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DAY HOG GAG KHAI NIEM TIN HOG 0 TRUNG HOC PHO THONG THEO HUONG TICH CUC HOA CAC HOAT DONG LE VIET CHUNG* uc tieu eua bd mdn Tin hgc (TH) d tnrdng tamg hpc phdthdng (THPT) la trang bi cho hgcsinh(HS)mg[.]
DAY HOG GAG KHAI NIEM TIN HOG TRUNG HOC PHO THONG THEO HUONG TICH CUC HOA CAC HOAT DONG LE VIET CHUNG* uc tieu eua bd mdn Tin hgc (TH) d tnrdng dan mdtsdkie'nthiiredeaeem nhu: "ehia de trj", "cit tamg hpc phdthdng (THPT) la trang bi cho tifng phan" "tinh che", rat gan gui vdi khai niem hgcsinh(HS)mgtcich tuang ddedhithdng can tim hieu cickhiiniem cabin nhatdmucddphdthdng veTH 2) Hoat dgng trinh bay khainiem Tif nhifng Tuy nhien, thue te'viee day hpe bd mdn-nha't la dac diem, tinh chat cd lien quan, gan gui, GV yeu day eac khai niem TH - cho thay dedat dupe mue tieu cau HS manh dan trinh bay, md ta khai niem theo tren la rat khd khan dd'i vdi giao vien (GV) TH each hieu cua minh Cd the tha'y, cae khai niem ve Dieu bit ngudn tif nguyen nhan: GV khdng "tin hpc" da cd nhieu each dinh nghTa khac thiet kedugc eic hoatddng tich cue nhim giiip HS tim (nhu: Tin hpe la gi? Dif lieu la gi? Chuang trinh eon fd/va A'/ja/r7p/?akhai niem maehichii trpng day tn/c tie'p la gi?, ) tif nhieu ngudn (sach nghien cu'U, eae khai niem thdng qua thuyet trinh, dpe chep, giai Internet, ) Vi vay, GV can tinh y de hudng each thich, minh hpa, mang tinh ehii quan, ap dat trinh bay eua HS tie'p can vdi ndi dung, khai niem De khic phue han chenay, theo ehiing tdi, GVTH dupe trinh bay sach giao khoa (SGK); dieu can van dung quan diem hoatddng day eac chinh, su'a chifa cho HS each lap luan, hanh van, su khainiem qua viee thii'tki'cic hoat ddng day hgc nhu dung eae ngdn ngi; ehinh xac, logic; gidi thieu (hoac nhifng tinh hudng supham CIJ the, giup H S cd ca hdi dn lai) nhifng khai niem tuang ti/nam he thd'ng tie'p can, lam quen vdi khai niem, tien tdi ehii ddng eae khai niem (nhu: dif lieu - ca sd dif lieu - eau true nim bat khai niem mdt each tieh cue dif lieu; bai toan - thuat toan - chuong trinh, ) Mot so hoat dong tich cue day hoc 3) Hoat dgng nhan dang khainiem H len nay, cac khai niem TH nhieu GV d THPT van chua hieu mpt each thau 1) Hoat dgng tie'p can khai niim GV khdng dao ve "ngoai dien" va "ndi ham" cua mpt khai niem tn/c tie'p trinh bay khai niem ma thdng qua eac vi du, - dac biet la eac khai niem TH Dieu khien cau chuyen, hinh anh thuc te, eau hdi, cd lien quan HS khd phat hien mdt dd'i tupng nao thude de'n mpt sddae diem, dau hieu eiia khai niem; so "ngoai dien" hoac cd an chifa eae dau hieu dac sanh vdi mdt so khai niem tuong tu', de HScd dieu trung thude "ndi ham" eiia khai niem dang xet Theo kien tie'p can dan vdi khai niem GV ed the si) dung ehiing tdi, mdt each trinh bay don gian se giiip ea cae vi du, cau chuyen, vao bai hpe mdi hoac thay va trd de' hieu hon neu hay phan tieh khai khi"chuyen mue" bai hpc cd cae khai niem niem la nen xem xet mdt each tuong dd'i: "np/ftafT? Ching han, deday khai niem "thdng tin", GV se ii ndidung edn "ngoai diin ii hinh thuc thehien khdng dua djnh nghTa ma cd the ke eac eau