Lks Osmosis [PDF]

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LEMBAR KERJA SISWA A. Kelompok ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... B. JUDUL Pengamatan proses terjadinya difusi dan osmosis C. TEMPAT DAN WAKTU PRAKTIKUM ________________________________ ________________________________ D. TUJUAN Membandingkan transfor secara difusi dan osmosis E. RUMUSAN MASALAH Adakah perubahan ukuran pada kentang sebelum dan sesudah direndam? Bagaimanakah peristiwa yang terjadi pada sel-sel umbi kentang tersebut? Adakah perubahan warna pada air putih sebelum dan sesudah di tetesi tinta? Bagaimana peristiwa yang terjadi pada kondisi air putih yang telah ditetesi tinta? F. PENDAHULUAN Transportasi tumbuhan merupakan proses penganbilan dan pengeluaran zat-zat ke seluruh bagian tumbuhan. Proses transportasi itu berlangsung karena adanya proses imbibisi, difusi, osmosis, dan transport aktif. Difusi adalah peristiwa mengalirnya/berpindahnya suatu zat dalam pelarut dari bagian berkonsentrasi tinggi ke bagian yang berkonsentrasi rendah. Osmosis adalah perpindahan pelarut dari konsentrasi tinggi ke konsentrasi yang lebih rendah melalui membran semipermeable. G. ALAT DAN BAHAN Difusi 1. Gelas 2. Pipet tetes 3. Tinta Hitam 4. Air Mineral atau Aquadest Osmosis 1. Pisau 2. Tissue 3. Gelas 2 buah 4. Stopwatch



Kentang 6. Aquades/air putih 7. Larutan gula 5.



H. CARA KERJA Difusi 1. Siapkan gelas lalu isi dengan air mineral 2. teteskan kira-kira 10 tetes larutan tinta hitam kedalam gelas yang berisi air. 3. Amati penyebaran warna hitam tanpa pengadukan 4. Mencatat berapa lama waktu yang diperlukan dalam percobaan Osmosis 1. Bersihkan kentang mentah dari kulitnya. 2. Potong kentang dengan ukuran 2 × 1 cm sebanyak 2 potong. Usahakan potongan kentang tersebut memiliki berat yang sama. Saat mengupas kentang dan memotongnya upayakan jangan sampai terkena air atau cairan apa pun. 3. Siapkan larutan gula pada gelas A dan air pada gelas B 4. Masukkan potongan kentang secara bersamaan ke masing-masing gelas yang telah diberi tanda A (larutan gula) dan gelas B (air) 5. Biarkan potongan kentang tersebut terendam selama 20 menit. 6. Setelah 20 menit angkatlah kemudian simpan di atas tissue. Dan periksa keadaan kentang tersebut, kemudian ukur ulang kentang tersebut dan catat hasilnya. I.



HASIL PENGAMATAN Tabel pengamatan difusi Gelas



Warna Sebelum ditetesi



Sesudah ditetesi



Waktu yang Diperlukan untuk difusi



A



Tabel pengamatan osmosis



J.



Gelas



Larutan



A



Gula



B



air



Ukuran (cm x cm) Sebelum



Sesudah



Keadaan



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