Trong nhi\u1ec1u th\u00e0nh ph\u1ed1 l\u1edbn \u0111\u1ec1u c\u00f3 nh\u1eefng chi\u1ebfc \u0111\u1ed3ng h\u1ed3 b\u00e1o gi\u1edd \u0111\u1ed3 s\u1ed9 v\u01b0\u01a1n cao l\u00ean, ti\u1ebfng chu\u00f4ng du d\u01b0\u01a1ng b\u00e1o th\u1eddi gian chu\u1ea9n x\u00e1c cho m\u1ecdi ng\u01b0\u1eddi \u1edf xung quanh.<\/p>\n\n\n\n
N\u1ebfu b\u1ea1n l\u00e0 ng\u01b0\u1eddi hay \u0111\u1ec3 \u00fd th\u00ec s\u1ebd c\u1ea3m th\u1ea5y: ban \u0111\u00eam v\u00e0 s\u00e1ng s\u1edbm, ti\u1ebfng chu\u00f4ng nghe r\u1ea5t r\u00f5; c\u00f2n ban ng\u00e0y, ti\u1ebfng chu\u00f4ng ch\u1ec9 thoang tho\u1ea3ng, th\u1eadm ch\u00ed c\u00f3 l\u00fac kh\u00f4ng nghe th\u1ea5y g\u00ec c\u1ea3. C\u00f3 th\u1ec3 c\u00f3 ng\u01b0\u1eddi s\u1ebd n\u00f3i: \u0111\u00f3 l\u00e0 v\u00ec m\u00f4i tr\u01b0\u1eddng ban \u0111\u00eam v\u00e0 s\u00e1ng s\u1edbm y\u00ean t\u0129nh, c\u00f2n ban ng\u00e0y th\u00ec \u00e2m thanh h\u1ed7n t\u1ea1p, \u1ed3n \u00e0o.<\/p>\n\n\n\n
C\u00e1ch gi\u1ea3i th\u00edch nh\u01b0 v\u1eady ch\u1ec9 \u0111\u00fang m\u1ed9t ph\u1ea7n, kh\u00f4ng \u0111\u01b0\u1ee3c tr\u1ecdn v\u1eb9n. C\u00f2n m\u1ed9t nguy\u00ean nh\u00e2n quan tr\u1ecdng kh\u00e1c l\u00e0 \u00e2m thanh c\u00f3 kh\u1ea3 n\u0103ng “r\u1ebd ngo\u1eb7t”.<\/p>\n\n\n\n
\u00c2m thanh d\u1ef1a v\u00e0o kh\u00f4ng kh\u00ed \u0111\u1ec3 lan truy\u1ec1n. Trong kh\u00f4ng kh\u00ed nhi\u1ec7t \u0111\u1ed9 \u0111\u1ed3ng \u0111\u1ec1u, n\u00f3 truy\u1ec1n th\u1eb3ng t\u1eafp v\u1ec1 ph\u00eda tr\u01b0\u1edbc; m\u1ed9t khi g\u1eb7p ph\u1ea3i nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng kh\u00ed ch\u1ed7 cao ch\u1ed7 th\u1ea5p, n\u00f3 c\u1ed1 s\u1ee9c ch\u1ecdn n\u01a1i c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p m\u00e0 truy\u1ec1n. Th\u1ebf l\u00e0 \u00e2m thanh li\u1ec1n “r\u1ebd ngo\u1eb7t” ngay.<\/p>\n\n\n\n
Ban ng\u00e0y, M\u1eb7t Tr\u1eddi hun n\u00f3ng m\u1eb7t \u0111\u1ea5t l\u00ean, kh\u00f4ng kh\u00ed \u1edf g\u1ea7n m\u1eb7t \u0111\u1ea5t c\u00f3 nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n \u1edf tr\u00ean kh\u00f4ng r\u1ea5t nhi\u1ec1u. Ti\u1ebfng chu\u00f4ng sau khi ph\u00e1t ra, truy\u1ec1n \u0111i ch\u01b0a \u0111\u01b0\u1ee3c bao xa li\u1ec1n ngo\u1eb7t l\u00ean tr\u00ean cao, n\u01a1i c\u00f3 nhi\u1ec7t \u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed1i th\u1ea5p. V\u00ec v\u1eady, tr\u00ean m\u1eb7t \u0111\u1ea5t, \u1edf ngo\u00e0i m\u1ed9t kho\u1ea3ng c\u00e1ch nh\u1ea5t \u0111\u1ecbnh, ti\u1ebfng