NGHIEN crnj & I;NG DUNG
REN LUYEN Kl NANG GIAI BAI TAP VAT U M i ClTONG (HO SINH VIEN CAC NGANH KY THUAT TRONG DAY HOC PHAN NHIET HOC
PGS.TS. Nguyin Dinh ThlTAC, Trudng Dpi hpc Vinh ThS. Iran Ngoc Dung, Tritdng BH Trdn Beii NghTa, TP. Hd CM Minh
SUMMARY
Skill training of solving physical questions is one of important tasks in physics teaching for students. In this article, the results of study on skill training in order to solve physics questions and its applications in teaching Heal section (general physics program for technical students) are introduced.
Tir khda: Ky ndng, bdi tap vgt ly, ngdnh ky thudt dgy hgc phdn nhi$t di$n man bdi ngdy: 15/5/2014, ng^ duy ft ddng: 25/5/2014.
Rdn luydn kT ndng gidi bdi tdp Vdt li dai cuong Id mpt trong nhihig nhidm vy quan trpng eua dgy hpc Vdt li eho sinh vien (SV). Trong bdi bdo ndy, chiing tdi gidi thi|u ket qua nghien eiru vg ren luy^n ki ndng gidi bdi tap vat li cho SV vd ihig dung trong dgy hgc phin Nhiet hgc cho SV cde ngdnh ky thudt.
1. Ki ndng gidi bdi tap Vat If
KT nang gidi bai tap Vdt li Id kha ndng thue hien thuin thyc mdt chudi hanh dpng vgn dyng cdc kidn thue Vdt li, dua vdo gia thigt da cho dl giai quylt nhi?m vy trd Idi eau hdi theo ygu eiu cua bdi tap.
TVong mdt chudi hdnh dpng van dyng kign thdc ddi hdi t|p hgp nhtlng kT ndng, kT xdo vd nhQng thdi quen can thigt lign quan den vi$e thyc hi^n gidi bdi tdp.
Tap hpp nhtmg kT ndng, kT xdo vd nhdng thdi quen dy dugc rut ra td ehinh ban chit cua mdn Vat li vd nhtmg phuong phdp nghign cdu ciia nd. KT ndng giai bdi tdp cdn gin lien hang logt kT nang, kT xdo khae khdng gin lien rd r|t cua mdn Vgt li: kT xdo td chdc boat ddng hpc tap, kT xdo trinh bdy y nghT cua minh ed h6 thdng va logic, kl xdo sd dyng gido trinh, tdi lieu tham khdo, sach tra eunj,...
Viee vgn dung nhDng kien thde vao thyc tiln la su bign ddi. Id hdnh dgng tiep nhgn trong he thdng cua nhQng nguyen tie, qui tic hay thdi quen va nhung angdrit. Hdnh ddng tiep nhgn la mit xich quan trpng giiia kien thirc vd kT ndng. Hinh thanh kT ndng vd rgn luy^n kl ndng thyc hdnh giai bdi tap Vgt li cd tinh qui trinh, theo so dd sau:
Phdn tich kign ^1 Hdnh dpng I ^ KT ndng, thiifc ly thuygt " tigp nh$n | kT xdo
2. R^n iuyfn kl nSng giai bdi tgp V3t li Trong thyc tien dgy hge cho thay, nhigu SV ndm thd nhit lung tung khdng hodn thdnh dupe nhif m vu
gidi bai tap Vgt li dgi cuong. Cd the do nhigu nguyen nhdn khdch quan vd chu quan trong qud trinh day hpc Vat If d trudng phd thdng vd dai hpc, trong d6 cd nguyen nhdn ngudi hgc thilu kt ndng, nen din tdi thue trgng ndu trdn. Rdn luy^n kT ndng gidi bdi tap eho SV ed the bing hai con dudng: bing con dudng angdrit hda hodc bing con dudng dinh hudng hdnh ddng tu duy.
a. Ren luy$n ki ndng gidi bdi tdp Vdt li theo con dudng angdrrit hda la cdch xdy dyng mdt co sd djnh hudng chdt chg, trong qud trinh dd ngudi hgc hoSn todn thay duge cdch thye hi?n hdnh ddng, chia hdnh ddng thdnh nhQng giai dogn vd thye hi?n dung d3n nd. Nhiem vu quan trpng Id Idm cho SV nhdn thirc dugc chien luge tdng qudt gidi nhthig bdi tgp cdng logi (angdrit giai hay phuong phdp gidi). Chdng hgn trong phan Co hgc cd: chiln lupc tdng qudt giai bdi tap ddng lyc hgc vd chiln luge tdng qudt gidi cde bdi tap ddi hdi phdi vgn dyng cdc dinh ludt bdo todn....
