The principle of wetting a basin of water with a towel is mainly based on the water absorption of the towel and the humidity change of the air. Towels are very absorbent. When the towel is immersed in water, it will quickly absorb water and increase the contact area between water and air in the basin. At the same temperature, the larger the surface area of liquid-gas phase, the faster the water changes from liquid to gas. With the evaporation of water, the humidity in the air will increase accordingly.