One of the most powerful defensive charms known to wizardkind, the Patronus can also be used as a messenger between wizards. As a pure, protective magical concentration of happiness and hope (the recollection of a single talisman memory is essential in its creation) it is the only spell effective against Dementors.
The wave visible above the level of the water is in fact only part of the wave; the wave extends down through the water column to the ocean floor as well. Waves start out in the deep, open ocean as relatively vertical in shape, Presnell said. As a wave travels toward the shore, though, the bottom part of the wave drags along the ocean floor. The upper part of the wave above the water line starts to move faster than the rest of the wave. As the ocean depth decreases closer to shore, the drag on the wave's bottom becomes stronger, and the upper part of the wave begins to tilt forward.
6. What causes waves on the ocean? Wind causes waves on the ocean. 7. What are the waves in the Earth called (Earthquake waves)? The waves in the Earth are called seismic waves. 8. Define frequency. Frequency is how fast a wave travels. 9. Define amplitude. Amplitude is the height of the wave. 10. What kind of wave travels by squeezing and spreading? (Give an example). Compression waves travel by squeezing and spreading. 11. What is it called when a wave bounces back and comes back to the source? It is called an echo or a reflection when a wave bounces back and comes back to the source. 12. What is sonar? Sonar is using sound waves to tell how far something is.