><\/span><\/span><\/span> <\/b>deve <\/b><\/span><\/span><\/span>ser desprezada no c\u00e1lculo dos n\u00fameros de algarismos significativos. <\/b><\/span><\/span><\/span><\/p>\n

Exemplo \"\"<\/b><\/span><\/span> os <\/b><\/span><\/span><\/span>dois membros da igualdade 3675,8 = 3,6758.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span> <\/b>possuem <\/b><\/span><\/span><\/span>5 algarismos significativos. <\/b><\/span><\/span><\/span>A <\/b><\/span><\/span><\/span>pot\u00eancia de dez n\u00e3o influi,<\/b><\/span><\/span><\/span> <\/b>ela <\/b><\/span><\/span><\/span>apenas desloca a v\u00edrgula, <\/b><\/span><\/span><\/span>o que <\/b><\/span><\/span><\/span>n\u00e3o afeta a quantidade de algarismos significativos.<\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>posi\u00e7\u00e3o da v\u00edrgula n\u00e3o influi no n\u00famero de algarismos significativos.<\/b><\/span><\/span><\/span><\/p>\n

Assim, o <\/b><\/span><\/span><\/span>comprimento de 0,00450 m <\/b><\/span><\/span><\/span>possui <\/b><\/span><\/span><\/span>tr\u00eas algarismos significativos <\/b><\/span><\/span><\/span>e pode ter <\/b><\/span><\/span><\/span>a posi\u00e7\u00e3o da v\u00edrgula alterado de v\u00e1rias formas usando uma pot\u00eancia de dez adequada, e sem alterar o seu n\u00famero de algarismos significativos.<\/b><\/span><\/span><\/span><\/p>\n

0,00450 m = 4,50 .10<\/b><\/span><\/span><\/span>-3 <\/b><\/span><\/span><\/sup><\/span>m = 0,0450 dm = 0,450 cm = 4,50 mm<\/b><\/span><\/span><\/span><\/p>\n

Observe que o <\/b><\/span><\/span><\/span>n\u00famero de algarismos significativos \u00e9 sempre tr\u00eas,<\/b><\/span><\/span><\/span> <\/b>independentemente<\/b><\/span><\/span><\/span> da forma que o <\/b><\/span><\/span><\/span>n\u00famero foi escrito e da posi\u00e7\u00e3o de sua v\u00edrgula.<\/b><\/span><\/span><\/span> <\/b><\/p>\n

Observe tamb\u00e9m que o <\/b><\/span><\/span><\/span>valor da medida \u00e9 sempre a mesma, <\/b><\/span><\/span><\/span>j\u00e1 que: <\/b><\/span><\/span><\/span>0,00450 m = 0,0450 dm = 0,450 cm = 4,50 mm<\/b><\/span><\/span><\/span><\/p>\n

O que voc\u00ea deve saber, informa\u00e7\u00f5es e dicas<\/b><\/span><\/span><\/span><\/p>\n

\"\" Conhecer o <\/b><\/span><\/span><\/span>conceito <\/b><\/span><\/span><\/span> de Nota\u00e7\u00e3o Cient\u00edfica<\/b><\/span><\/span><\/span><\/p>\n

\"\" Saber <\/b><\/span><\/span>escrever n\u00fameros <\/b><\/span><\/span>sob forma de <\/b><\/span><\/span>nota\u00e7\u00e3o cient\u00edfica e, <\/b><\/span><\/span>posteriormente sob forma<\/b><\/span><\/span> de ordem de grandeza.<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\" Conhecer os <\/b><\/span><\/span><\/span>conceitos de algarismos significativos.<\/b><\/span><\/span><\/span><\/p>\n

\"\" Saber as <\/b><\/span><\/span><\/span>regras para se escrever algarismos significativos<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

Confira os exerc\u00edcios propostos<\/span><\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"

Nota\u00e7\u00e3o Cient\u00edfica, Ordem de Grandeza e Algarismos Significativos Conceito de Nota\u00e7\u00e3o Cient\u00edfica A Nota\u00e7\u00e3o Cient\u00edficas serve para facilitar a representa\u00e7\u00e3o de n\u00fameros muito pequenos ou muito grandes, expressando-os atrav\u00e9s de uma forma mais f\u00e1cil de se trabalhar, diminuindo seu tamanho atrav\u00e9s de uma multiplica\u00e7\u00e3o por uma pot\u00eancia de 10 (nota\u00e7\u00e3o em forma exponencial). Vantagens em se escrever um n\u00famero na<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":129,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-2497","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2497","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/comments?post=2497"}],"version-history":[{"count":2,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2497\/revisions"}],"predecessor-version":[{"id":2505,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2497\/revisions\/2505"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/129"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=2497"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}