Infrasound Waves Infrasound is sound that is lower in frequency than 20 Hz (Hertz) or cycles per second, the "normal" limit of human hearing. Five organisms that use infrasound: Whales Elephants Rhinoceros Okapi Alligator These animals use infrasound to communicate over distances—up to hundreds of miles.

Ultrasound Waves Ultrasound is cyclic sound pressure with a frequency greater then the upper limit of human hearing. It is approximately 20 kilohertz (20,000 hertz). Some animals use ultrasounds for everyday lives. Examples: Bats Whales Dolphins Horses Cattle These sound help many animals. They also have some downfalls because for dogs it can be a really irritating sound for them. Many animals use this sound for hunting like bats to locate there prey.

Constructive Interferences If two of the components are of the same frequency and phase ,the wave amplitudes are reinforced, producing constructive interference. They vibrate at the same time and are maximum at the same time. Examples: Rogue waves in the ocean. Two people talking.

Destructive Interferences Destructive interferences is when 2 different waves are heading in the same direction and end up destroying each other. This happens because the vibrations hare at different times and maximum is different. Examples: The interference with the crest and the trough.

Reflection When the waves from an object bounce off an object and bounce inward. Example: jumping into a pool and the waves hitting the side and bouncing back in.

Refraction The change of direction due to the speed of the wave. The wave tends to move more in an other direction when the speed increases. Example: When water is shallow waves begin changing direction.

Defraction When a wave that is blocked by an object moves from one direction to another to go around or through and opening of the object. Example: covering your mouth and the sound waves going around.