1. Infra/Ultrasound, Constructive/destructive Interference, Reflection, Refraction, & Defraction Sara Persson 11/2/10 Period 2

2. Infrasound & Ultrasound There are many organisms that use either infrasound or ultrasound. Organisms that use ultrasound: Bats, Rodents, Insects, Dolphins, Whales, etc. Organisms that use infrasound: Elephants, Rhinoceros, Giraffes, Okapis, Alligators, etc.

3. About the Infra/ultrasound Organisms Bats use ultrasound to communicate in the dark. There are claims that ultrasound can frighten away rodents and insects, but there is no scientific evidence behind it. African Elephants use infrasound for long distance communication. These communications can be for coordinating herds, or for finding mates.

4. Constructive & Destructive Interference Constructive Interference: When two waves with the same amplitudes combine to create a more intense wave. Destructive Interference: When two waves are out of phase, and therefore cancel each other out. Examples for both Constructive and Destructive Interference can be within anything that forms waves: Water, sound, and light.

5. Reflection, Refraction, & Defraction Reflection: When a wave hits a boundary, bounces off, and begins moving in the opposite direction of that boundary. – Everyday Life Example: Waves bouncing from the edge of a pool. Refraction: When a wave bends and/or turns as it passes through different states of matter. – Everyday Life Example : Sound coming from another room. Defraction: When a wave scatters to move around an object in the way of it’s travel. – Everyday Life Example: Holding your hand in front of your mouth.