Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn<\/p>\n\n\n\n
\u00c2m thanh l\u00e0 m\u1ed9t trong nh\u1eefng l\u0129nh v\u1ef1c m\u00e0 v\u1eadt l\u00fd 7 t\u00ecm hi\u1ec3u r\u1ea5t nhi\u1ec1u. N\u1ebfu nh\u01b0 b\u1ea1n mu\u1ed1n t\u00ecm hi\u1ec3u nh\u1eefng ki\u1ebfn th\u1ee9c c\u01a1 b\u1ea3n<\/a> v\u00e0 n\u00e2ng cao v\u1ec1 \u0111\u1ed9 cao c\u1ee7a \u00e2m; h\u00e3y \u0111\u1ecdc ti\u1ebfp b\u00e0i vi\u1ebft n\u00e0y nh\u00e9. Ch\u00fang t\u00f4i mang \u0111\u1ebfn cho b\u1ea1n r\u1ea5t nhi\u1ec1u th\u00f4ng tin th\u00fa v\u1ecb \u0111\u1ec3 b\u1ea1n t\u00ecm hi\u1ec3u, tham kh\u1ea3o. Tin r\u1eb1ng nh\u1eefng chia s\u1ebb b\u1ed5 \u00edch n\u00e0y s\u1ebd gi\u00fap b\u1ea1n \u00edt nhi\u1ec1u trong vi\u1ec7c t\u00edch l\u0169y ki\u1ebfn th\u1ee9c. C\u00f2n ch\u1ea7n ch\u1edd g\u00ec n\u1eefa, c\u00f9ng t\u00ecm hi\u1ec3u ngay v\u1edbi ch\u00fang t\u00f4i th\u00f4i n\u00e0o!<\/p>\n\n\n\n \u0110\u1ed9 cao c\u1ee7a \u00e2m l\u00e0 g\u00ec?<\/p>\n\n\n\n \u0110\u1ed9 cao c\u1ee7a \u00e2m l\u00e0 g\u00ec?<\/p>\n\n\n\n Nhi\u1ec1u ng\u01b0\u1eddi th\u1eafc m\u1eafc v\u1ec1 kh\u00e1i ni\u1ec7m \u0111\u1ed9 cao c\u1ee7a \u00e2m. Ta th\u01b0\u1eddng th\u1ea5y nh\u1eefng \u0111\u1ed9 tr\u1ea7m, \u0111\u1ed9 b\u1ed5ng kh\u00e1c nhau khi nghe nh\u1eefng d\u1ee5ng c\u1ee5 \u00e2m nh\u1ea1c. C\u00f3 th\u1ec3 hi\u1ec3u r\u1eb1ng, \u0111\u00e2y ch\u00ednh l\u00e0 \u0111\u1eb7c tr\u01b0ng sinh l\u00fd, \u0111\u01b0\u1ee3c quy\u1ebft \u0111\u1ecbnh t\u1eeb nh\u1eefng \u0111\u1eb7c tr\u01b0ng v\u1eadt l\u00fd c\u1ee7a \u00e2m. \u0110\u00f3 ch\u00ednh l\u00e0 t\u1ea7n s\u1ed1.<\/p>\n\n\n\n \u0110\u1ed9 cao c\u1ee7a \u00e2m ph\u1ee5 thu\u1ed9c v\u00e0o t\u1ea7n s\u1ed1 c\u1ee7a \u00e2m thanh ho\u1eb7c ph\u1ee5 thu\u1ed9c v\u00e0o s\u1ed1 dao \u0111\u1ed9ng trong m\u1ed7i gi\u00e2y c\u1ee7a v\u1eadt, ph\u00e1t ra \u00e2m thanh \u1ea5y.<\/p>\n\n\n\n \u0110\u1ed9 cao \u00e2m thanh ph\u1ee5 thu\u1ed9c v\u00e0o \u0111\u00e2u?<\/p>\n\n\n\n Ta \u0111\u00e3 bi\u1ebft \u1edf b\u00e0i h\u1ecdc tr\u01b0\u1edbc, \u0111\u00f3 l\u00e0 \u0111\u1ed9 to c\u1ee7a \u00e2m s\u1ebd ph\u1ee5 thu\u1ed9c v\u00e0o m\u1ee9c c\u01b0\u1eddng \u0111\u1ed9 \u00e2m. C\u00f2n \u0111\u1ed9 cao c\u1ee7a \u00e2m g\u1eafn li\u1ec1n v\u1edbi t\u1ea7n s\u1ed1. N\u1ebfu nh\u01b0 \u0111\u1ed9 dao \u0111\u1ed9ng c\u1ee7a