chuy\u00ean gia<\/a> qua nhi\u1ec1u l\u1ea7n ki\u1ec3m tra \u0111\u1ec1u k\u1ebft lu\u1eadn: \u0111\u00f3 l\u00e0 do m\u1ed7i c\u0103n ph\u00f2ng trong ng\u00f4i nh\u00e0 \u0111\u00f3 t\u00ednh n\u0103ng h\u1ea5p thu \u00e2m qu\u00e1 t\u1ed1t. V\u1ec1 sau c\u00f3 m\u1ed9t ki\u1ebfn tr\u00fac s\u01b0 \u0111\u00e3 \u0111\u01b0a ra \u00fd ki\u1ebfn: trong m\u1ed7i ph\u00f2ng l\u1eafp th\u00eam m\u1ed9t m\u00e1y rung c\u1ee1 nh\u1ecf, ph\u00e1t ra nh\u1eefng \u00e2m thanh nh\u1ecf nh\u1eb9 v\u00e0 kh\u00f4ng \u0111\u1ec1u. Sau m\u1ea5y ng\u00e0y th\u00ec d\u00e2n c\u01b0 s\u1ed1ng trong ng\u00f4i nh\u00e0 \u0111\u00f3 s\u1ee9c kh\u1ecfe tr\u1edf l\u1ea1i b\u00ecnh th\u01b0\u1eddng.<\/p>\n\n\n\nC\u00e1c nh\u00e0 t\u00e2m l\u00ed h\u1ecdc M\u1ef9 \u0111\u00e3 l\u00e0m m\u1ed9t th\u00ed nghi\u1ec7m r\u1ea5t th\u00fa v\u1ecb. H\u1ecd \u0111\u1eb7t nh\u1eefng chi\u1ebfc gi\u01b0\u1eddng r\u1ea5t \u00eam \u1edf trong gian ph\u00f2ng kh\u00f4ng c\u00f3 \u00e2m thanh, kh\u00f4ng c\u00f3 \u00e1nh s\u00e1ng, c\u00e1ch bi\u1ec7t ho\u00e0n to\u00e0n v\u1edbi xung quanh. N\u1ebfu ng\u01b0\u1eddi n\u00e0o s\u1eb5n s\u00e0ng th\u00ed nghi\u1ec7m s\u1ed1ng trong c\u0103n ph\u00f2ng \u0111\u01a1n \u0111\u1ed9c \u0111\u00f3 4 ng\u00e0y th\u00ec h\u1ecd s\u1ebd \u0111\u01b0\u1ee3c th\u01b0\u1edfng m\u1ed9t m\u00f3n ti\u1ec1n r\u1ea5t l\u1edbn. Nh\u01b0ng nh\u1eefng ng\u01b0\u1eddi tham gia th\u00ed nghi\u1ec7m kh\u00f4ng ch\u1ecbu \u0111\u1ef1ng n\u1ed5i hai ng\u00e0y \u0111\u00e3 ph\u1ea3i b\u1ea5m chu\u00f4ng xin ng\u1eebng th\u00ed nghi\u1ec7m. Nguy\u00ean l\u00e0 trong gian ph\u00f2ng qu\u00e1 y\u00ean t\u0129nh, t\u1ea5t c\u1ea3 gi\u1ed1ng nh\u01b0 \u0111\u00f4ng \u0111\u1eb7c l\u1ea1i, khi\u1ebfn cho ng\u01b0\u1eddi ta c\u1ea3m th\u1ea5y th\u1ea7n ch\u1ebft s\u1eafp \u0111\u1ebfn, kh\u00f4ng t\u00e0i n\u00e0o ch\u1ecbu n\u1ed5i.<\/p>\n\n\n\n
