SEEd - Grade 7
Strand 7.3: STRUCTURE AND FUNCTION OF LIFE Standard 7.3.2
1 class periods of 60 minutes each
Small Groups
Students will see how cells respond to changes in osmotic pressure by watching red onion cells shrink in salt water and by weighing potato slices before and after being soaking in salt water.
Students may have difficulty understanding that osmosis is the movement of water across a membrane. They will need explanations for why larger size particles do not pass through the small pores in the cell membrane. The potatoes should lose several grams of water to the salt solution and the red onion or elodea noticeably shrink inside their cell walls.
Scoring Guide:
1. Students follow directions and perform lab procedures……………..4
2. Students make observations and record data………………………..4
3. Students correctly answer analysis questions………………………..4
Use the correct answers document.
Lesson Design by Jordan School District Teachers and Staff.