v\u1eadt ph\u00e1t ra \u00e2m thanh kh\u00e1c nhau, ch\u00fang s\u1ebd \u1ea3nh h\u01b0\u1edfng t\u1edbi \u0111\u1ed9 cao kh\u00e1c nhau. C\u00f3 th\u1ec3 k\u1ec3 \u0111\u1ebfn r\u1eb1ng ch\u00fang mang \u0111\u1ebfn nh\u1eefng \u00e2m thanh tr\u1ea7m, b\u1ed5ng c\u1ef1c th\u00fa v\u1ecb. V\u00ed d\u1ee5 nh\u01b0 sau:<\/p>\n\n\n\n Khi v\u1eadt dao \u0111\u1ed9ng nhanh v\u00e0 c\u00f3 t\u1ea7n s\u1ed1 dao \u0111\u1ed9ng kh\u00e1 l\u1edbn. Th\u00ec \u00e2m ph\u00e1t ra s\u1ebd \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u00e2m c\u00e0ng cao, ho\u1eb7c \u00e2m c\u00e0ng b\u1ed5ng.<\/p>\n\n\n\n Khi v\u1eadt dao \u0111\u1ed9ng ch\u1eadm v\u1edbi t\u1ea7n s\u1ed1 dao \u0111\u1ed9ng kh\u00e1 nh\u1ecf. Th\u00ec \u00e2m ph\u00e1t ra s\u1ebd \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u00e2m c\u00e0ng tr\u1ea7m ho\u1eb7c c\u00e0ng th\u1ea5p.<\/p>\n\n\n\n Si\u00eau \u00e2m v\u00e0 h\u1ea1 \u00e2m l\u00e0 g\u00ec?<\/p>\n\n\n\n Nh\u1eafc \u0111\u1ebfn kh\u00e1i ni\u1ec7m \u0111\u1ed9 cao c\u1ee7a \u00e2m, ch\u1eafc ch\u1eafn nhi\u00eau ng\u01b0\u1eddi t\u00f2 m\u00f2 v\u1ec1 si\u00eau \u00e2m v\u00e0 h\u1ea1 \u00e2m. \u0110\u00e2y l\u00e0 nh\u1eefng kh\u00e1i ni\u1ec7m th\u01b0\u1eddng \u0111\u01b0\u1ee3c nh\u1eafc \u0111\u1ebfn b\u1edfi ch\u00fang g\u1eafn li\u1ec1n v\u1edbi t\u1ea7n s\u1ed1. H\u01a1n n\u1eefa, ch\u00fang c\u0169ng ph\u00e1c h\u1ecda chi ti\u1ebft v\u1ec1 s\u1ef1 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn s\u1ee9c kh\u1ecfe con ng\u01b0\u1eddi.<\/p>\n\n\n\n C\u00e1 voi ph\u00e1t ra s\u00f3ng si\u00eau \u00e2m<\/p>\n\n\n\n Si\u00eau \u00e2m l\u00e0 g\u00ec?<\/p>\n\n\n\n Nh\u1eefng lo\u1ea1i \u00e2m c\u00f3 t\u1ea7n s\u1ed1 tr\u00ean 20000Hz \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 si\u00eau \u00e2m. Tai nghe c\u1ee7a con ng\u01b0\u1eddi ch\u1ec9 c\u00f3 th\u1ec3 nghe \u0111\u01b0\u1ee3c \u00e2m c\u00f3 t\u1ea7n s\u1ed1 t\u1eeb 20Hz \u0111\u1ebfn 20000Hz. B\u1edfi th\u1ebf, n\u1ebfu v\u01b0\u1ee3t ngo\u00e0i ng\u01b0\u1ee1ng n\u00e0y th\u00ec tai c\u1ee7a ng\u01b0\u1eddi kh\u00f4ng th\u1ec3 nghe \u0111\u01b0\u1ee3c.