cua khii niim" Thdng thudng, GV cho HS nhan dang khai niem chuyen ve nhtrng nhan vat nd'i tieng ITnh vuc cdng nghe thdng tin (hoac nhirng ehu de khac ed thdng qua eac vi du, phan vi du, tim kie'm ldi, khic lien quan ) Qua nhifng thdng tin nhu vay, nhirng phue sai lam de khic sau ve ban chat cua khai niem khai niem se dan djnh hinh d cae em Hoac day 4) Hoat dgng thehien khai niem G V td' chii'c khai niem "chuang trinh con", GV ed the gidi thieu eho HS tao hang loat eae "dd'i tupng" nhim thda eho HS ve "su phan edng lao ddng" cae nha may d mdt day chuyen tu ddng hda de hinh * Khoa Tin hoc, fiai hoc sir pham Da Nang (kil-2/2014) Tap chi Giao due so 327 51 man dung djnh nghTa ve mdt khai niem thdng qua eac vi du, hinh anh, bai tap, Hoatddng giup HS sang td han ve "ban chat eua djnh nghTa" vacdthesi} dung eae khai niem hpe cac ndi dung kie'n thuc tie'p theo (nhu d eac bai toan dan gian hoac mang tinh td'ng hpp) Tuy nhien, khdng phai nao GV cung can thue hien dii hoatddng tren Vdi eae khai niem don gian, khdng qua phire tap hoac qua trifu tupng thi GV cd the chi can td chii'c hoat ddng: tie'p can, nhan dang vathehien khai niem Mpt so vi du vlec thiet ke, xay dung cac hoat dong day hpc mpt khai niem TH 1) Day khainiem "Thuat toan" (tiit 4, chuang 1, TH 10) Day la mdt khai niem mdi va khd dd'i vdi HS Idp 10 Cac em se khd hie'u dupe mdt each ehinh xac khai niem "thuat toan" neu viee day khai niem khdng rd rang, eu the Rait nhieu HS khdng hieu "viet thuat toan tim nghiem phuang trinh bae ax^ + bx + c = 0" ed gidng nhu giai bai toan vdi cae so a, b, e cu the hay khdng? Hoac GV yeu eau HS "tim thuat toan" eho bai toan nao dd, cac em lai thudng nham lin "khai niem thuattoan" vdi "bai toan" hoac khdng rd viet thuat toan de lam gi va tai phai viet Sau day la each thiet ke cae hoat ddng day khai niem a) Tiip can khii niim - Hoat ddng cua GV: + Cho bai toan: "Hay xac djnh each tim qua cam cd trpng lupng nang nha't mdt rd' cam cd n trai cam (n>0) bing cai can dia"; -I- Hudng dan: "Input" va "output" ciia bai toan la gi? (2 khai niem vifa hpc xong); + Yeu cau HS tra Idi bing each ghi dudi dang cac bude liet ke; - Hoan chinh eac bude va tien hanh thif nghiem - Hoatddng cua HS: + Cae nhdm tien hanh xac djnh bing viee ehi nhifng each thue ed the (cac each xac djnh cd the sai va khdng bit bude trinh bay nhu "thuat toan" ma tuong tu nhu each trinh bay Idi giai eiia mdt bai toan binh thudng); -i- Neu cae bude tien hanh xac djnh vdi GV (day la su tie'p can vdi khai niem thuat toan); -i- So sanh phan trinh bay cua GV vdi ket qua cua ban than de nJt ket luan Cac hoat ddng se giiip HS bude dau ed the nam dupe viee xac dinh Idi giai ciia mdt bai toan nao dd cd the gpi la "thuat toan" 52 Tap chi Giao due so 327 b) Trinh bay khii niim - Hoatddng cua G V: + Khuyen khich HS trinh bay each hieu biet ciia minh ve khai niem "thuattoan" ma khdng can tham khao SGK; -i- Dieu ehinh, sua chira kjp thdi Idi trinh bay khai niem eua cae em va hudng de'n mdt djnh nghTa chinh xac nhu SGK - Hoatddng eua HS: - Trinh bay rd rang each hieu eiia minh ve khai niem; - Trinh bay lai khai niem mot