Which statement correctly explains refraction?
1. Light slows down as it passes from air to water, and this causes the object to appear curved
2. Light speeds up as it passes from air to water, causing an interruption in the light ray that creates the image
3. Light slows down as it passes through objects and causes them to appear to be disconnected
4. Light bends as it passes at an angle from one medium into another, causing the image to appear bent