<\/p>\n\n\n\n Si\u00eau \u00e2m l\u00e0 \u00e2m thanh c\u00f3 t\u1ea7n s\u1ed1 cao h\u01a1n so v\u1edbi t\u1ea7n s\u1ed1 t\u1ed1i \u0111a tai ng\u01b0\u1eddi c\u00f3 th\u1ec3 nghe. N\u00f3i c\u00e1ch d\u1ec5 hi\u1ec3u h\u01a1n, \u0111\u00e2y l\u00e0 \u00e2m thanh con ng\u01b0\u1eddi kh\u00f4ng th\u1ec3 nghe \u0111\u01b0\u1ee3c. Nh\u1eefng lo\u00e0i c\u00e1 nh\u01b0 c\u00e1 heo ho\u1eb7c c\u00e1 voi th\u01b0\u1eddng s\u1eed d\u1ee5ng \u00e2m thanh n\u00e0y. Ch\u00fang c\u00f3 th\u1ec3 giao ti\u1ebfp v\u1edbi nhau m\u00e0 con ng\u01b0\u1eddi kh\u00f4ng th\u1ec3 nghe \u0111\u01b0\u1ee3c.<\/p>\n\n\n\n H\u1ea1 \u00e2m l\u00e0 g\u00ec?<\/p>\n\n\n\n Nh\u1eafc \u0111\u1ebfn h\u1ea1 \u00e2m, \u0111\u00e2y c\u0169ng l\u00e0 \u00e2m m\u00e0 con ng\u01b0\u1eddi kh\u00f4ng th\u1ec3 nghe th\u1ea5y. Th\u1ebf nh\u01b0ng kh\u00e1c v\u1edbi si\u00eau \u00e2m, t\u1ea7n s\u1ed1 c\u1ee7a h\u1ea1 \u00e2m l\u1ea1i nh\u1ecf h\u01a1n 20Hz. B\u1edfi th\u1ebf, h\u1ea1 \u00e2m th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 d\u1ef1 b\u00e1o \u0111\u1ed9ng \u0111\u1ea5t. Ngo\u00e0i ra, ch\u00fang c\u0169ng \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 kh\u1ea3o s\u00e1t c\u00e1c t\u1ea7ng \u0111\u1ecba ch\u1ea5t hay l\u00e0 c\u00e1ch \u1ee9ng d\u1ee5ng trong y t\u1ebf.<\/p>\n\n\n\n Gi\u1ea3i th\u00edch chi ti\u1ebft v\u1ec1 \u0111\u1ed9 cao c\u1ee7a \u00e2m<\/p>\n\n\n\n Nh\u1eefng th\u00f4ng tin ch\u00fang t\u00f4i \u0111\u01b0a t\u1edbi b\u00ean tr\u00ean ph\u00f9 h\u1ee3p v\u1edbi kh\u1ed1i l\u01b0\u1ee3ng ki\u1ebfn th\u1ee9c h\u1ecdc sinh<\/a>. Nh\u1eefng em h\u1ecdc sinh<\/a> kh\u1ed1i l\u1edbp 7 ch\u1ec9 c\u1ea7n \u0111\u1ecdc t\u1edbi nh\u1eefng th\u00f4ng tin ph\u00eda tr\u00ean l\u00e0 \u0111\u1ee7. Th\u1ebf nh\u01b0ng v\u1edbi nh\u1eefng ng\u01b0\u1eddi mu\u1ed1n t\u00ecm hi\u1ec3u r\u00f5 h\u01a1n v\u1ec1 t\u00ednh ch\u1ea5t c\u1ee7a \u00e2m. Ngo\u00e0i ra mu\u1ed1n m\u1edf r\u1ed9ng t\u01b0 duy v\u1ec1 l\u0129nh v\u1ef1c n\u00e0y, b\u1ea1n n\u00ean \u0111\u1ecdc th\u00eam chia s\u1ebb d\u01b0\u1edbi \u0111\u00e2y nh\u00e9. Ch\u00fang \u0111\u01b0\u1ee3c nh\u00ecn nh\u1eadn d\u01b0\u1edbi g\u00f3c nh\u00ecn c\u1ee7a chuy\u00ean gia<\/a>, v\u1edbi nhi\u1ec1u t\u1eeb chuy\u00ean ng\u00e0nh h\u01a1n!