When crystalline bodies are heated, the average kinetic energy of the particles of the substance increases. The forces of attraction between the particles are no longer able to keep them in their previous states. Having reached the melting point, the substance melts. The crystal is destroyed. Long-range order in crystals transforms into short-range order; matter transforms into a liquid state.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.