Waves (波浪) are beautiful to look at, but huge waves are greatly harmful to ships at sea, as well as houses and buildings near the seaside. What causes waves? Most waves are caused by winds' blowing over the surface of the water. The sun heats the earth, causing the air to rise and the winds to blow. The winds blow across the sea, pushing little waves into bigger and bigger ones.
The size of a wave is decided by how strong the wind is, how long it blows, and how large the body of the water is. In a smallbay, big waves will never build up. But at sea the wind can build up big, powerful waves.
It is believed that the height of a wave (in metres) will usually be no more than one-tenth of the wind's speed (in kilometres). In other words, when the wind is blowing at 120 kilometers an hour, most waves will be 12 meters high or less. Of course, some waves may came together to form big waves that are much higher.