<\/p>\n\n\n\n Th\u00f4ng tin v\u1ec1 cao \u0111\u1ed9<\/p>\n\n\n\n Cao \u0111\u1ed9 hay c\u00f2n g\u1ecdi l\u00e0 \u0111\u1ed9 cao c\u1ee7a \u00e2m. Ch\u00fang l\u00e0 m\u1ed9t c\u1ea3m gi\u00e1c c\u1ee7a th\u00ednh gi\u00e1c, b\u1edfi th\u1ebf ng\u01b0\u1eddi nghe c\u00f3 th\u1ec3 t\u1ef1 \u1ea5n \u0111\u1ecbnh \u0111\u01b0\u1ee3c nh\u1eefng \u00e2m thanh. Ch\u1ec9 c\u1ea7n th\u00f4ng qua v\u1ecb tr\u00ed t\u01b0\u01a1ng \u0111\u1ed1i tr\u00ean th\u01b0\u1edbc \u0111o d\u1ef1a v\u00e0o t\u1ea7n s\u1ed1 rung l\u00e0 ch\u1ee7 y\u1ebfu. Ngo\u00e0i ra, cao \u0111\u1ed9 s\u1ebd c\u00f3 quan h\u1ec7 c\u1ef1c k\u1ef3 ch\u1eb7t ch\u1ebd v\u1edbi t\u1ea7n s\u1ed1. Tuy nhi\u00ean, m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang l\u1ea1i kh\u00f4ng \u0111\u01b0\u1ee3c coi l\u00e0 t\u01b0\u01a1ng \u0111\u01b0\u01a1ng.<\/p>\n\n\n\n Cao \u0111\u1ed9 \u0111\u01b0\u1ee3c coi l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m khoa h\u1ecdc mang t\u00ednh kh\u00e1ch quan. C\u00f2n t\u1ea7n s\u1ed1 th\u00ec \u0111\u01b0\u1ee3c coi l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m khoa h\u1ecdc c\u00f3 t\u00ednh ch\u1ee7 quan. C\u00f3 th\u1ec3 th\u1ea5y, b\u1ea3n ch\u1ea5t c\u1ee7a c\u00e1c s\u00f3ng \u00e2m s\u1ebd kh\u00f4ng c\u00f3 cao \u0111\u1ed9. C\u00f2n dao \u0111\u1ed9ng c\u1ee7a ch\u00fang kh\u00f4ng th\u1ec3 \u0111o \u0111\u1ea1c \u0111\u01b0\u1ee3c v\u1edbi t\u1ea7n s\u1ed1.<\/p>\n\n\n\n D\u01a1i nghe \u0111\u01b0\u1ee3c h\u1ea1 \u00e2m<\/p>\n\n\n\n \u0110\u1ed9 cao c\u1ee7a \u00e2m \u0111\u01b0\u1ee3c c\u1ea3m nh\u1eadn ra sao?<\/p>\n\n\n\n C\u00f3 th\u1ec3 th\u1ea5y r\u1eb1ng \u0111\u1ed9 cao c\u1ee7a \u00e2m \u0111\u01b0\u1ee3c c\u1ea3m nh\u1eadn r\u1ea5t m\u01a1 h\u1ed3 v\u00e0 kh\u00e1 ph\u1ee9c t\u1ea1p. Ng\u01b0\u1eddi nghe kh\u00e1c nhau s\u1ebd c\u1ea3m nh\u1eadn \u0111\u01b0\u1ee3c m\u1ee9c \u0111\u1ed9 kh\u00e1c nhau gi\u1eefa c\u00e1c n\u1ed1t nh\u1ea1c. C\u00f3 th\u1ec3 bi\u1ebft \u0111\u01b0\u1ee3c t\u1ea7n s\u1ed1 ch\u00ednh c\u1ee7a \u00e2m l\u00e0 bao nhi\u00eau b\u1edfi c\u00e1c d\u1ee5ng c\u1ee5 \u0111o \u0111\u1ea1c. Th\u1ebf nh\u01b0ng c\u1ea3m nh\u1eadn v\u1ec1 cao \u0111\u1ed9 v\u1eabn c\u00f3 th\u1ec3 kh\u00e1c nhau gi\u1eefa c\u00e1c ng\u01b0\u1eddi nghe.<\/p>\n\n\n\n Nguy\u00ean nh\u00e2n x\u1ea3y ra s\u1ef1 vi\u1ec7c n\u00e0y \u0111\u00f3 l\u00e0 do s\u00f3ng h\u00e0i, b\u1ed3i \u00e2m ho\u1eb7c nh\u1eefng nguy\u00ean nh\u00e2n kh\u00e1c. Trong m\u1ed9t s\u1ed1 ho\u00e0n c\u1ea3nh nh\u1ea5t \u0111\u1ecbnh, s\u1ef1 ph\u00e2n bi\u1ec7t t\u1ea7n s\u1ed1 kh\u00e1c nhau c\u1ee7a c\u00e1c n\u1ed1t nh\u1ea1c s\u1ebd g\u1eb7p kh\u00f3 kh\u0103n.