Diffusion and Osmosis (Instructor Materials Preparation)

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