how come insects can walk on water?

Question: how come insects can walk on water?
- Keywords:
  insect,
  walk
Asked by kezzy to David, Helen, Ian, rhysphillips, Sarah on 22 Jun 2011.
- David Corne answered on 21 Jun 2011:
  
  liquids have “surface tension”, which acts like a skin on the surface — insects are so light that they don’t break it.
- Ian van der Linde answered on 21 Jun 2011:
  
  Insects are very light and their bodies don’t get saturated with water and become heavy because they don’t have furr or other surface materials that could get waterlogged.
- Helen Fletcher answered on 22 Jun 2011:
  
  As David says, insects are small enough that their weight can be supported purely by surface tension, which is formed by weak forces that hold water molecules together. The insects also have some adaptations that help, like tiny hairs on their legs and feet that can trap pockets of air and stop the water soaking in. These can also be coated in wax to repel the water. Did you know that some larger animals can ‘walk on water’ too? Like some lizards and water birds. Like you, these are too big for surface tension to support their weight, so they do it by going too fast to sink! As they bring a foot down, air forms around it, which if they’re quick enough, they can use to push off against. Otherwise the air pocket closes and it gets dragged down into the water. I wouldn’t recommend trying this in your swimming lesson though.
- Rhys Phillips answered on 22 Jun 2011:
  
  Because they are very light!

Question: how come insects can walk on water?

Comments