C\u1ee5c H\u00e0ng kh\u00f4ng v\u0169 tr\u1ee5 M\u1ef9 c\u0169ng ti\u1ebfn h\u00e0nh m\u1ed9t th\u00ed nghi\u1ec7m t\u01b0\u01a1ng t\u1ef1. H\u1ecd \u0111\u01b0a ng\u01b0\u1eddi th\u00ed nghi\u1ec7m v\u00e0o m\u1ed9t khoang t\u00e0u \u0111\u00f3ng k\u00edn ho\u00e0n to\u00e0n kh\u00f4ng c\u00f3 ti\u1ebfng \u0111\u1ed9ng. K\u1ebft qu\u1ea3 ph\u00e1t hi\u1ec7n th\u1ea5y ng\u01b0\u1eddi th\u00ed nghi\u1ec7m c\u00f3 th\u1ec3 nghe \u0111\u01b0\u1ee3c ti\u1ebfng tim \u0111\u1eadp v\u00e0 ti\u1ebfng m\u00e1u ch\u1ea1y trong huy\u1ebft qu\u1ea3n, khi c\u1eed \u0111\u1ed9ng c\u00f3 th\u1ec3 nghe \u0111\u01b0\u1ee3c ti\u1ebfng c\u1ecd x\u00e1t c\u1ee7a c\u00e1c kh\u1edbp x\u01b0\u01a1ng, ti\u1ebfng s\u1ed9t so\u1ea1t c\u1ee7a qu\u1ea7n \u00e1o. N\u1eeda gi\u1edd sau, th\u00ednh gi\u00e1c c\u1ee7a ng\u01b0\u1eddi th\u00ed nghi\u1ec7m c\u00e0ng nh\u1ea1y c\u1ea3m h\u01a1n, ch\u1ec9 c\u1ea7n th\u1edf nh\u1eb9 c\u0169ng \u0111\u00e3 c\u1ea3m th\u1ea5y nh\u01b0 l\u00e0 m\u1ed9t ti\u1ebfng h\u1eaft h\u01a1i. M\u1ed9t gi\u1edd sau ng\u01b0\u1eddi th\u00ed nghi\u1ec7m c\u1ea3m th\u1ea5y ho\u1ea3ng s\u1ee3 v\u00f4 c\u00f9ng. Sau 3 \u2013 4 ti\u1ebfng \u0111\u1ed3ng h\u1ed3 th\u00ec l\u00ed tr\u00ed d\u1ea7n d\u1ea7n m\u1ea5t h\u1ebft.<\/p>\n\n\n\n
K\u1ebft qu\u1ea3 th\u00ed nghi\u1ec7m n\u00e0y ch\u1ee9ng t\u1ecf con ng\u01b0\u1eddi kh\u00f4ng th\u1ec3 s\u1ed1ng trong m\u00f4i tr\u01b0\u1eddng tuy\u1ec7t \u0111\u1ed1i kh\u00f4ng c\u00f3 ti\u1ebfng \u0111\u1ed9ng.<\/p>\n\n\n\n
X\u01b0a nay, ta ch\u1ec9 th\u01b0\u1eddng nghe n\u00f3i ti\u1ebfng ch\u1ea3y r\u00f3c r\u00e1ch c\u1ee7a khe n\u01b0\u1edbc c\u00f3 l\u1ee3i cho s\u1ee9c kh\u1ecfe. Ti\u1ebfng chim k\u00eau, ti\u1ebfng c\u00f4n tr\u00f9ng, ti\u1ebfng r\u00f3c r\u00e1ch\u2026 \u0111\u1ec1u l\u00e0 nh\u1eefng kh\u00fac nh\u1ea1c giao h\u01b0\u1edfng uy\u1ec3n chuy\u1ec3n c\u1ee7a thi\u00ean nhi\u00ean. N\u00f3 kh\u00f4ng nh\u1eefng hun \u0111\u00fac n\u00ean t\u00ednh t\u00ecnh c\u1ee7a con ng\u01b0\u1eddi, khi\u1ebfn cho tinh th\u1ea7n tho\u1ea3i m\u00e1i m\u00e0 c\u00f2n l\u00e0 nh\u1eefng k\u00edch th\u00edch c\u00f3 l\u1ee3i cho h\u1ec7 th\u1ed1ng th\u1ea7n kinh, nh\u1edd \u0111\u00f3 m\u00e0 c\u1ea3i thi\u1ec7n \u0111\u01b0\u1ee3c ch\u1ee9c n\u0103ng \u0111i\u1ec1u ti\u1ebft c\u1ee7a c\u01a1 th\u1ec3.<\/p>\n\n\n\n
