“Investigating Diffusion Through Living Membranes”

0.9% NaCl Filter paper – if needed 4 clean slides
10% NaCl Wooden applicator stick Cover-slips
dH2O 1 disposable mat Microscope
Sheep’s blood Disposable gloves
Place disposable matting on your table with the four slides, cover-slips as well as the
container of blood on top. Blood containers are dropper bottles and are NOT TO BE
USED IN ANY OTHER WAY – NO PIPETTES. Number each slide with a wax pencil.
Put a drop of blood on a slide and number it Slide #1.
Student 1 & Slide #1: With the wooden applicator stick, dip the end into the blood and place a
tiny drop onto 3 slides.
Student 2, 3 and 4: Take the slides and follow the directions for slide #2, #3 and #4.
THROW WOODEN APPLICATOR STICK IN BIOHAZARD SOLID WASTE CONTAINER
Slide#2

1. Place 1 drop of 0.9% NaCl with the drop of blood (use the filter paper to absorb
   excess liquid).
2. Add a cover-slip and use the filter paper to absorb excess liquid (if necessary).
3. Observe cells under 40X then 100X and then high power (400X).
4. Draw your observations.
   Slide#3
5. Place 1 drop of 10% NaCl solution onto the slide with the drop of blood (use the
   filter paper to absorb excess liquid).
6. Add a cover-slip and use the filter paper to absorb excess liquid (if necessary).
7. Observe cells under 40X then 100X and then high power (400X).
8. Draw your observations.
   Slide#4
9. Place 1 drop of dH2O onto the slide with the drop of blood (use the filter paper to
   absorb excess liquid).
10. Add a cover-slip and use the filter paper to absorb excess liquid (if necessary).
11. Observe cells under 40X then 100X and then high power (400X).
12. Draw your observations.
    Decide what osmotic process is taking place in each of the three experiments and title the
    diagrams: Sheep’s blood in an Isotonic solution, Sheep’s Blood in a Hypertonic solution
    or Sheep’s blood in a Hypotonic solution, respectively.
    CAUTION:
13. All the blood contaminated items stay on the mat. Upon completion of the
    experiment all disposable items (wooden applicator, filter-paper and the mat
    itself) will be put in the SOLID BIOHAZARD WASTE CONTAINER.
14. Place slides and cover-slips in the beaker containing bleach.

Sample Solution