Question

Why does the bottom of a boat appear to be larger than the top boat in water?

Answer 1

Answer: Refraction

Step-by-step explanation:

Looking from above, an object under water appears larger than it does in air. It's not that the image the light gave our eyes is bigger. It's that the image is actually closer to our eyes, since the light is not passing straight down, but is instead bending relative to the water's surface. Light passing straight down would be perpendicular to the water's surface, like the vertical line on the letter T. A closer image looks bigger--the underwater object is magnified.

Answer 2

because air has an index of refraction of essentially 1 and water has an index of refraction of 1.33 the angle from which the rays of light reach your eyes is larger than the angle they would in air. This makes the angular size larger to your eyes which makes the object look larger relative to how they would look in air.