H U C N G DAN QUAN LI Sl/DUNG CAC LOAl BAI TAP TINH HUONG SUDUNG TRONG DAY HOC K? THUAT NONG NGHI§P dTRUNG HOC CO Sd 1 Ddt van de Bai tgp tinh huong (BTTH) Id nhu''''ng tlnh hu6ng xdy ra trong qud trinh[.]
H U C N G DAN QUAN LI Sl/DUNG CAC LOAl BAI TAP TINH HUONG SUDUNG TRONG DAY HOC K? THUAT NONG NGHI§P dTRUNG HOC CO Sd Ddt van de Bai tgp tinh huong (BTTH) Id nhu'ng tlnh hu6ng xdy qud trinh dgy hge dugc ciu tnic dudi dgng bai tgp Dd Id mgt cau true ngon ngii md hinh hod yfiu cau ve kT thugt, bipn phdp, phuang phdp dgy hpc md yfiu cdu dd dang tiem an chua dugc bgc Ig trudc ngudi dgy khdng ed kinh nghipm Mfl hinh ndy cd kha ndng thiic tinh nhu cau phdn tich nhiing khia cgnh cd lien quan dfin mo hinh de cd djnh hudng ddp iing yeu cdu Khi giai BTTH thi khflng nhirng giup HS khdc sdu kifin thiic ma cdn ren luypn cdc ky nang de van dyng thuc tifin cugc song Tuy nhien, hifin BTTH van chua dugc sir dyng nhieu day hgc ki thuat nflng nghifip (KTNN) d THCS Vi vgy can phdi tdng cudng sii dyng chiing dfi nang cao hipu qud dgy hpe bg mfln, ddp iing mye tifiu dgy hgc ndi chung vd day hoc KTNN ndi rieng d THCS Cdc loai BTTH day hpc KTNN* THCS Hipn cd nhifiu each khdc dfi phdn logi BTTH, dgy hpc KTNN d THCS, chiing toi phdn logi theo cac cdeh sau day: a Phdn logi difa vdo ddc diern vd tinh chdt cda mdu thudn xudt Men * BTTH tao tu mau thuan gifta kifin thiic cu va kifin thiic mdi Logi tlnh huong ndy xuit hifin sy khdng phii hgp giiia kien thiic cu (cdi dd biet) vd kien thiic mdi (cdi chua bi^t) Khi tlnh hu6ng xuit hipn, HS nhgn thiy cd khfa cgnh mdi ve tri thiic vd mgng muon dugc thda mdn nhu cau khdm phd Gidi quyet mdu thuin ndy bdng cdeh vgn dyng nguon tri thiic mdi bp sung de ldm rfl, gidi thich van de d^t Vi dy: M0t lan dgc bdo, bgn Thdo dugc bifit cd dgi va triing Id hai cde nguyen nhdn ldm gidm ndng suat Ilia nfin dugc cfl gido hdi "Lam thfi nao dfi ndng suat Ilia dgt miic cao nhat?" thi bgn Thao trd ldi: "Dfi ed nang suat lua cao nhdt gieo trflng cdn phdi diet hfit cfln triing va cfl dgi trfin rugng liia vi chung Id nguyfin nhan Idm gidm ndng suat" Mpt sfl bgn dong y nhung cd mgt sd bgn khdng ddng y vdi cau trd ldi cua bgn Thdo Em cd ddng y vdi cdu trd ldi cua bgn Thdo khflng? Tgi sao? * BTTH t^o tu mdu thuan giiia ly thuyfit vd thye tifin Tinh hudng ndy xudt hifin nhung bieu hifin cua thye tien da dgng, phong phii khflng hgp ly vdi ly thuyfit khoa hgc tuang ling Mau Uiuan ndy dgt cho HS mgt nhifim vi^ cin phdi nfli nhip hai diu cdu ly thuyet va thye tien mpt each phu_ hgp Gidi quyet mau thuan ndy la phdi tim nhiing yfiu tfl, dieu kifin da chi phfli, anh hudng dfin bifiu hifin cua Ngdy nhgn bdi 20/9/2012; Ngdy duyei dang 25/11/2012 • TAP CHI THICT BI GIAO Dl^ - 50 88 -12/2012 TS NguySn Duan Tru&ng DHSP - DHHui thye tien Vi dy: Trong tiet hpc v^ bdi *Tdc dyng ciia phan bdn tr6ng trgt" d ldp 7E, nghe CO gido ndi "phdn hOii eg dung de bdn Idt" thi bgn Thing d Idp dd chg ring "phan hihi CO Cling cd the