<\/p>\n\n\n\n Ng\u01b0\u1ee1ng ph\u00e2n bi\u1ec7t l\u00e0 g\u00ec?<\/p>\n\n\n\n Ng\u01b0\u1ee1ng ph\u00e2n bi\u1ec7t hay c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 ng\u01b0\u1ee1ng c\u1ee7a s\u1ef1 thay \u0111\u1ed5i m\u00e0 ta c\u00f3 th\u1ec3 c\u1ea3m nh\u1eadn \u0111\u01b0\u1ee3c. V\u1edbi ng\u01b0\u1ee1ng n\u00e0y, ch\u00fang ph\u1ee5 thu\u1ed9c v\u00e0o l\u01b0\u1ee3ng thay \u0111\u1ed5i c\u1ee7a t\u1ea7n s\u1ed1 \u00e2m thanh. N\u1ebfu t\u1ea7n s\u1ed1 c\u1ee7a \u00e2m thanh d\u01b0\u1edbi 500 Hz, ng\u01b0\u1ee1ng ph\u00e2n bi\u1ec7t n\u1eb1m \u1edf kho\u1ea3ng 3 Hz v\u1edbi s\u00f3ng sin. V\u00e0 l\u00e0 1 Hz \u0111\u1ed1i v\u1edbi nh\u1eefng \u00e2m thanh ph\u00fac t\u1ea1p. N\u1ebfu nh\u01b0 \u1edf ng\u01b0\u1ee1ng tr\u00ean 1000 Hz th\u00ec c\u00f3 ng\u01b0\u1ee1ng ph\u00e2n bi\u1ec7t \u0111\u1ed1i v\u1edbi s\u00f3ng sin v\u00e0o kho\u1ea3ng 10 cent.<\/p>\n\n\n\n Nh\u1eefng ng\u01b0\u1ee1ng n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c th\u1eed nghi\u1ec7m b\u1eb1ng c\u00e1ch ph\u00e1t ra 2 \u00e2m li\u00ean ti\u1ebfp. \u0110i\u1ec1u n\u00e0y s\u1ebd xem r\u1eb1ng ng\u01b0\u1eddi nghe c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c s\u1ef1 kh\u00e1c bi\u1ec7t \u0111\u1ed9 cao c\u1ee7a \u00e2m hay kh\u00f4ng. Ngo\u00e0i ra, ng\u01b0\u1ee1ng n\u00e0y s\u1ebd tr\u1edf n\u00ean nh\u1ecf h\u01a1n n\u1ebfu nh\u01b0 ph\u00e1t hai \u00e2m c\u00f9ng m\u1ed9t l\u00fac. L\u00fd do l\u00e0 b\u1edfi ng\u01b0\u1eddi nghe kh\u00f3 ph\u00e2n bi\u1ec7t \u0111\u01b0\u1ee3c hi\u1ec7n t\u01b0\u1ee3ng ph\u00e1ch.<\/p>\n\n\n\n T\u1ed5ng s\u1ed1 cao \u0111\u1ed9 c\u00f3 th\u1ec3 c\u1ea3m nh\u1eadn trong ph\u1ea1m v\u1ecb ng\u01b0\u1ee1ng nghe l\u00e0 1400 v\u1edbi con ng\u01b0\u1eddi. N\u1ebfu trong \u00e2m giai \u0111i\u1ec7u h\u00f2a \u00e2m kho\u1ea3ng 16 Hz \u0111\u1ebfn 16000 Hz th\u00ec l\u00e0 120 n\u1ed1t.<\/p>\n\n\n\n B\u00e0i t\u1eadp v\u1ec1 \u0111\u1ed9 cao c\u1ee7a \u00e2m<\/p>\n\n\n\n M\u1ed9t s\u1ed1 b\u00e0i t\u1eadp d\u01b0\u1edbi \u0111\u00e2y s\u1ebd gi\u00fap c\u00e1c em hi\u1ec3u h\u01a1n kh\u00e1i ni\u1ec7m \u0111\u1ed9 cao c\u1ee7a \u00e2m. H\u00e3y tham kh\u1ea3o ngay nh\u00e9.