Infra/Ultrasound, Constructive/destructive Interference, Reflection, Refraction, &

Defraction

Sara Persson11/2/10Period 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.

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.

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.

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.