3.13 understand the detrimental effects of excessive exposure of the human body to electromagnetic waves and describe simple protective measures against them

Microwaves: internal heating of body tissue
Problem: Microwaves have a similar frequency to the vibrations of many molecules and so they can increase these vibrations, resulting in internal heating. In this way, microwaves can internally heat human body tissue.

Protective measure: microwaves ovens need to have shielding to prevent microwaves escaping and reaching the person using it (or anyone else around)


Infrared: skin burns
Problem: he infrared range of frequencies can make the surface molecules of substances vibrate, like microwaves, this results in a heating effect. However, infrared has a higher frequency, so it carries more energy than microwave radiation. IF human flesh is exposed to too much IR radiation, skin burns can result.

Protective measure: you can protect yourself using insulating materials to reduce the amount of IR reaching your skin.


Ultraviolet: damage to surface cells and blindness
Problem: UV radiation can damage surface cells and cause blindness. It is 'ionising', this means it carries enough energy to knock electrons off atoms. This can case cell mutations (which can lead to cancer)

Protective measure: Wear suncream with UV filters if out in the sun and stay out of strong sunlight


Gamma rays: cancer, mutation
Problem: Gamma rays have very high frequency and are ionising, they carry more energy than UV rays and therefore can penetrate the body much further. They can cause cell mutation or destruction, which leads to tissue damage and cancer.

Protective measure: Radioactive sources of gamma rays should be kept in lad-lined boxes when not in use. Should someone need to be exposed to gamma radiation(e.g. in chemotherapy) the exposure time should be kept as short as possible.

Source of most information: CGP