each rd rang, chinh xac sau GV da nhan xetva sira chifa c) Nhan dang khii niem • Hoat ddng cua G I/.' - Cho HS lam bai tap sd (trang 44, TH 10) de khang djnh day khdng phai la "thuat toan", tif dd lam rd hon tinh "hiiu han" cua khai niem nay; - Yeu cau HS kie'm tra lai vi du md dau de khang djnh "tinh hifu han, tinh xac djnh va tinh diing" ciia thuattoan; - Nhan manh tinh chat cung la dac diem quan trpng cua mdt thuat toan; - De nghj HS so sanh ve "thuat toan giai mdt bai toan" vdi viee giai mdt bai toan thdng thudng - Hoatddng cua WS + Xac dinh day sd bai tap khdng phai la thuat toan vi eac bude khdng dijfng; -I- Xac dinh dupe eac bude khitien hanh thuattoan (d vi du tren) la lam cho thuat toan ket thue hoac xac djnh mdt bude tie'p theo; - Xac djnh bai toan diing "vdi bat kin trii cam cho trudd" Cac hoatddng tren giiip HS nhan dang mpt thuat toan theo nhifng tinh chat ma nd dupe xac djnh va "Idp" cae bai toan eiing thuat toan (nhu xac djnh: HS cd chieu cao nha't Idp; hd gia dinh tieu thu dien eao nha't khu vuc; so Idn nha't n soda eho, ) Day cung la each GV xay dung "ndi ham" va "ngoai dien" eua khai niem thuattoan eho HS d) The hien khii niem 'Thuattoan" • Hoatddng cua G K-+ Yeu eau HS tutim mpt vai thuat toan rut tif thuc te hoac chuong trinh hpe (nhu: thuat toan nau cam, lam nha, khdi dpng may tinh; thuat toan tim nghiem PTB2; thuat toan ve dudng trung tn/e ciia doan thing AB eho tnrdc bing thude ke va eompa) va trinh bay; - Hoat ddng cd the' td' chii'c theo nhdm "tich tie" hoac nhdm co ban; - Sua chua, dieu chinh eae sai sdt HS trinh bay khai niem - Hoat dgng cua HS: - Tim mpt bai toan, xay dung thuat toan va ehung minh thuat toan ed thda (kil-2/2014) man cae tinh chat ciia nd khdng? - Trinh bay thuat Cae hoat ddng se giiip HS nim rd hon ve ban toan dudi dang liet ke rd rang chat, each khai bao eua mang de' cd the xac djnh, 2) Day khai niim "mang mot chieu" (tiet 11, nhan dien dung mdt cau tnJc mang cho trude; bie't ap dung eho eac bai toan Hen quan de'n eae dtf lieu cd chuang'4,THU)' cau tme mang thue tema minh edthexay dung a) Tiep can khii niem d) Thehien khii niim -Hoat ddng cua GV: + Neu bai toan: "Viet chuong -Hoatddng cua GV.Neu mdtsd bai toan, yeu cau trinh tim so Idn nhat sd nguyen a,,a2,a3 cho torde"; - Md rdng bai toan "eho n sda,,a^, a„; + Chi HS khai bao dif lieu eua bai toan thdng qua cau true nhifng han chekhi viet chuong trinh theo each mang Vi du: 1) Khai bao mdt mang cd 10 phan tu; "khai bao" thdng thudng (dai ddng, de nham lin, khd mdi phan tif cd kieu dif lieu la kieu ki tu, dupe danh ehi kie'm soat, ); + Cho HS "tiem can" dan vdi khai niem sd bit dau tif 0; 2) Khai bao dif lieu eho bai toan: viet qua cae kie'n thifc nhu: hifu han phan tutif ai, , an; chuong trinh tim qua eam cd trpng lupng nang phan tufcung kieu; phan tu'dupc xac djnh theo chisd, nha't mdt rd' cam cd n trai cam cho trude - Hoat ddng cua HS: + Khai bao diing va tra Idi su'dung ciing muc dich, - Woardo/vgrcJaHS:-I-Viet chuang trinh; + Giai bai dupe li khai bao (d vi du 1: Var a: array[0 9] toan md rdng (HS thudng gap nhifng liing tung of char; d v i du 