bdn thiic" vi bgn ay thiy bo mp bdn nhu the trfin rugng liia nhd minh Theo em bgn Thing ndi diing khdng? Tgi sao? * BTTH tgo tir mau thuan xudt hipn bdi sy lya chpn Mau thuan ndy sinh HS diing trudc sy lya chon mgt phuang dn sd nhieu phuang dn khdc md xem phuang an ndo cung cd ve hgp ly Gidi quyfit mdu thuan bdng each phan tich, loai bd nhiing cai khdng ban chat dfi tim cau trd ldi dimg nhat Vi dp: Khi ndi vfi d$c diem phd hgi cua trimg, cd y khac nhau: Y kifin 1: Cfln trimg pha hgi m^nh rihat d giai dogn sau non; Y kifin 2: Cfln tning pha hgi mgnh nhit d giai dogn sau trudng thdnh Em sfi chgn y kifin nao? Tai sao? * BTTH tgo bdi mau thuan giQ-a ban chit va hipn tugng (nghjch ly) Mdu thuan xudt hipn cd su trdi ngugc gifta yfiu tfl ban chat vdi hi^n tugng, sy kipn tuong iing, hogc trai ngugc giGa nhiing hipn tugng vdi quan nipm thong thudng vd kifin thiic ma HS da hilu trudc dd Difiu se tgo sy xung d0t tu cua HUONG DAN QUAN LI s u DUNG HS va chinh sy nghjch I^ lgi loi cufln su td md ciia HS HS phdi di tim hi^u, phdn tich hifn tugng, phfi phdn quan diem sai dfi di dfin cai chan ly, cai bdn chat cua vdn dfi Vi dy: Bifit phan bdn cd tdc dung ldm tdng nang suat cay trflng vd chat lugng nflng sdn nfin bgn Nam da bdn rat nhifiu phdn dgm cho vudn cd chua cua minh vdi suy_ ngh! rdng cdng bdn phan nhifiu thi cd ehua cdng cho nhieu qud vd qud edng to, ndng suat se cao Nhung sau bdn nhieu phdn dam mflt thdi gian thi nhifiu cay cd chua bj heo Id, qudn Id va chdm phdt trifin Bgn Nam khflng hifiu vi cd chua lgi bj nhu vgy Em hay giup ban Nam gidi dap nhiing thac mac * BTTH tgo bdi mau thuan giua nguyen nhdn vd kfit qud (bdt ngd) Tmh huong xdy xuat hifin mdu thudn giiia nguyfin nhdn vd kfit qud cua nd, dieu gdy nfin su bat ngd, ngodi dy dodn jogic ciia HS Cdeh giai quyfit la lam sdng to nguyen nhdn ea bdn nhat ddn dfin kfit qud Vi dy: Nha bde Ndm ed thira rugng cung dipn tich, thira ruflng thii nhdt Id ddt cat pha, thiia raflng thii hai la dat thit nang Cung thdi difim, trqng cimg difiu kipn thdi tifit giflng nhau, bdc Ndm cho vao hai mpng lua trfin mpt Iugng nudc nhu Sau mflt thai gian kifim tra thi bac i y thiy miic nudc d thiia rugng thii hai lgi nhieu han miic nudc d thita ruflng thir nhit Bdc Nam dem chuyfin ndy kfi vdi ban Thing (chdu bdc Ndm) d Idp 70 nhung bgn Thing khflng tin vi bgn i y cho ring lugng nudc ban dau ciia hai thiia rugng bing nhau, dilu ki^n thdi tilt giflng thi lugng nudc mat di sau mgt thdi gian eiia hai thiia rugng phdi nhu Theo em, bgn Thdng ndi nhu vgy cd dung khdng? Tgi sao? b Dua vdo mgc dich ly lugn dgy hgc * BTTH dfi hinh thdnh kien thiic, ky nang mdi BTTH chiia dyng ngi dung kifin thiic, ky ndng mdi dfli vdi HS Khi gidi dugc cde bdi tgp ndy Id HS s6 ITnh hgi kifin thiic mdi vd hinh thdnh k$> ndng mdi Vi dy: Trong cugc thi "Dfl vui dfi hgc" d ldp 7B, dgi nfiu cdu dfl cho dgi nhu sau: Cd chdu A, B, C, D bdng nhau: chdu A: chiia dat set; chau B; chiia dat cat; chdu C: chiia