chu\u00f4ng nghe kh\u00f4ng \u0111\u01b0\u1ee3c r\u00f5, xa ch\u00fat n\u1eefa th\u00ec kh\u00f4ng nghe th\u1ea5y ti\u1ebfng chu\u00f4ng. Ban \u0111\u00eam v\u00e0 s\u00e1ng s\u1edbm, t\u00ecnh tr\u1ea1ng n\u00f3ng l\u1ea1nh c\u1ee7a kh\u00f4ng kh\u00ed x\u1ea3y ra ng\u01b0\u1ee3c l\u1ea1i: nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng kh\u00ed g\u1ea7n m\u1eb7t \u0111\u1ea5t th\u1ea5p h\u01a1n \u1edf tr\u00ean cao. Ti\u1ebfng chu\u00f4ng sau khi ph\u00e1t ra li\u1ec1n thu\u1eadn theo m\u1eb7t \u0111\u1ea5t, n\u01a1i c\u00f3 nhi\u1ec7t \u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed1i th\u1ea5p m\u00e0 truy\u1ec1n. V\u00ec th\u1ebf, ng\u01b0\u1eddi \u1edf n\u01a1i r\u1ea5t xa c\u0169ng c\u00f3 th\u1ec3 nghe r\u00f5 \u0111\u01b0\u1ee3c ti\u1ebfng chu\u00f4ng. Xem ra, c\u00e2u th\u01a1 “b\u00e1n d\u1ea1 chung thanh \u0111\u00e1o kh\u00e1ch thuy\u1ec1n” (n\u1eeda \u0111\u00eam nghe ti\u1ebfng chu\u00f4ng v\u1eb3ng \u0111\u1ebfn thuy\u1ec1n kh\u00e1ch) qu\u1ea3 c\u0169ng l\u00e0 c\u00f3 c\u0103n c\u1ee9 khoa h\u1ecdc \u0111\u1ea5y ch\u1ee9!<\/p>\n\n\n\n
Lo\u1ea1i t\u00ednh ch\u1ea5t n\u00e0y c\u1ee7a \u00e2m thanh c\u00f3 th\u1ec3 t\u1ea1o n\u00ean m\u1ed9t s\u1ed1 hi\u1ec7n t\u01b0\u1ee3ng l\u00ed th\u00fa. Trong sa m\u1ea1c n\u00f3ng b\u1ee9c, nhi\u1ec7t \u0111\u1ed9 g\u1ea7n m\u1eb7t \u0111\u1ea5t t\u01b0\u01a1ng \u0111\u1ed1i cao. N\u1ebfu \u1edf ngo\u00e0i 50 ~ 60 m c\u00f3 ng\u01b0\u1eddi h\u00fa g\u1ecdi to th\u00ec ch\u1ec9 c\u00f3 th\u1ec3 th\u1ea5y mi\u1ec7ng ng\u01b0\u1eddi \u1ea5y m\u1ea5p m\u00e1y c\u1eed \u0111\u1ed9ng, m\u00e0 kh\u00f4ng nghe \u0111\u01b0\u1ee3c \u00e2m thanh. \u0110\u00f3 l\u00e0 v\u00ec sau khi ti\u1ebfng h\u00fa ph\u00e1t ra, \u00e2m thanh li\u1ec1n ngo\u1eb7t r\u1ea5t nhanh l\u00ean tr\u00ean cao \u0111i m\u1ea5t. Ng\u01b0\u1ee3c l\u1ea1i, \u1edf v\u00f9ng b\u0103ng tuy\u1ebft m\u00eanh m\u00f4ng, nhi\u1ec7t \u0111\u1ed9 g\u1ea7n m\u1eb7t \u0111\u1ea5t th\u1ea5p h\u01a1n \u1edf tr\u00ean kh\u00f4ng, \u00e2m thanh ho\u00e0n to\u00e0n lan truy\u1ec1n theo m\u1eb7t \u0111\u1ea5t; v\u00ec v\u1eady, khi c\u00f3 ng\u01b0\u1eddi h\u00fa g\u1ecdi ta, \u00e2m thanh c\u00f3 th\u1ec3 truy\u1ec1n \u0111i r\u1ea5t xa, th\u1eadm ch\u00ed ngo\u00e0i 1000 ~ 2000 m c\u0169ng c\u00f3 th\u1ec3 nghe \u0111\u01b0\u1ee3c. C\u00f3 khi do nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng kh\u00ed g\u1ea7n m\u1eb7t \u0111\u1ea5t ch\u1ee3t cao, ch\u1ee3t