Cell Biology: Osmosis

Explore the movement of water molecules through a selectively permeable membrane as they respond to a concentration gradient. Determine how the rate of osmosis is related to the gradient.

Osmosis

Immediately see the difference in the rate of osmosis in direct response to increasing solution concentrations. Enlarge graph.

Lab Summary:

For this activity, students will use a Barometer to measure the change in pressure as water diffuses into a solution during the process of osmosis.

The diffusion of water will be measured by graphing the change in pressure in a closed system. In addition, the movement of water molecules in response to a concentration gradient will be examined by measuring the change in the rate of osmosis in response to a change in the concentration gradient.

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(student version)

Method:

Use a Barometer to measure the change in pressure as water diffuses into a solution during the process of osmosis.

Here's What You Need:

Probeware

Other Materials

  • Beaker, 1-L
  • Erlenmeyer Flask, 1-L
  • Graduated Cylinder, 100-mL
  • Y Tubing Connector
  • Mass, 50.0 g
  • Syringe
  • One-way Check Valve
  • Protective Gear
  • Dialysis Tubing, 4.5 cm wide, 15 cm long
  • Paper Towels
  • String, 30.0 cm
  • Water, Distilled, 2.0 L
  • Corn Syrup, 100.0 mL

Lab Manual:

This activity is included in Explorations in Biology (PS-2807) ,complete with Teacher Information pages, student instructions and handouts, and sample data for a total of 25 probeware-based labs. For your convenience, we offer bundles which provide the probeware necessary for the activities in the manual. For more information on these resources and bundles, click here.