<\/p>\n\n\n\n B\u00e0i 1: M\u1ed9t v\u1eadt khi dao \u0111\u1ed9ng s\u1ebd ph\u00e1t ra \u00e2m c\u00f3 t\u1ea7n s\u1ed1 l\u00e0 50 Hz. M\u1ed9t v\u1eadt kh\u00e1c khi dao \u0111\u1ed9ng s\u1ebd ph\u00e1t ra \u00e2m c\u00f3 t\u1ea7n s\u1ed1 l\u00e0 70 Hz. V\u1eadt n\u00e0o c\u00f3 kh\u1ea3 n\u0103ng dao \u0111\u1ed9ng nhanh h\u01a1n? V\u1eadt n\u00e0o s\u1ebd ph\u00e1t ra \u00e2m th\u1ea5p h\u01a1n? H\u00e3y \u00e1p d\u1ee5ng nh\u1eefng \u0111i\u1ec1u \u0111\u00e3 h\u1ecdc \u1edf v\u1eadt l\u00fd 7, tr\u1ea3 l\u1eddi nh\u1eefng c\u00e2u h\u1ecfi tr\u00ean.<\/p>\n\n\n\n B\u00e0i 2: Khi bay, nhi\u1ec1u con v\u1eadt s\u1ebd c\u00f3 th\u00f3i quen v\u1ed7 c\u00e1nh, t\u1eeb \u0111\u00f3 ph\u00e1t ra \u00e2m thanh.<\/p>\n\n\n\n a, Con mu\u1ed7i hay ph\u00e1t ra \u00e2m cao h\u01a1n so v\u1edbi con ong \u0111\u1ea5t. V\u1eady trong 2 con c\u00f4n tr\u00f9ng n\u00e0y, con n\u00e0o s\u1ebd v\u1ed7 c\u00e1nh nhi\u1ec1u h\u01a1n?<\/p>\n\n\n\n b, T\u1ea1i sao ch\u00fang ta kh\u00f4ng th\u1ec3 nghe \u0111\u01b0\u1ee3c \u00e2m thanh do c\u00e1nh c\u1ee7a con chim khi bay t\u1ea1o ra?<\/p>\n\n\n\n L\u1eddi gi\u1ea3i b\u00e0i t\u1eadp<\/p>\n\n\n\n Sau khi \u0111\u1ecdc c\u00e2u h\u1ecfi ch\u00fang t\u00f4i \u0111\u01b0a ra v\u00e0 t\u1ef1 m\u00ecnh gi\u1ea3i \u0111\u00e1p, c\u00e1c em c\u00f3 th\u1ec3 \u0111\u1ecdc l\u1eddi gi\u1ea3i n\u00e0y. \u0110\u00e2y l\u00e0 l\u1eddi gi\u1ea3i ch\u00ednh x\u00e1c cho b\u00e0i t\u1eadp, \u0111\u1ea3m b\u1ea3o s\u1ebd ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c em.<\/p>\n\n\n\n B\u00e0i 1: T\u1ea7n s\u1ed1 l\u00e0 s\u1ed1 dao \u0111\u1ed9ng \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n trong 1s. B\u1edfi th\u1ebf, hai v\u1eadt n\u00e0y s\u1ebd l\u00e0 m\u1ed9t v\u1eadt th\u1ef1c hi\u1ec7n dao \u0111\u1ed9ng 50 l\u1ea7n, v\u1eadt th\u1ef1c hi\u1ec7n dao \u0111\u1ed9ng 70 l\u1ea7n. Ch\u1eafc ch\u1eafn v\u1eadt 2 dao \u0111\u1ed9ng nhanh h\u01a1n.<\/p>\n\n\n\n V\u00ec \u0111\u1ed9 cao c\u1ee7a \u00e2m v\u00e0 t\u1ea7n s\u1ed1 t\u1ec9 l\u1ec7 thu\u1eadn, n\u00ean v\u1eadt 1 c\u00f3 \u00e2m th\u1ea5p h\u01a1n<\/p>\n\n\n\n B\u00e0i 2:<\/p>\n\n\n\n a, Con mu\u1ed7i ph\u00e1t ra \u00e2m cao h\u01a1n ong, n\u00ean con mu\u1ed7i s\u1ebd v\u1ed7 c\u00e1nh nhi\u1ec1u h\u01a1n con ong<\/p>\n\n\n\n b, V\u00ec t\u1ea7n s\u1ed1 c\u1ee7a c\u00e1nh chim nh\u1ecf h\u01a1n 20 Hz, n\u1eb1m ngo\u00e0i ng\u01b0\u1ee1ng nghe con ng\u01b0\u1eddi. N\u00ean con ng\u01b0\u1eddi kh\u00f4ng nghe \u0111\u01b0\u1ee3c \u00e2m ph\u00e1t ra t\u1eeb ti\u1ebfng \u0111\u1eadp c\u00e1nh chim.