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.
Immediately see the difference in the rate of osmosis in direct response to increasing solution concentrations.
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.
Downloads
- Download Free Lab (PDF, 444 KB) (444 KB, .pdf)
(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
U.S. Educator prices shown.
Probeware
PASPORT Barometer/Low Pressure Sensor (PS-2113A) - $89
Measures atmospheric pressure changes and doubles as a low pressure sensor. For use with PASPORT Interfaces.
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
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