Do \u0111\u00f3 c\u00f3 th\u1ec3 th\u1ea5y ch\u00fang ta \u0111\u1ed3ng th\u1eddi v\u1edbi vi\u1ec7c tr\u1eeb b\u1ecf \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n th\u00ec c\u0169ng \u0111\u00f2i h\u1ecfi m\u1ed9t m\u00f4i tr\u01b0\u1eddng c\u00f3 \u00e2m thanh \u0111\u1eb9p, h\u00e0i h\u00f2a, tuy\u1ec7t \u0111\u1ed1i kh\u00f4ng ph\u1ea3i l\u00e0 \u201cm\u1ed9t th\u1ebf gi\u1edbi kh\u00f4ng c\u00f3 \u00e2m thanh\u201d.<\/p>\n\n\n\n
V\u00ec sao n\u00f3i s\u00f3ng h\u1ea1 \u00e2m (th\u1ea5p h\u01a1n s\u00f3ng \u00e2m thanh) c\u0169ng l\u00e0m ch\u1ebft ng\u01b0\u1eddi?<\/p>\n\n\n\n
N\u0103m 1948, t\u00e0u ch\u1edf h\u00e0ng c\u1ee7a H\u00e0 Lan khi \u0111i qua m\u1ed9t eo bi\u1ec3n \u0111\u00e3 g\u1eb7p b\u00e3o. Sau \u0111\u00f3 to\u00e0n th\u1ec3 th\u1ee7y th\u1ee7 \u0111\u1ec1u ch\u1ebft m\u1ed9t c\u00e1ch im l\u1eb7ng. N\u0103m 1960, tr\u00ean bi\u1ec3n \u0110\u1ea1i T\u00e2y D\u01b0\u01a1ng c\u00f3 ng\u01b0\u1eddi ph\u00e1t hi\u1ec7n th\u1ea5y c\u00f3 hai can\u00f4 l\u00eanh \u0111\u00eanh tr\u00ean m\u1eb7t bi\u1ec3n, tr\u00ean \u0111\u00f3 kh\u00f4ng c\u00f3 ng\u01b0\u1eddi. N\u0103m 1970, con t\u00e0u mang t\u00ean Mil\u00e2yt\u01a1n c\u1ee7a M\u1ef9 m\u1ea5t t\u00edch tr\u00ean bi\u1ec3n. N\u0103m 1973, con t\u00e0u Anna c\u1ee7a Na Uy c\u0169ng \u0111\u1ed9t nhi\u00ean m\u1ea5t t\u00edch, bi\u1ec7t v\u00f4 \u00e2m t\u00edn.<\/p>\n\n\n\n
V\u00ec sao l\u1ea1i ph\u00e1t sinh h\u00e0ng lo\u1ea1t th\u1ea3m \u00e1n n\u00e0y? K\u1ebb g\u00e2y t\u1ed9i l\u00e0 ai? Th\u00f4ng qua \u0111i\u1ec1u tra ph\u00e2n t\u00edch, cu\u1ed1i c\u00f9ng \u0111\u00e3 l\u00e0m s\u00e1ng t\u1ecf \u201chung th\u1ee7\u201d g\u00e2y ra c\u00e1c tai h\u1ecda n\u00e0y ch\u00ednh l\u00e0 s\u00f3ng th\u1ea5p h\u01a1n s\u00f3ng \u00e2m thanh trong kh\u00f4ng kh\u00ed g\u00e2y n\u00ean.<\/p>\n\n\n\n