ddt thit; chau D: chiia dat cat pha Cho vao chdu A, B, C, D lugng nude giong nhau, cimg dieu kien thdi tifit nhu Sau mdt thdi gian thi lugng nudc cdn lai chdu nao la nhieu nhat, chau ndo it nhat? Biet rang lupng dat mfli chau Id bdng Dpi tra ldi: Khong the biet dugc vi khflng thfi dugc lugng nudc cdn lgi cac chgu.Theo em dgi trd ldi nhu vgy diing hay sai? Neu em la thdnh vifin cua dgi em sg trd ldi nhu thfinao? * BTTH dfi cimg cfl, hoan thipn vd he thong hod kifin thiic Logi bai tap thudng sii dyng sau HS ITnh hpi kifin thiic mdi ,nhung cdn rdi rgc, dan lfi nham de HS khdi qudt hda, h^ thflng hda kifin thiic, dong thdi van dung kien thiic vao hoan canh tuong ty Vi du: Trudc tha cd vao ao nuoi, bgn Quflc dp va dO pH ciia nudc ao vdi ket qud: dp (do bdng dia sech xi): 25 cm; dp pH: Tii dd bgn Quflc kfit lugn: Ao nufli dd hodn toan phii hgp dfi thd cd nuoi Theo em, kfit lugn cua bgn Quflc chinh xdc chua? Tgi sao? * BTTH de kifim tra ddnh gia kfit qud hgc tgp ciia HS Logi BTTH ndy dimg dfi kifim tra ddnh gid ket qud hpe tap ciia HS sau da ITnh hpi mpt kien thirc nhdt dinh (mpt ehuang, mOt bdi ) Vi dy: Cd mau ddt phdng thi nghifim da bi mat nhan nen khflng nhan biet chinh xdc togi ddt cua timg mdu Khi sir dung^ phuang phdp ve tay thi mau cho kfit qua sau day: Mau 1: ve dugc thdnh thdi nhung dirt dogn; mau 2: vfi dugc thdi, ufln khong cd vfit nut; mau 3: vfi dugc thdi, ufln bi dirt dogn; mdu 4: vfi dugc thdi, ufln cd vfit mit Neu chi can cii vao ket qua ve tay nhu tren thi em cd thfi xdc djnh dugc logi dat cua mfli man trfin khflng? c Phdn logi BTTH theo logi ky ndng nhgn thuc cua HS Sit dyng BTTH frong dgy hgc cd tdc dyng ren luyfin cdc ky ndng nhgn thiic cho HS nhu: Ky nang phan tich tdng hgp, ky nang so sdnh, ky nang khdi quat hda, ky ndng suy ludn Chiing tdi tgm quy udc: BTTH dimg dfi ren luyfin ky nang nhgn thiic ndo cua HS thi ggi tfin theo ky nang nhan thirc dd Theo each se cd cdc logi BTTH: BTTH phan tich - tflng hgp, BTTH so sdnh, BTTH khdi quat hda, BTTH suy lugn TAP CHI THIET BI GIAO Dgc-SO 88-12/2012 • HUONG DAN QUAN Li si/DUNG * BTTH phdn tich - t6ng hgp Phan tich vd tong hgp Id hai m^t cua rngt qud trinh tu thflng nhit cd su lifin hp m^t thiet vdi Tong hgp sg bO ban dau cho an tugng chung ve doi tugng, nhd dd md xdc dinh dugc phuang hudng phdn tich cho_d6i tugng Tir sy phan tich dfli tugng sfi giiip HS CO sy nhgn thiic day dii ban ve doi tugng, phan tich cdng sdu thi sy tong hgp cuoi ciing cang cag, cdng day du Sy tflng hgp hodn chinh sS dnh hudng den ehit lugng ciia sy phdn tich tifip theo Cii nhu vdy, nhgn thiic ngdy cdng tien sau vao bdn chat ciia sy vgt vd hifin tugng Sii dung BTTH Id mgt frong nhirng bipn phap quan frgng dfi ren luyfin k^ ndng phan - tich tflng hop cho HS frong day hgc KTNN THCS Vl du: Khi cfl giao hdi "Muon hieu qua phong tni sau benh hgi cao nhat thi phai su dyng bien phdp phong trir nao?" Ban Hung da fra ldi "Mufln hieu qua phdng trir sau benh hai cao nhdt