A friend claims that throwing a baseball up towards the school roof illustrates gravitational potential energy transforming into kinetic energy. What is wrong with your friend's statement?

The Statement is wrong because the reverse is the case as it is the  kinetic energy that is being transformed to gravitational potential energy.

Explanation:

As your friend throws  the baseball into the air the ball gains an initial velocity (u) and this makes the Kinetic energy to be equal to

Here  m is the mass of the baseball

       Now as this ball moves further upward the that velocity it gained reduce due to the gravitational force and this in turn reduces the kinetic energy of the ball and this kinetic energy lost is being converted to gravitational potential energy which is mathematically represented as (m×g×h)

as energy can not be destroyed but converted to a different form according to the first law of thermodynamics

Looking a the formula for gravitational potential energy we see that the higher the ball goes the grater the gravitational potential energy.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.