Water moves from areas of high concentration to low concentration through a partially permeable membrane. When the concentration of water is higher on one side of the membrane, water molecules will move to the side with the lower concentration until equilibrium is reached. The diagrams show water molecules moving from left to right through the membrane as the concentration of water is higher on the left side.

1. Osmosis
• Water moves from high water
concentration to low water concentration
• Which way is the water moving left or right
through the partially permeable
membrane.
Key idea: Concentration
Movement happens when there is a difference between two sides.

2. •Which way is the water moving left or right?
Left Right
solute
water
1 Partially permeable membrane

3. •Which way is the water moving left or right?
Left Right
solute
water
2 Partially permeable membrane

4. •Which way is the water moving left or right?
Left Right
solute
water
3 Partially permeable membrane

5. •Which way is the water moving left or right?
Left Right
water
4 Partially permeable membrane

6. •Which way is the water moving left or right?
Left Right
solute
water
5 Partially permeable membrane

7. •Which way is the water moving left or right?
Left Right
solute
water
6 Partially permeable membrane

8. •Which way is the water moving left or right?
Left Right
solute
water
7 Partially permeable membrane

9. •Which way is the water moving left or right?
Left Right
solute
water
8 Partially permeable membrane

10. •Which way is the water moving left or right?
Left Right
water
9
Partially permeable membrane

11. •Which way is the water moving left or right?
Left Right
water
9
Partially permeable membrane

12. •Which way is the water moving left or right?
Left Right
solute
water
10 Partially permeable membrane