# Science Chapter3 Lesson1

## Vocabulary

Electromagnetic wave- a transverse wave that involves the transfer of electric and magnetic waves.

Electromagnetic Radiation- the energy transferred through space by electromagnetic waves.

Polarized Light- light that has been filtered so that all of its waves are parallel to each other.

Photoelectric effect- the ejection of electrons from a substance when light is shined on it.

Photon- A tiny particle or packet of light energy.

Electromagnetic waves.flv

## What Makes Up an Electromagnetic Wave

Radio waves, microwaves, Infrared waves, visible light, ultraviolet rays, and tiny amounts of X-rays and gamma rays are all electromagnetic waves. Most of these waves are invisible our hearing and sight. Electromagnetic waves don't require mediums, unlike mechanical waves, to travel through.

## Characteristics of electromagnetic wave

Electromagnetic waves are transverse waves that transfers electric and magnetic waves. Key: An electromagnetic wave is made up of vibrating electric and magnetic fields that move through space or some medium at the speed of light. Electromagnetic waves begin with movement produced by charged particles. When these particles change speed and direction, both a magnetic and electric field is made. This process repeats and the two fields stay at 90 degree angles of each other. These waves travel as fast as the speed of light, 186411 miles per hour.

## Energy

Since electromagnetic waves don't require a medium they can transfer energy through a empty space. When energy transfers through matter or space as an electromagnetic wave it is called electromagnetic radiation.
electromagnetic wave

## what models explain how electromagnetic waves behave

Key: Two different models are needed to explain the behavior of electromagnetic waves. A wave model best explains many of the behaviors, but a particle model best explains others. Light is considered an electromagnetic wave because it has the properties of a wave, but can also act as a stream of particles.

## wave model of light

A wave model describes how light propagates much like how ocean waves move through the water.The Wave Model accounts for the performance and distortion of light when interacting with objects and openings that have sizes similar to the wavelength of light. Waves properties are shown when light moves through polarized filter. Light has waves that vibrate in every direction. Polarizing filters act as a fence with slits facing the same direction. This stops some waves from passing through, and the waves that do pass are called polarized light.

## particle model of light

Light can behave as a stream of particles. When a high frequency beam of light shines on some types of metals, it causes tiny particles called electrons to move. Sometimes light particles can even knock these electrons off the metal, this is called the photoelectric effect. This is pretty much explained by thinking about a stream of particles of energy knocking electrons off a surface. Each of these packets of energy are called photons. Without the photons, or strong photons, the photoelectric effect wouldn't work. this is because strong photons are required to knock the electrons off their surface.
Photoelectric Effect