Trees convert light energy to chemical energy. when wood is burned, chemical energy becomes thermal energy. this heat can be used to run turbines (mechanical energy) that eventually create electrical energy. how would you model this transfer and conservation of energy?

When the ball is rising up, it gains kinetic energy. when the ball reaches the very top, it will have all potential energy, until it falls back down and gains it kinetic energy. finally when you catch the ball or it falls back down, it would have gained its potential energy back.