Diffusion & Osmosis
with an Egg Cell
Vocabulary
•
Diffusion: The movement of molecules in a solution
from areas of high concentration to one of lower
concentration
Ex. Glass of water and colored dye
•
Osmosis: The diffusion of water molecules through a
selectively permeable membrane from an area of
higher water concentration to an area of lower water
concentration
Ex. Distilled water and salt water
•
Selectively Permeable Membrane: A membrane that
allows only certain materials to pass through it by
diffusion
Vocabulary
• Solute: Dissolved in another substance known
as a solvent
Ex. Salt
• Solvent: A liquid that dissolves a solute
resulting in a solution
• Ex. Water
• Solution: A mixture of solutes and a solvent
• Ex: Salt Water
Hypertonic
• Hypertonic solution: Greater
concentration of solutes (ex. salts)
outside the cell than inside the cell.
Osmosis causes water to move out of the
cell causing the cell to shrink
Hypotonic
• Hypotonic solution: Greater
concentration of solutes inside the cell
than outside the cell. Osmosis causes
water to move into the cell causing the
cell to expand
Isotonic
• Isotonic solution: Solute concentration
inside and outside the cell are equal
LAB – Day 1
• Removing the Shell on your Eggs
– Place 4 eggs in vinegar and allow to sit over
the weekend
– Read through methods for next week, make
predictions and answer questions, and decide
upon a fourth solution
LAB – Day 2
• Observations & Measurements
– Qualitative Observations
– Initial Circumference of Eggs (cm)
– Initial Mass of Eggs (grams)
• Place in One of Four Solutions
– Record volume of each solution
– Gently place one egg in each
solution and allow to sit overnight
LAB – Day 3
• Observations & Measurements
–
–
–
–
Qualitative Observations
Final Circumference of Eggs (cm)
Final Mass of Eggs (grams)
Final Volume of Solutions (mL)
• Wrap-up
– Dispose of eggs and clean plastic
cups
– Answer questions in lab notebook
Lab Notebook
Qualitative Observations
Before Placement in
Solution
Changes in
Appearance/Characteristics
after Placed in Solution
Mass of the Eggs
Solutions
Vinegar
Distilled
Water
Distilled
Water
Salt (NaCl)
Salt (NaCl)
Sucrose
Initial Mass
(grams)
Final Mass
(grams)
Change in
Mass (grams)
Sucrose
Volume of Solution
Egg Measurement
Solutions
Initial
Circumference
(cm)
Final
Circumference
(cm)
Initial Volume:
amount placed
in the cup (mL)
Change in Size
(cm)
Distilled
Water
Distilled
Water
Sale (NaCl)
Salt (NaCl)
Sucrose
Sucrose
Final Volume:
amount present
AFTER the egg was
removed (mL)
Change in
Volume
(mL)