Trong phin Nhift hpc: nhthig bdi tdp dinh lupng v|n dung phuong trinh trgng thdi eua khi li tudng, chiln lupc tdng qudt giai bdi tdp vl nguydn li thd nhat vd nguyen li thd hai cua nhidt dpng lyc hpe van dyng trong cdc ding qud trinh cua khi H tudng vd cdc qud trinh dign ra trong cdc dpng co nhi§t...
b. Ren liiy$n Id ndng gidi bdi tgp Vgt li theo con dudng dinh hudng Id rdn luy?n cho SV thyc hi§n hanh dpng cua minh theo nhOng kl hogch gidi todn, kl hogch dugc xdy dyng theo h? thdng hdnh ddng chi tigt vdi nhttng thao tdc ey thg. Bdng cdch cho SV hg thdng cdu hdi dya trgn kl hogch hdnh dpng cin thyc hi§n. Rdn luyen kT nang giai bdi t§p V^t 11 theo eon dudng dinh hudng, ddi hdi gido vien (GV) phdi chuin bi m$t h? thdng cdu hdi djnh hudng hdnh dpng tu duy, gpi tit: cdu hdi djnh hudng tu duy. Rdn luy§n
! • TAP CHi THI^ BI GIAO DgC- S6 106 - 6/2014
NGHIEN Ctru & CFNG D U N G
III
kT ndng giai bdi t|p ddi hdi phdi rdn luyen ed ba mat:
kT nang H thuyet, kT ndng trf tug vd kT ndng thue hanh.
Rgn luy^n kT ndng gidi bdi tap phdi quan tam thyc hi?n trong cdc gid hgc d trudng vd d nhd. Cy thl:
• Trong qud trinh nghien cihi ly thuyet vdt li Qk rdn luy^n kT ndng giai bai tdp cin ren luygn nhQng kT nang, kT xdo bit ddu tir khi nghien cim Iy thuylt mdi, Qud trinh nghign curu li thuylt mdi Id qud trinh gidi quylt mdt he thdng bdi todn nhdn thirc. Mdi bude gidng dgy trong gid hpc khdng nhttng ygu cdu SV ndm vQng kiln thdc, phuang phdp nghien cihi md cdn phai ren luy?n nhihig kT nang tuong dng vdi ndi dung cua boat ddng hpc tdp. Trong gid hpc If thuyet, nhtmg kl ndng ed the duge rdn luy$n nhu: kT ndng phdt bilu khdi ni$m, dmh lugt, qui tic, nguygn If; kT nang su dyng phuong phdp nghien cuu; kT ndng hodn thdnh hinh vg, so dd, dd thj; kT ndng dgc vd nhdn bilt dd thi, bilu dd;...
Vi dy 1. Vg dd thi ciia qud trinh ding nhi?t, dang dp, dang tich ciia khi li tudng trgn edc tryc tpa dd P,V;
P,T; V, T. So sdnh nhOng dd thi cua cdng mdt qud trinh vS trong nhthig trye tpa dg khde nhau.
Nghien cdu xong chu trinh Cdend vd djnh li Caend, ed thl dua ra nhttng bdi tgp djnh tinh - cdu hdi nhu;
VI dy 2. Hi^u suit ciia dgng eo nhiet theo chu trinh Carnot thu^n nghjch phy thupe vdo cde yeu td ndo. Hay ngu cdch tang hi§u suit ddng co nhi?t.
Vi dy 3. Vi sao hi^u suit li thuylt cua dOng co dtd thdng thudng vdo khodng 56%, nhung trong cdc dieu ki?n thyc te hi?u suit gidm ehi edn khodng 25%?
