1. Kiem tra
GV kidm tra ph&i chudn bi cua cac nhdm.
2. Trong tam
- HS lam dugc cac thf nghiem vd tinh hudng dpng va van dung If thuye't dd giai thich kdt qua. giai thich kdt qua.
3. Cach tien hanh
Hoqt dpng 1: Thao luan thi nghiem hudng ddng
Hoqt dpng cua GV vd HS - GV yeu dn:
+ Cac nhdm ttinh bay thi nghipm vd
hudng dpng.
Npi dung
~ Dai dien cac nhdm I^n lugt ttinh bay
Hoqt dpng cua GV vd HS
+ Nhan xet v^ cac thf nghiem.
- GV nhan xet danh gia vd: + Kei qua thi nghipm.
+ Van dung li thuyet dd giai thieh.
- GV dn luu y:
•f Neu cd nhdm nao k^t qua khdng dat yeu cau thi GV cho ldp thao luan vd cac didu kipn eua thf nghipm.
Npi dung
hudng sang, hudng nudc, hudng hod. - Cac nhdm lan lugt gidi thieu cac hien tugng thi nghipm cua nhdm dd ldp cCing quan sat ghi nhd.
~ Thao luan theo td vi ket qua thf nghipm.
- van dung li thuyei bai 23 de giai thich thf nghiem.
~ Dai dipn cac nhdm ttinh bay, ldp nhan xet.
Hoqt dpng 2: Hudng d^n bao cao thu hoach
1. Hudng dat
2. Hudng sang
Cach tie'n hanh
* Thi nghiem 1: - Mpt chau cay da
mgc rd, than, la. - Treo ngUgc chau cay de than quay xudng dat.
* Ttii nghiem 2: - Cho hat dau da nay
mam trong dng tru dai 2 cm.
- Treo n^m ngang. (adsbygoogle = window.adsbygoogle || []).push({});
* Thi nghiem 1: - Dat chau cay dSu
Ket qua
- Sau mpt thdi gian than quay len.
- Re va than mgc dai ra khoi dng tru.
- Re cong xudng dat va than quay len tren.
- Nggn cay se hudng
Giai thich - 6 chdi ciia than, sU phan bd auxin khdng dong deu, mat dudi nhieu hon mat tren, lam cho sU tang trudng d phia dudi than manh hon n§n than udn cong quay len tren. - 0 re va chdi nggn cd sU phan bd auxin khdng ddng deu.
- Su tang trudng khdng deu d mat tren va mat dudi.
3. Hudng nudc
4. Hudng hoa
Cach tid'n hanh da cd re, than, la vao day hpp.
- Hpp dugc khoet cac Id thOng d cac vj tri khac nhau.
* Thi nghiem 2:
Dat chau cay dau vao sat mpt nen den.
- Hat dau nay mam dat vao khay nho bang ludi thep dung mat cUa am.
- Treo khay nghieng 45°.
- Dat cay dau S giufa mpt chide hpp nhua trong sud't.
- Bon phan dam d mpt phia thfch hgp.
Ket qua ve chd c6 anh sang.
- Sau mpt tu^n chdi nggn cay vuon ra chd c6 anh sang.
- Re mgc xuyen qua lo thQng cfia khay -> quay xudng.
- Rd udn cong ve phia mat cua ^m.
- Hp r l mgc vuon vd
phfa c6 phan dam.
Gtai thich •
- Anh sang dugc chidu tCr mpt phia, ham lugng auxin phan bd khdng deu. Auxin phan bd it hdn d phfa dugc chieu sang, auxin d phia ddi dien Idn hon da thiic d^y sir phan bao v^ tang trudng ciia te bao -> cay mgc cong ve phfa anh sang.
- Rd cay c6 tfnh hudng dat dUdng ludn quay xudng va hudng nudc duong ludn tim ve phia CO ngudn nudc.
- R§ cay hudng vd phfa cac chcit khoang can thi^t cho sU sdng cOa te bao do la hudng hoa duong.
IV. DANH GIA
- GV nhan xet gid thuc hanh. - Danh gia kdt qua ciia cac nhdm. - Danh gia kdt qua ciia cac nhdm. (adsbygoogle = window.adsbygoogle || []).push({});
V. DAN DO
- GV yeu cau HS don ve sinh Idp hgc.