Caption: Because of refraction, light rays from the drinking straw are bend at the interface between water and air.

This makes the straw look bent at the interface too.

But everyone knows it's NOT bent since this is a common everyday-life phenomenon.

That "water" looks like blue guck.

Credit/Permission: © User:Bcrowell, 2005 (uploaded to Wikipedia by User:Liftarn, 2006) / Creative Commons CC BY-SA 3.0.
Image link: Wikipedia: File:Refraction-with-soda-straw.jpg.
Local file: local link: refraction_water.html.
File: Optics file: refraction_water.html.