thi phai sir dyng tflng hgp cdc bifin phdp phdng trir" Cfl giao yfiu cau ban Hung chiing minh y kifin cua minh nhung bgn iy limg tiing Nfiu em la Hung thi em se chiing minh nhu thfi nao? * BTTH so sanh So sanh Id syphan tich nhiing difim giflng vd khdc rihau giiia cdc dfli tugng nham phan logi sy vat hien tugng nhiing logi khac Tuy myc dich md phugng phap so sanh cd thfi ngng vfi tim diem giflng hay khac Vi dy: Trong de kifim fra mgt tiet, cfl giao de: "Hdy 42 tim dilm khdc giiia quy trinh fr^ng edy cd biu vd quy trinh edy rl trin" Cd m^t bgn ldm bdi vdi cdu trd ldi Id: "Quyfrinhtr^ng edy cd biu khdc vdi quy trinh edy re tran id cd budc "rgch vd bau" Theo em cdu trd ldi dd hodn todn chinh xdc chua? Tgi sao? * BTTH khdi qudt hda Khdi qudt hda Id hogt dflng trf tup cap cao nhim gom cdc doi tugng cd ciing thugc tinh vd bdn chat vdo mflt nhdm Dd Id qud trlnh chuyin tir cdi dan nhit len cdi chung Ky ndng giiip HS tdch dugc cdi chung, cdi ban chdt, nhChig mfli lien h^ ben mang tinh quy lugt cua tdi lipu nghifin ciiu, hpc tdp Vi du: Cd mgt bgn^ cho rdng, dya vdo cdc bdng so Hpu sau day (bdng va bdng 2) se biet dugc vai frd cua giflng vat nuoi frong chan nuoi Em hay chiing minh y kifin cua bgn dd * BTTH suy lugn Suy lu$n la hinh thiic ciia tu nhd dd nit phan dodn mdi tir mflt hay nhilu phdn dodn theo cdc quy tdc logic xdc djnh can cii vdo cdeh thiic l§p lu|in, suy lugn dugc chia thdnh cdc logi suy lugn khdc nhu suy lugn suy dien, suy luan quy ngp Suy lugn suy dien Id suy lugn frong dd lgp lugn hi cdi chung dfin cai rifing, cdi dan nhat Suy ludn quy ngp Id suy lugn frong dd lgp lugn tir cdi rifing, cdi dan nhit dfin cdi ehung BTTH rfin luypn kf ndng suy luan cho HS Id bai tgp dgt yfiu cau HS phai qua dudng suy lugn mdi ed ldi gidi hgp 1^ frong thdi gian nhat djnh Vi dy: Trong mgt bai kifim fra d ldp 7G ndm ngodi, cfl giao bdi tap: "Cd logi dit: 1) Dit cdt pha; 2) Ddt thjt ndng; 3) Dit set; 4) Dit thjt trung binh; 5) (Xem tiep trang 44) Gi6ng gd Nang suat trimg (qui/nim/con) Giri - 100 Ga Dong Tao 50-70 Ga mia 55-60 G4 4c 70-80 Gitre 40-50 G i Plymouth 150-160 Ga Gold — Line 250 - 300 G i Rohde dfi 180-200 Gi New Hamp 200 - 220 Shire Bdng Ndng sudt trung cua mgt so gidng gd' Giong b6 B6 Hoslsteni Friesian (Ha Lan) B6 Sahival Bd Jersey Bo nau Thuy ST (Brown Swiss) Bo zebu Ti I§ m9 sfta (%) 3,2 - 3,7 4-4,5 5,6-6 3,5-4 52 Bang Ti li ma sira cua mgt so giong bo' • T^PCHlTHllTBtGlAODgc-S688-12/2012 HUONG DAN QUAN LI SUDUNG iO GIAC' L'UC VA bk'jTALI [lA MO'I 1,'ONti HOA VA HOl '-'HU NUKiA \'I£T N.-UI TRirONGCAOPANGSirPH.AM Dodap Tudo HwihpiiiK l>\Nt S'n Ntl ll«^ t^cng d n ['•iv r lt> to d v r g J - J H HjL rr ^ ^ - - • - - ' NoMinL 11.1 T^ ^ Lop l.'ao dAnt Ni D \'ir«lunvu*liv( Anh Hang sO uIAO DVC VA MO TAO HA I I'M CONG H O \ VA HOI ( HU NGIflA \"I£T N.UI IRI'OUG MO BANG W PR«I I'of l.|i Til H.IJI phll' r)AN(;B\Mr 11 V H«v»tfn U Thl Anh NgJMinh B-Vi-w- Nmndi C«^ b « b t»ir« r dj« 9iM> Til I gg HtTii Lop