Crashing Down: How Breaking Waves Form

If a wave is defined by energy moving through a medium and interacting with the bottom, then any large body of water can have waves. If a lake is large enough for wind to build waves, then those waves will break when they reach the shore.

If the height of the wave (stored energy) drops as it collapses, and that water begins to move rapidly toward the sand, then the energy has shifted from potential to kinetic.

If the amplitude and height of a wave represent its energy, then a taller breaking wave will hit a swimmer with more force. If the break is large, then the energy transfer to the swimmer's body will be higher.

If the water becomes shallow, then the wave's orbital motion touches the seafloor. If the wave base touches the floor, then friction slows the bottom of the wave while the top continues at full speed, causing it to topple.

If a wave's energy reaches down to a depth of half its wavelength (the wave base), then it will only interact with the bottom when the water is shallower than that depth.

If the front of a wave slows down due to the shallow bottom but the back is still in deeper water moving fast, then the back catches up to the front. If they get closer together, then the wavelength shortens.

If friction slows the water at the bottom but not at the top, then the crest eventually "overtakes" the base. If the top moves further forward than the base can support, then the wave curls and breaks.

If the wave slows down and the wavelength shortens, then the energy is compressed into a smaller space. If the energy is compressed, then the wave is forced to grow taller and eventually becomes unstable.

If a wave only breaks when its height becomes too great for its wavelength or when it hits the bottom, then waves in the open, deep ocean rarely break unless the wind is extremely strong.

If a wave grows too tall relative to its length, then it cannot support its own weight. If the height-to-length ratio exceeds 1 to 7, then the wave will collapse.

If the seafloor rises very quickly, then the bottom of the wave is stopped abruptly. If the bottom stops fast while the top is still fast, then the wave crashes violently in a plunging motion.

If we categorize waves by how they collapse, then spilling (gentle), plunging (curling), and surging (sliding) are the three scientific types; flying and rolling are not standard terms.

If the horizontal space for a wave is reduced as it slows down, then the water must move vertically to compensate. If the water moves upward, then the wave height increases until it becomes top-heavy.

If the wave has collapsed and its energy is now pushing a thin sheet of water up the sand, then that specific movement of water is called the swash.

If the circular path of water particles is restricted by the solid ground at the bottom, then the circle is squashed. If the circle is squashed horizontally, then it becomes an elliptical or oval shape.

If the "break" is triggered by the relationship between the wave's size and the water's depth, then wavelength and depth are the primary factors. If the seafloor shape changes how fast the bottom slows, then it also matters.

If a wave crashes into the shore, then it releases a massive amount of kinetic energy. If that energy hits rocks and sand, then it physically wears them down and moves them.

If one part of a wave hits shallow water before the rest, then that part slows down first. If part of the wave is slow and the rest is fast, then the wave will bend or "refract" toward the shore.

If a wave breaks and continues to move toward the beach as a mix of foam and smaller waves, then that region is active. If that activity occurs between the break point and the dry sand, then it is the surf zone.

If energy cannot be destroyed, then it must change form. If a wave crashes, then it produces heat, sound, and physical movement of sand; however, it cannot create biological DNA.