S\u00f3ng th\u1ea5p h\u01a1n s\u00f3ng \u00e2m thanh l\u00e0 lo\u1ea1i s\u00f3ng tai ng\u01b0\u1eddi kh\u00f4ng nghe th\u1ea5y \u0111\u01b0\u1ee3c. Tai ng\u01b0\u1eddi ch\u1ec9 c\u00f3 th\u1ec3 nghe th\u1ea5y s\u00f3ng \u00e2m trong ph\u1ea1m vi t\u1ea7n s\u1ed1 t\u1eeb 20 \u2013 20.000 Hz. S\u00f3ng \u00e2m v\u01b0\u1ee3t qu\u00e1 20.000 Hz g\u1ecdi l\u00e0 s\u00f3ng si\u00eau \u00e2m, s\u00f3ng \u00e2m th\u1ea5p h\u01a1n 20 Hz g\u1ecdi l\u00e0 s\u00f3ng h\u1ea1 \u00e2m. C\u1ea3 hai lo\u1ea1i s\u00f3ng n\u00e0y tai ng\u01b0\u1eddi \u0111\u1ec1u kh\u00f4ng nghe \u0111\u01b0\u1ee3c.<\/p>\n\n\n\n
Ngu\u1ed3n ph\u00e1t sinh s\u00f3ng h\u1ea1 \u00e2m c\u00f3 th\u1ec3 chia th\u00e0nh ngu\u1ed3n ph\u00e1t sinh thi\u00ean nhi\u00ean v\u00e0 ngu\u1ed3n nh\u00e2n t\u1ea1o. Ngu\u1ed3n ph\u00e1t sinh thi\u00ean nhi\u00ean bao g\u1ed3m gi\u00f3 b\u00e3o, ti\u1ebfng s\u00e9t, gi\u00f3 l\u1ed1c, m\u01b0a \u0111\u00e1, s\u00f3ng ng\u1ea7m do \u0111\u1ed9ng \u0111\u1ea5t, n\u00fai l\u1eeda ho\u1ea1t \u0111\u1ed9ng, s\u1ea1t l\u1edf n\u00fai, k\u00edch quang ph\u00f3ng \u0111i\u1ec7n, b\u00e3o t\u1eeb M\u1eb7t Tr\u1eddi v.v.. t\u1ea7n s\u1ed1 th\u1ea5p h\u01a1n 0,1 Hz. Ngu\u1ed3n nh\u00e2n t\u1ea1o bao g\u1ed3m ti\u1ebfng m\u00e1y bay, xe ch\u1ea1y v\u1edbi t\u1ed1c \u0111\u1ed9 cao, m\u00e1y quay nhanh, s\u00f3ng vi l\u01b0\u1ee3ng, bom h\u1ea1t nh\u00e2n, t\u1ea7n s\u1ed1 t\u1eeb 1-5 Hz. B\u1ea3n th\u00e2n c\u01a1 th\u1ec3 ng\u01b0\u1eddi c\u0169ng c\u00f3 th\u1ec3 ph\u00e1t sinh s\u00f3ng h\u1ea1 \u00e2m nh\u01b0 ti\u1ebfng th\u1edf, t\u1ea7n s\u1ed1 t\u1eeb 0,25 \u2013 0,3 Hz, ti\u1ebfng tim \u0111\u1eadp t\u1ea7n s\u1ed1 l\u00e0 1,2 Hz.<\/p>\n\n\n\n
S\u00f3ng h\u1ea1 \u00e2m c\u00f3 th\u1ec3 truy\u1ec1n \u0111i r\u1ea5t xa m\u00e0 n\u0103ng l\u01b0\u1ee3ng suy gi\u1ea3m r\u1ea5t \u00edt, \u0111\u00f3 l\u00e0 m\u1ed9t trong nh\u1eefng \u0111\u1eb7c tr\u01b0ng v\u1eadt l\u00ed \u0111\u1ed9c \u0111\u00e1o c\u1ee7a n\u00f3. S\u00f3ng h\u1ea1 \u00e2m d\u01b0\u1edbi 10 Hz c\u00f3 th\u1ec3 v\u01b0\u1ee3t qua r\u1eebng, qua bi\u1ec3n truy\u1ec1n \u0111i h\u00e0ng ngh\u00ecn kil\u00f4met. M\u00f9a h\u00e8 n\u0103m 1983, m\u1ed9t tr\u1eadn n\u00fai l\u1eeda ho\u1ea1t \u0111\u1ed9ng