SL Chemistry

Inter-molecular Forces

Hi Everyone!

     If you were asked how a gecko climbs walls, what would you say? The majority of people respond with answers such as “sticky feet”, “suction cups”, or “tiny little hooks.” In fact, none of these are accurate. The correct answer is inter-molecular forces. The inter-molecular forces in gecko feet are a type of Van der Waals’ force. These occur when a negative side of a molecule is attracted to a positive side of another. Gecko feet are covered in millions of rows of hairs with split ends. When the gecko pulls down against a wall, the hairs then lay flat. When this occurs, the surface area between the gecko foot and the wall increases considerably. This then activates the attraction between the molecules in the gecko’s foot and the wall. These forces allow geckos to climb walls, ceilings, trees, and even the roughest surfaces!

This is a gecko foot under a microscope!

- Giselle D.