EM waves

• all waves in the spectrum travel at 300000000m/s in a vacume
• a vacuum is a space with no particles
• all waves in the spectrum are transverse
• radiowaves are used for broadcasting and communications
• microwaves are used for cooking and satelite transmitions
• infra-red waves are used for heaters and night vision equipment
• visible light is used for photography and optical fibres
• ultra-violet waves are used for fluorescent lights
• x-ray waves are used for observing internal structures in medical applications
• gamma rays are used for sterilising food and medical equipment
• microwaves are dangerous as they cause internal heating of bodily tissues
• infra-red waves cause harmful skin burns
• ultra-violet waves are dangerous as they cause damage to surface cells (skin cancer) and blindness
• gamma rays are dangerous as they cause cancer and mutation
• ultraviolet, x-rays and gamma rays are ionising
• ionising waves remove electrons from atoms which causes mutations in cells = cancer