Chemiluminescent Ammonia Fountain
Crystallization from Supersaturated Solutions of Sodium Acetate
Density and Miscibility of Liquids
Electrical Conductivity of Liquids and Solutions
Osmotic Pressure of a Sugar Solution
Vapor Pressure of Solutions: Raoult’s Law
A Visual Demonstration of Raoult’s Law
Water Softening — Hard and Soft Water With Soap
Clean Air With the Cottrell Precipitator
Color of Sunset: the Tyndall Effect
Getting Colder: Freezing Point Depression
Getting Hotter: Boiling Point Elevation by Nonvolatile Solutes
Salting Out: Making Liquids Immiscible
Volume Increase Upon Neutralization
Model of Osmotic Pressure
In the first photo, black beans and lentils are separated by a screen inside a plexiglass container with a lid. In the second photo, the beans and lentils are mixed on the left side of the screen, and the lentils are on the right side of the screen.
Description: Lentils and beans are used to represent molecules of two different sizes. The screen between them is small enough only to let the lentils through to the other side. Initially the “fluid” levels are equal. Shaking the container mixes the two “molecules” together. Soon, the “fluid” levels are different on the two sides of the screen.
Source: Journal of Chemical Education – Vol. 76
Year: 1999 Vol: 76 Page: 64
Keywords: Lentils, Fluid levels, Osmosis, Membrane
Rating: 
Hazard: Low
- Model or simulation
Effectiveness: Average
- Mild effects are seen by audience
- Good reliability
- Time to results is low
- Good connection from demo to course material
Difficulty: Low
- Simple manipulations for most to perform
- Simple procedures
Safety Precautions:
- Eye protection required
Class: Simulations, Properties of Solutions, Equilibrium of Chemical Systems, Osmosis
Division: General, Physical Chemistry
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