ph\u00e1t ra s\u00f3ng h\u1ea1 \u00e2m \u0111\u00e3 \u0111i qua ba v\u00f2ng Tr\u00e1i \u0110\u1ea5t v\u1edbi th\u1eddi gian 108 gi\u1edd, c\u00e1c vi kh\u00ed \u00e1p k\u1ebf tr\u00ean to\u00e0n th\u1ebf gi\u1edbi \u0111\u1ec1u ghi \u0111\u01b0\u1ee3c s\u1ef1 ho\u1ea1t \u0111\u1ed9ng c\u1ee7a n\u00f3. N\u0103m 1986, t\u00e0u con thoi \u201cng\u01b0\u1eddi th\u00e1ch th\u1ee9c\u201d c\u1ee7a M\u1ef9 n\u1ed5 tr\u00ean kh\u00f4ng \u0111\u00e3 ph\u00e1t ra s\u00f3ng h\u1ea1 \u00e2m k\u00e9o d\u00e0i 12 gi\u1edd 53 ph\u00fat, \u0111i qua qu\u00e3ng \u0111\u01b0\u1eddng 14.300 km, \u0111\u01b0\u1ee3c m\u00e1y \u0111o c\u1ee7a C\u1ee5c nghi\u00ean c\u1ee9u H\u1ecdc vi\u1ec7n \u00e2m thanh Vi\u1ec7n khoa h\u1ecdc Trung Qu\u1ed1c thu \u0111\u01b0\u1ee3c.<\/p>\n\n\n\n
S\u1ef1 l\u1ee3i h\u1ea1i c\u1ee7a s\u00f3ng h\u1ea1 \u00e2m c\u00f2n \u1edf ch\u1ed7 s\u1ee9c xuy\u00ean s\u00e2u c\u1ee7a n\u00f3 r\u1ea5t m\u1ea1nh. N\u00f3 c\u00f3 th\u1ec3 xuy\u00ean qua nh\u1eefng c\u00f4ng tr\u00ecnh ki\u1ebfn tr\u00fac ki\u00ean c\u1ed1, ngay c\u1ea3 lo\u1ea1i m\u0169 \u0111\u1eb7c bi\u1ec7t c\u1ee7a nh\u00e0 du h\u00e0nh v\u0169 tr\u1ee5 c\u0169ng kh\u00f4ng th\u1ec3 n\u00e0o che ch\u1eafn \u0111\u01b0\u1ee3c. S\u00f3ng h\u1ea1 \u00e2m r\u1ea5t c\u00f3 h\u1ea1i cho s\u1ee9c kh\u1ecfe c\u1ee7a con ng\u01b0\u1eddi v\u00ec t\u1ea7n s\u1ed1 c\u1ee7a n\u00f3 kh\u1edbp v\u1edbi t\u1ea7n s\u1ed1 ri\u00eang c\u1ee7a c\u01a1 th\u1ec3. M\u1ed9t khi s\u00f3ng h\u1ea1 \u00e2m m\u1ea1nh t\u00e1c d\u1ee5ng v\u00e0o c\u01a1 th\u1ec3 th\u00ec s\u1ebd g\u00e2y n\u00ean s\u1ef1 rung \u0111\u1ed9ng m\u00e3nh li\u1ec7t c\u1ee7a m\u1ed9t s\u1ed1 c\u01a1 quan, th\u1eadm ch\u00ed g\u00e2y n\u00ean c\u1ed9ng h\u01b0\u1edfng. T\u1eeb \u0111\u00f3 khi\u1ebfn cho con ng\u01b0\u1eddi c\u1ea3m th\u1ea5y v\u00e1ng \u0111\u1ea7u, \u00f9 tai, n\u00f4n nao, m\u1ea5t ng\u1ee7, th\u1ea7n kinh th\u00e1c lo\u1ea1n, tay ch\u00e2n t\u00ea d\u1ea1i, m\u1ea5t c\u1ea3m gi\u00e1c, \u0111\u1eb7c bi\u1ec7t l\u00e0 s\u00f3ng h\u1ea1 \u00e2m m\u1ea1nh c\u00f2n c\u00f3 