In the first case: The reason for the appearance of the blue color in the filter is due to the ability of the methylene blue particles
to pass through the pores of the filter paper, in addition to the force of attraction (bonding) between the methylene blue
particles and the water molecules.The force of attraction between water molecules to each other is
stronger than the force of water molecules attracting the dye, which leads to the rush of the dye molecules to accumulate on the
surface of the charcoal particles, leaving the water molecules to pass through the clear filter paper free of the dye colored
methylene blue particles.The pores of the filter paper, so that the filter becomes blue again.