4.2: Diffusion and Osmosis (Instructor Materials Preparation)

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Lab Materials

This is the prep for one section of 24 students.

Part 1: Brownian Motion

Students will do this part individually.

Materials	Quantity	Notes
Microscope slides	1 per student	Also used in Part 3
Coverslips	1 per student	Also used in Part 3
Water dropper bottles	1 per table
Carmine red powder	2 small watch glasses	On side counter

Part 2: Diffusion across a Semipermeable Membrane

Students will do this part in table teams.

Materials	Quantity	Notes
Beakers (400 mL)	2 per table
Wax pencil	1 per table
Dental floss or thread	1 per table
Dialysis tubing	2 per table
Phenolphthalein	1 per table	Dropper bottle—does not go down drain!
1 M NaOH (sodium hydroxide)	1 per table	Dropper bottle
Iodine (I2KI)	1 per table	Dropper bottle
1% starch solution	~10mL per table	On side counter
Pipette/pipettor setup for starch (10 ml)	2 per class	On side counter—specifically for starch
Pipette/pipettor set up	1–2 per table
Large waste bucket for starch	1–2 per class

Part 3: Osmosis and the Cell Membrane

Students will do this part individually.

Materials	Quantity	Notes
Elodea	2 bowls	On side counter
Forceps	2 pairs per bowl
5% NaCl solution	1 per table	Dropper bottle
Slidewash bowls	1–2 per room

Part 4: Experimental Design

Students will do this part in pairs.

Materials	Quantity	Notes
2% agar plates	2 per table	Use deep petri dishes for diffusion experiment
Clear plastic rulers	2 per table
Potassium permanganate	1 per table	Dropper bottle
Methylene blue	1 per table	Dropper bottle
Cork borers	2–3 sets	On side table

Contributors and Attributions

Biology Labs. Authored by: Wendy Riggs. Provided by: College of the Redwood. Located at: www.redwoods.edu. License: CC BY: Attribution