WAVES AND SOUNDBy: Savannah Dotterman

Infrasound

Infrasound is a sound that is lower than 20hz.

This is the “normal” limit for human hearing. The study of this type of sound is called

infrasonic. Infrasound sometimes results naturally from

severe weather, surf, lee waves, avalanches, earthquakes, volcanoes, bolides, waterfalls, calving of icebergs, aurorae, lightning and upper-atmospheric lightning.

Ultrasound

Ultrasound is approximately 20 kilohertz. This is greater than the upper limit for

human hearing. The most well known use for ultrasound

is sonography to see the fetus in a pregnant woman.

Examples

ORGANISMS THAT USE INFRASOUND

ORGANISMS THAT USE ULTRASOUND

People use it to monitor earthquakes, charting rock, and petroleum formations below the earth

Animals perceive these waves and use them as an early warning for a natural disaster

People use it to see the fetus in a pregnant woman to make sure its healthy and developing ok

Bats use it for hunting prey

Used to find flaws in materials and to measure the thickness of objects

Constructive Interference

Constructive interference is when two waves combine to make a larger amplitude. To cause a constructive interference and not a destructive interference both of the waves have to have the same sign. They both either have to be negative or they both have to be positive.

Destructive Interference

Destructive interference is the opposite of constructive interference. When two waves combine to make a lower amplitude. It becomes lower because a negative tries to combine with a positive or a positive with a negative. Instead of the waves adding together they subtract from each other.

Examples

CONSTRUCTIVE INTERFERENCE

DESTRUCTIVE INTERFERENCE

The suns rays reflect off of items creating bright rays of different shades

When two of the same sound waves combine creating a louder sound

When two different radio signals combine causing static

The suns rays reflect off of items causing dark bands with no color

Reflection

The reflection of a wave is when a wave is going towards an object and bounces off.

Examples of this would be a stone in a pond that a wave can not pass so instead it hits it and bounces back.

Defraction

The defraction of a wave is when a wave has to travel around of through something.

An example of defraction would be a somebody trying to talk to another person through a wall.

Refraction

Refraction is when waves change speeds because they change mediums.

An example of that would be a wave slowing down because it goes from air to liquid, or a wave speeding up because it goes from solid to liquid.