Question

Why is a bottom of a pond is cooler than the top during a hot summer day?

Answer 1

B/s water the bad conductor of heat due to which heat which is produced on the surface doesn't transmit to the bottom due to which the water present at the bottom of the pond  remains cool as compared to the surface

Answer 2

The sun heats the surface of the water of the pond, and as warm water has a lesser density, it floats on the cold water which sinks to the bottom of the pond. And also, water absorbs heat very slowly, so it takes times to heat up the bottom, which is why the bottom feels cooler than the surface.