• Ty lyc gidi bdi lgp a nhd
D I thyc hi^n nhi§m vy rgn luy?n kT nang gidi bdi t§p d nhd cua SV ed hi?u qud, mpt trong nhOng dilu ki^n can thiet Id G V phai xdy dyng mpt h? thdng bdi t§p thda man nhOng tigu chi: h? thing bdi tgp phii kin phd kiln thdc, hudng den phd ndng lye tu duy rdng; cd nhtmg bdi tdp ddng vd bdi tdp md; phong phu cde dgng, logi bdi tgp; cd nhieu bdi tap ed npi dung ki thu§l lign quan din nghg nghigp tuong lai eiia SV. H$ thdng bdi tgp hip ddn, tgo nhu edu himg thii, ddi hdi lu duy sdng tgo, cd y nghTa quyet djnh tinh ty chu, tich eye giai bdi tgp d nhd cua SV. Nhd dd, kT ndng gidi bdi t§p dugc phdt trien.
• Trong cdc tiit thyc hdnh gidi bdi tgp a lop Sl lilt thyc hdnh gidi bdi t§p d Idp cua SV cd hgn.
Ldm sao dl rdn luy^n kT ndng giai bai tgp ciia SV ed chit lupng vd hi§u qud? Nhttng bdi tgp td chirc eho SV giai d Idp cd thl theo hai hudng dd Id: giai quylt
nhttng bdi tgp md sd ddng SV yeu cdu vd GV lua chpn mgt sd bdi tap trong hg thing bdi tap dd eho. Td chdc giai bai tdp theo con dudng dinh hudng tu duy.
Vi dy 4. Chu trinh Idm vi?e cua mpt dgng co di.^zen bdn ky duge bilu diln trgn hinh vg.
a) Nhdnh AB bigu diln qud trinh ngp khdng khi.
b) Nhdnh BC dng vdi qud trinh ngn dogn nhigt khdng khi tdi dp sudt p^.
c) 0 cudi qud trinh nen nhien lieu dugc phun vdo xylanh vd dupe ddt chdy trong khdng khi ndng, khi i6 pittdng ehuyin dpng sang phai, ddu tien Id ddng ip (nhdnh CD), sau dd Id dogn nhi?t (nhdnh DE).
d) Q cudi qud trinh dogn nhigt, van thodt md, dp suit gidm xudng p^^ (nhanh EB).
e) Nhdnh BA bilu diln qud trinh day khi ra khdi xylanh.
Tim hi?u suat eua dpng co diezen?
Cdu hdi dinh hudng lu duy:
1. Cdng do dpng eo diezen thye hien trong cd qud trinh tinh bdng cdng thirc nao? La edng md h^
sinh ra hay cdng md he nhdn vao?
2. Vilt phuong trinh tinh nhiet lugng tda ra khi ddt chdy nhien li?u vd phuang trinh nhi^t lupng nhd ra mdi trudng cua dpng eo?
3. Tinh cdng do he sinh ra? hifu suit ciia dpng
CO?
4. Bilu thue lien h? gida hg sd gian dang dp, he sd nen dogn nhi^t vd he sd gian dogn nhiet?
Giai. Cdng do ddng eo thyc hien trong ca qua trinh:
A ' - Q , - Q ' , (I)
Trong do Q, Id nhi?t lugng tda ra khi ddt chdy nhign li^u (nhdnh CD), Q, Id nhi?t lugng nhd ra (Xem tiep trang 43)
TAPCHiTHlfrBJGlAODgC-SdlO6-6/Z014 • 39
lti{HiHIH'!f\1ll-HII
4. Kit luSn
Diy mgnh ung dung cdng nghe thdng tin va truyln thdng trong day vd hpc ndi chung vd dgy va hpc cdc ndi dung vl sdn xuit hod hpc d trudng phd thdng ndi rieng Id rit quan trpng vd cin thilt; gdp phin ddi mdi phucmg phdp dgy vd hpe theo hudng hi?n dgi. B% vi?e irng dung ngay cdng cd hieu qua cin tiep tyc trien khai xdy dyng cdc md phdng vl ddy chuyin sdn xuit cung nhu cdc md phdng hod hpe khdc, ddng thdi dua cdc tdi lifu da xdy dyng lgn mgng Internet, kit hgp gitta phuang phdp ddo tgo truyen thdng vd ddo tgo qua mgng (E-Leaming).
Tdi lifu tham khdo
1. Dang Thi Oanh. Phgm Ngpe Bang. "Bude
ddu thir nghi$m xdy dung vd khai thdc cdc phai mim trong nghien cuu vd dgy hgc hda hgc". Ki yiu hdi thao khoa hgc. Trudng DHSPHN, 04/2003.