2: Const n=100; VarB: array[1 n] giai); + Neu nhifng khd khan viet chuong trinh; - of real; ) *** Xac djnh eae tinh chat htru han, ciing kieu, ed chi Trong chuang trinh fWdTHPT cd rat nhieu khai so, theo yeu eau cua GV Cae hoat ddng se giiip HS bude dau hinh niem mdi va khd nhu: he dieu hanh, file, thu mue, dung dupe mdt kieu dir lieu mdi ed the xay dung de mang may tinh, giao thu'c, Internet (Idp 10); kieu dif giaiquyetmdtsd'baitoan phire tap hon; bude dau tie'p lieu, eau true re nhanh, lap, chuong trinh eon, ham, can vdi cac dac diem cua "mang mdt chieu" nhu htfu thii tuc (Idp 11); CO sd dif lieu, bang, khda, lien ket, ea sddif lieu phan tan (Idp 12), Tuy nhien, neu GV biet han phan [H, cung kieu dif lieu, tien hanh bai giang theo hudng tieh cue hda eac hoat b) Trinh bay khii niim -Hoatddngcua G l/.'-f Khuyen khich HS trinh bay ddng, chic chin viee day hpe eae khai niem TH se cd hieu biet eua minh ve khai niem "mang mdt chieu" ma hieu qua hon, tao niem hifng thii say me dHS hpc khdng can tham khao SGK; -i- Dieu ehinh, si/a chifa bdmdn.Q kjp thdi nhifng sai sdt eua HS trinh bay va hudng Tai lieu tham kh&o de'n mpt djnh nghTa chinh xac nhu SGK Hoang Chung Phuwng phap day hoc toan hoc & •Hoatddngcua HS: + Tt]nh bay ro rang each hieu truo'ng phd thdng trung hoc co' sd NXB Gido due, cua minh ve khai niem nay; + Trinh bay lai chinh xac H.1995 Ho SI Dam (chu biSn) Tin hoc 10 NXB Gido due, khainiem sau khlGV da nhan xetva su'a ehifa H 2006 c) Nhan dang khii niem H6 Si Dam (chO bien) Tinhoc 11 NXB Gidoduc, • Hoatddng cua GV: + Hudng din HS xac H 2006 djnh "mang mdt chieu" can nhan rd nhifng yeu td Le Vift Chung (chu bien) Bai tap Tin hpc 10 nao? -Xac djnh eac yeu td'dd thdng qua each "khai NXB Gido due Viet Nam, H 2010 bao" mang mdt chieu; -i- Dua eac vi du va phan vi Le Viet Chung (chii bien) Bai tap Tin hoc 11 du ve khai bao mang mdt chieu de HS tim "tinh NXB Gidoduc Viet Nam, H 2010 hpp le", - Hoatddng cua HS:+ Trinh bay dupe cae yeu to SUMMARY xac djnh (nhu: kieu cua cac phan ti}; each danh chi Teach Computer Science concepts in popular proso; ten mang; so lupng phan tu; -i- Phan biet cae yeu grams can bring about positive results if the teacher to, phan dd thdng qua lenh khai bao mang; knows better design and organize the activities of active teaching in the lesson itself Author of the ar+ Phat hien va chi nhifng sai lam cua eac khai bao ticle mentioned some specific examples to clarify this mang sai ma GVde nghj statement (kil-2/2014) Tap chi Gido dye so 327 53 ... dd lam rd hon tinh "hiiu han" cua khai niem nay; - Yeu cau HS kie''m tra lai vi du md dau de khang djnh "tinh hifu han, tinh xac djnh va tinh diing" ciia thuattoan; - Nhan manh tinh chat cung... thue hoac xac djnh mdt bude tie''p theo; - Xac djnh bai toan diing "vdi bat kin trii cam cho trudd" Cac hoatddng tren giiip HS nhan dang mpt thuat toan theo nhifng tinh chat ma nd dupe xac djnh va... khdi dpng may tinh; thuat toan tim nghiem PTB2; thuat toan ve dudng trung tn/e ciia doan thing AB eho tnrdc bing thude ke va eompa) va trinh bay; - Hoat ddng cd the'' td'' chii''c theo nhdm "tich