<\/p>\n\n\n\n Ph\u00e2n bi\u1ec7t \u0111\u1ed9 cao c\u1ee7a \u00e2m<\/p>\n\n\n\n Tr\u00ean \u0111\u00e2y l\u00e0 nh\u1eefng th\u00f4ng tin ch\u00fang t\u00f4i mang \u0111\u1ebfn cho b\u1ea1n v\u1ec1 \u0111\u1ed9 cao c\u1ee7a \u00e2m. \u0110\u1eebng qu\u00ean tham kh\u1ea3o nh\u1eefng b\u00e0i vi\u1ebft kh\u00e1c tr\u00ean website c\u1ee7a ch\u00fang t\u00f4i \u0111\u1ec3 c\u00f3 \u0111\u01b0\u1ee3c nh\u1eefng th\u00f4ng tin t\u1ed1t nh\u1ea5t nh\u00e9. V\u00ed d\u1ee5 b\u00e0i vi\u1ebft v\u1ec1 g\u01b0\u01a1ng c\u1ea7u l\u00f5m r\u1ea5t hay, b\u1ea1n n\u00ean tham kh\u1ea3o ngay!<\/p>\n\n\n\n Xem v\u00e0 t\u00ecm hi\u1ec3u ngay c\u00e1c b\u00e0i vi\u1ebft kh\u00e1c c\u00f9ng Vietlearn<\/p><\/blockquote>\n\n\n\n V\u00e2\u0323t Ly\u0301 l\u1edbp 12: B\u00ed quy\u1ebft \u00f4n luy\u1ec7n n\u00e2ng cao \u0111i\u1ec3m s\u1ed1 \u201cd\u1ec5 d\u00e0ng\u201d<\/p>\n\n\n\n Ti\u1ebfng Anh l\u1edbp 6: Gi\u00fap con l\u00e0m quen v\u1edbi ch\u01b0\u01a1ng tr\u00ecnh m\u1edbi<\/p>\n\n\n\n H\u1ecdc To\u00e1n c\u00f9ng Vietlearn: L\u00e0m quen v\u1edbi s\u1ed1 nguy\u00ean \u00e2m<\/p>\n\n\n\n Ti\u1ebfn<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":" Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn \u00c2m thanh l\u00e0 m\u1ed9t trong nh\u1eefng l\u0129nh v\u1ef1c m\u00e0 v\u1eadt l\u00fd 7 t\u00ecm hi\u1ec3u r\u1ea5t nhi\u1ec1u. N\u1ebfu nh\u01b0 b\u1ea1n mu\u1ed1n t\u00ecm hi\u1ec3u nh\u1eefng ki\u1ebfn th\u1ee9c c\u01a1 b\u1ea3n v\u00e0 n\u00e2ng cao v\u1ec1 \u0111\u1ed9 cao c\u1ee7a \u00e2m; h\u00e3y \u0111\u1ecdc ti\u1ebfp b\u00e0i vi\u1ebft n\u00e0y nh\u00e9. Ch\u00fang t\u00f4i mang \u0111\u1ebfn cho b\u1ea1n r\u1ea5t […]<\/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":[4],"tags":[],"class_list":["post-1025","post","type-post","status-publish","format-standard","hentry","category-trung-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/1025","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=1025"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/1025\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=1025"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=1025"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=1025"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}