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,[.]
Trang 1REN 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$t h? thdng cdu hdi djnh hudng hdnh dpng
tu duy, gpi tit: cdu hdi djnh hudng tu duy Rdn luy§n
Trang 2NGHIEN Ctru & CFNG D U N G III
kT ndng giai bdi t|p ddi hdi phdi rdn luyen ed ba mat:
kT nang H thuyet, kT ndng trf tug vd kT ndng thue hanh
Rgn luy^n kT ndng gidi bdi tap phdi quan tam thyc
hi?n trong cdc gid hgc d trudng vd d nhd Cy thl:
• Trong qud trinh nghien cihi ly thuyet vdt li
Qk rdn luy^n kT ndng giai bai tdp cin ren luygn
nhQng kT nang, kT xdo bit ddu tir khi nghien cim Iy
thuylt mdi, Qud trinh nghign curu li thuylt mdi Id qud
trinh gidi quylt mdt he thdng bdi todn nhdn thirc Mdi
bude gidng dgy trong gid hpc khdng nhttng ygu cdu
SV ndm vQng kiln thdc, phuang phdp nghien cihi md
cdn phai ren luy?n nhihig kT nang tuong dng vdi ndi
dung cua boat ddng hpc tdp Trong gid hpc If thuyet,
nhtmg kl ndng ed the duge rdn luy$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)
Trang 3lti{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 dgy-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 ,
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