Diffusion

1
Diffusion Osmosis with an Egg Cell
2
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

3
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

4
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

5
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

6
Isotonic

• Isotonic solution Solute concentration inside
  and outside the cell are equal

7
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

8
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

9
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

10
Lab Notebook
Qualitative Observations Qualitative Observations
  Before Placement in Solution Changes in Appearance/Characteristics after Placed in Solution
Vinegar    
Distilled Water    
Salt (NaCl)    
Sucrose    
     
Mass of the Eggs Mass of the Eggs Mass of the Eggs Mass of the Eggs
Solutions Initial Mass (grams) Final Mass (grams) Change in Mass (grams)
Distilled Water      
Salt (NaCl)      
Sucrose      
       
Volume of Solution Volume of Solution Volume of Solution Volume of Solution
  Initial Volume amount placed in the cup (mL) Final Volume amount present AFTER the egg was removed (mL) Change in Volume (mL)
Distilled Water      
Salt (NaCl)      
Sucrose      
       
Egg Measurement Egg Measurement Egg Measurement Egg Measurement
Solutions Initial Circumference (cm) Final Circumference (cm) Change in Size (cm)
Distilled Water      
Sale (NaCl)      
Sucrose