Lab #4 Osmosis (pg S59)


Lab #4 Osmosis

(pg S59)

• Katherine wants to investigate if she adds fertilizer before she waters her plants or after watering?

• 1. Will water move into or out of a plant cell if the cell has higher water potential than the surrounding environment?

• 2. What would happen if you applied saltwater to

• the root of a plant?

• 3. If you place fertilizer before you water the grass,

• will that change the movement of water into

• the plant?

Lab #4 Osmosis

• Design an experiment to identify the Molar (M) concentrations of the sucrose solutions and use the solutions to determine the water potential of the plant tissue.

• *Use different potatoes (potatoes, yams, sweet potatoes)

• *Unknown M concentration

• *Different sizes of cubes

– (surface area)

Lab #4 Osmosis

• Procedures:

• 1. Cut four (4) potato cubes (DO NOT include skin).

• 2. Mass your four cubes (1 set) for Initial weight.

• 3. Place cubes in cups with sucrose solution molarity. Label cups

• 4. Make observations and place cups in order of Molarity.

• 5. Let it stand overnight (24hrs)

• 6. Mass your four cubes for Final weight. Calculate % change in mass.

• 7. Construct a Graph with class data


• 1. How can you measure the plant pieces to determine the rate of diffusion?

• 2. How would you calculate the water potential in the cells?

• 3. How can you determine which color of water is which M sucrose concentration?

• 4. Which solution had a water potential equal to that of the plant cells? how do you know?

• 5. What would your results be if the potato were placed in a dry area for several days before your experiment?

• 6. When potatoes are in the ground, do they swell with water when it rains?