2. Dang Thi Oanh - Pham Ngpe Bang - Nguyin Trgng Thp. "Su dung Macromedia Flash xay dung cdc md phdng gdp phdn ndng cao chdt lugng dgy- hgc Hod hgc a trudng phd thdng". Ki ygu Hpi thao khoa hpc. Trudng DHSPHN, 04/2005.
3. Phung n l n Dat-Trin Thj Binh. "Hoa ki thudt dgi cuong". NXB DHSP Ha Ndi, 2004.
4. Bd Gido due vd Dao tgo. "Hod hgc 10, 11, /2". NXB Giao due, 2008.
5. Nguyen Trgng Thg. "Ifng dting tin hgc trong gidng dgy hod hgc". NXB Gido dye, 2002.
IIIIIIIIIIIIIIJIIIIIINIIMIIUIIIII IIIIIIIIIMIIJIJII IIIJIIIIIII
REN LUYEN Kl NANG GIAI BAl TAP VAT Ll... (r.^p.heo irang,,)
mdi trudng (dogn EB). Vi dogn CD dng vdi qud trinh ding dp, nen:
trong dd Tj vd Tj lin lupt Id nhi?t dd d ddu vd eulLciia qud trinh ddn ding dp. Vi qud trinh EB Id ding tich, ngn:
m ,
VV 3 (3)
trong dd Tj vd T^ lan lugt Id nhipt dd d diu vd cudi qud trinh dang tfch. Dodd, theo (1), edng do bg sinh ra bang:
A = - C , [ y ( T , - T , ) - ( T 3 - T , ) ] (4) hi§u suit:
Q, r(T,-T,)
Ldi giai din ddy ed the eoi nhu dd hodn thdnh.
Nhung bigu thue (5) ed thg bieu diln dudi dgng khde.
Cd thl bieu diln edc nhi?t dg T^, T, vd T^ qua T^
duge khdng?
Ddi vdi dudng ding dp CD, la cd: T^ / T, = V, / V, = p {p Id h§ s6 dan ding dp). Do dd T, = T^ / p . Ddi vdi qud trinh dogn nhi?t DE, ta cd: T, / T, = (V, / V , ) r - 1 = 5 , - 1
(S Id h§ sd ddn dogn nhi^t); do do T, = T^
/ S'' -'. Dli vdi qud trinh dogn nhi?t BC, ta cd:
= 6 ' (e Id h? sd ngn dogn nhipt).
do dd Tg = T| / 6''-' = Tj / peT-' Thay cdc gid trj T^, T|, Tj vdo bieu thdc (5) vd chd y ring p = e / S ; cudi cimg ta thu dugc hi?u suit cua ddng co:
n = > r ^
Y E - ' ( P - I ) 3. Ket luan
Ren luy^n kT nang gidi bai tap Vdt II dgi cuong cd >? nghTa thilt thye giup eho SV hilu sau nhQng kign thirc Vat li, phdt triln tu duy khoa hpc vd ndng lyc sdng tao trong vi?e van dung kign thue Vat li dng dyng vao thyc tien. Trong qud trinh rgn luyen kT nang gidi bai tap, edn dat duge mue tigu bdi dudng nang lye ty hpe, ty nghien edu cua SV. Bang cdc hinh thue vd phuong phap rgn luyen kT nang eung nhu phdi cd mdt h? thdng bdi tap cho SV trong qua trinh hpc tap nhu da ngu nhim thilt thye gdp phdn ddi mdi dgy hpc dai hpc.
Tdi lifu tham khao
1. Luong Duyen Binh. Vdt ty dai cuang Jap I;
Co - nhiet NXB Giao dye, 2008.
2. Phgm Minh Tuin. Nguyen ty dgng ca dot trong. NXBGD, 2002.
3. Nguyen Dinh Thudc. Phdt triin tuduycho hgc sinh trong dgy hgc bdi lgp Vgt li Dgi hpc Vinh, 2010.
4. David Halidy, Rober Resnick, Jearl Walker.
Ca sd Vgt li lap 3. NXB Gido dye.
TAP CHi THifTBI GIAO DUC-sd 106-6/2014 • 43
