Fb-10 Surface Tension of Aqueous Solutions
Published: Friday 10 March 2006 - Updated: Tuesday 29 March 2011
To demonstrate that in general organic substances dissolved in water lower the surface tension.
- Overhead projector
- Petrie dish, water
- Razor blade
Click on pictures to enlarge.
If a piece of camphor is scraped into a dish full of water it will dart over the surface in a seemingly random manner.
Camphor is only slightly soluble in water. On an uneven piece of camphor, solution occurs more rapidly at a point P than where the surface is smooth. The strength of the camphor-water solution near P is greater than at any other point and hence the surface tension is least at P. THerefore the greater tensions on the other side pull the camphor away from P.