th\u1ea5p, \u00e2m thanh c\u0169ng theo \u0111\u00f3 m\u00e0 ngo\u1eb7t l\u00ean ngo\u1eb7t xu\u1ed1ng, th\u01b0\u1eddng hay t\u1ea1o th\u00e0nh m\u1ed9t s\u1ed1 khu v\u1ef1c t\u01b0\u01a1ng \u0111\u1ed1i g\u1ea7n kh\u00f4ng nghe \u0111\u01b0\u1ee3c \u00e2m thanh, \u1edf n\u01a1i xa h\u01a1n th\u00ec l\u1ea1i c\u00f3 th\u1ec3 nghe \u0111\u01b0\u1ee3c. Th\u00e1ng 6 n\u0103m 1815, trong chi\u1ebfn d\u1ecbch Waterlo n\u1ed5i ti\u1ebfng, sau khi cu\u1ed9c chi\u1ebfn b\u00f9ng n\u1ed5 qu\u00e2n \u0111o\u00e0n “C\u1edd ru xi” \u0111\u00f3ng qu\u00e2n kh\u00f4ng xa chi\u1ebfn tr\u01b0\u1eddng, c\u00e1ch \u0111\u1ea5y 25 km, m\u00e0 kh\u00f4ng m\u1ed9t ai nghe th\u1ea5y ti\u1ebfng s\u00fang l\u1edbn, v\u00ec v\u1eady kh\u00f4ng th\u1ec3 k\u1ecbp th\u1eddi ch\u1ea1y \u0111\u1ebfn chi vi\u1ec7n cho Napoleon theo k\u1ebf ho\u1ea1ch t\u00e1c chi\u1ebfn. V\u1eady m\u00e0 \u1edf m\u1ed9t n\u01a1i xa h\u01a1n, ti\u1ebfng \u0111\u1ea1i b\u00e1c \u00f9ng o\u00e0ng l\u1ea1i nghe r\u00f5 m\u1ed3n m\u1ed9t. T\u00ednh ch\u1ea5t lan truy\u1ec1n c\u1ee7a \u00e2m thanh l\u1ea1i \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn chuy\u1ec7n th\u1eafng b\u1ea1i c\u1ee7a m\u1ed9t chi\u1ebfn d\u1ecbch nh\u01b0 th\u1ebf \u0111\u1ea5y!<\/p>\n\n\n\n
T\u1eeb kh\u00f3a: \u00c2m thanh truy\u1ec1n lan.<\/p>\n\n\n\n
<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
Trong nhi\u1ec1u th\u00e0nh ph\u1ed1 l\u1edbn \u0111\u1ec1u c\u00f3 nh\u1eefng chi\u1ebfc \u0111\u1ed3ng h\u1ed3 b\u00e1o gi\u1edd \u0111\u1ed3 s\u1ed9 v\u01b0\u01a1n cao l\u00ean, ti\u1ebfng chu\u00f4ng du d\u01b0\u01a1ng b\u00e1o th\u1eddi gian chu\u1ea9n x\u00e1c cho m\u1ecdi ng\u01b0\u1eddi \u1edf xung quanh. N\u1ebfu b\u1ea1n l\u00e0 ng\u01b0\u1eddi hay \u0111\u1ec3 \u00fd th\u00ec s\u1ebd c\u1ea3m th\u1ea5y: ban \u0111\u00eam v\u00e0 s\u00e1ng s\u1edbm, ti\u1ebfng chu\u00f4ng nghe r\u1ea5t r\u00f5; c\u00f2n […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[15,7],"tags":[],"class_list":["post-5598","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-vat-ly"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5598","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=5598"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5598\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=5598"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=5598"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=5598"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}