Senior Science Information Systems Part 2: Electromagnetic Spectrum

Electromagnetic Spectrum song video

Parts of a Wave

Types of Waves Electromagnetic Mechanical Waves that don’t need a medium (solid, liquid or gas particles) to travel Eg. Light Waves that need a medium (solid, liquid or gas particles) to travel Eg. Sound Video

Mechanical Waves Longitudinal Transverse The particles vibrate back and forth, parallel to the motion of a wave. The particles in the wave vibrate up and down.

Frequencies Sound waves are described in frequencies. Frequencies = pitch Low frequency = low pitch High frequency = high pitch Frequency is the number of waves that pass a point per second Frequency measured in Hertz

Properties of Electromagnetic Waves Summarise Pg 194-195 Properties of Electromagnetic Waves Intensity and distance Scattering and absorption Reflection and Refraction

Radio waves which includes: TV FM radio AM radio 1 Identify the types of waves in the electromagnetic spectrum currently used for communication systems as Visible light Infra-red Microwaves Radio waves which includes: TV FM radio AM radio 3 Identify communication technologies that use energies from the electromagnetic spectrum for communication purposes

Electromagnetic Waves video

The Electromagnetic Spectrum

Visible Light Visible light is created from multiple colours that each have their own wavelength.

Useful EMS Properties for communication technologies Speed of Light (3x108 m/s) in a vacuum. Its ability to travel in a straight line Its ability to be reflected

The electromagnetic Spectrum Summarise each of the types of waves and list communication technologies used with each. Pg 195-197 Radio waves Microwaves Infra-red Visible Light Ultraviolet X-Rays Gamma Rays

2 Compare the advantages and disadvantages of using microwaves and radio waves in communication technologies

Using Microwave and radio waves in communication technologies Advantages Disadvantages They can travel through air without requiring a medium such as wire Because the waves travel in a straight line and can be reflected, they need transmitter and repeater stations to get around corners and objects. They can broadcast to a huge audience over large distances. They don’t need people to be connected directly to one another or to the source of the information. Broadcasting over a wide area means that a lot of energy is wasted; the receiver of the signal must be tuned into the correct frequency. The frequency in transmission and reception of radio waves can be precisely controlled. The most effective frequency ranges in the EM spectrum are limited; so there is a lot of competition in those frequencies.