th\u1ec3 g\u00e2y ch\u1ebft ng\u01b0\u1eddi t\u1ea1i ch\u1ed7. H\u00e0ng lo\u1ea1t th\u1ea3m k\u1ecbch v\u1eeba k\u1ec3 \u1edf tr\u00ean ch\u00ednh l\u00e0 s\u00f3ng h\u1ea1 \u00e2m \u0111\u1eb7c bi\u1ec7t m\u1ea1nh trong t\u1ef1 nhi\u00ean k\u00edch th\u00edch g\u00e2y n\u00ean. C\u00e1c nh\u00e0 khoa h\u1ecdc Ph\u00e1p \u0111\u00e3 nghi\u00ean c\u1ee9u r\u1ea5t nhi\u1ec1u v\u1ec1 s\u00f3ng h\u1ea1 \u00e2m v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn: s\u00f3ng h\u1ea1 \u00e2m trong b\u1ea5t c\u1ee9 tr\u01b0\u1eddng h\u1ee3p n\u00e0o c\u0169ng \u0111\u1ec1u c\u00f3 h\u1ea1i. N\u00f3i n\u00f3 l\u00e0 k\u1ebb gi\u1ebft ng\u01b0\u1eddi kh\u00f4ng c\u00f3 ti\u1ebfng \u0111\u1ed9ng c\u0169ng kh\u00f4ng c\u00f3 g\u00ec l\u00e0 qu\u00e1 \u0111\u00e1ng.<\/p>\n\n\n\n
T\u1eeb kho\u00e1: S\u00f3ng h\u1ea1 \u00e2m. S\u00f3ng si\u00eau \u00e2m.<\/p>\n","protected":false},"excerpt":{"rendered":"
D\u00e2n c\u01b0 s\u1ed1ng \u1edf th\u00e0nh ph\u1ed1 \u0111\u1ec1u mong c\u00f3 m\u1ed9t m\u00f4i tr\u01b0\u1eddng \u00edt ti\u1ebfng \u0111\u1ed9ng. Ti\u1ebfng \u1ed3n \u0111\u00e3 tr\u1edf th\u00e0nh v\u1ea5n \u0111\u1ec1 \u00f4 nhi\u1ec5m r\u1ea5t l\u1edbn c\u1ee7a th\u00e0nh ph\u1ed1. Nh\u01b0ng con ng\u01b0\u1eddi c\u0169ng kh\u00f4ng th\u1ec3 s\u1ed1ng trong m\u00f4i tr\u01b0\u1eddng tuy\u1ec7t \u0111\u1ed1i kh\u00f4ng c\u00f3 \u00e2m thanh. Ch\u1ec9 trong m\u00f4i tr\u01b0\u1eddng c\u00f3 ti\u1ebfng \u0111\u1ed9ng h\u00e0i h\u00f2a v\u00e0 […]<\/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":[15,17],"tags":[],"class_list":["post-9470","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-moi-truong"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/9470","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=9470"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/9470\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=9470"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=9470"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=9470"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}