Surface Tension: Floating Duck
A two-photo sequence: A cotton wad floats in clear liquid inside a plexiglass tank, and a bottle labeled “Ivory” is next to the tank. In the second photo, the labeled bottle’s nozzle is tilted toward the liquid inside the tank, suds appear on the liquid’s surface, and the cotton is at the bottom of the tank.
Description: Cotton batting is wrapped around a ring stand clamp and held on with a rubber band. The cotton “duck” floats on water but sinks when detergent is added to lessen the surface tension. Pictures of actual soaped ducks are available.
Source: UW Card Catalog
Year: N/A Vol: N/A Page: N/A
Keywords: Surface tension, Duck, Cotton batting, Surfactant
Rating: 
Hazard: Low
- Use of inert substances
Effectiveness: Good
- Results are clearly observable
- Good connection from demo to course material
- Clear contrast between behavior of systems
- Moderate reliability
- Time to results is low
Difficulty: Medium
- Precise and delicate manipulations required
- Simple procedures
- High degree of equipment cleanliness required
Safety Precautions:
- Eye protection required
- Gloves required
Class: Liquids and Solids, Intermolecular Forces, Thermodynamics, Surfaces
Division: General, Physical Chemistry
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