Electromagnetic Spectrum by https://padlet.com/abalmer537/nsvxhst6t2q3 A Summary en-us 2017-10-13 17:15:32 UTC 2023-05-26 16:04:07 UTC hello@padlet.com Introduction abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196908366 The visible spectrum of light is only a small part of a much larger spectrum containing many other wavelengths which we can't see. This spectrum is called the ELECTROMAGNETIC SPECTRUM!]]> 2017-10-13 17:17:36 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196908366 What does it look like? abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196909532 Though we can't physically see with our eyes the full scale of the spectrum, we know how it's wavelengths go from long to short, frequency low to high and energy low to high. (left to right)]]> 2017-10-13 17:19:57 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196909532 All Electromagnetic Waves have these properties: abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196913774 1- They are all transverse (electromagnetic waves)
2- They can all travel through a vacuum
3- They all travel at the same speed (3 x 108 m/s) in vacuum (and air)]]> 2017-10-13 17:30:43 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196913774 Electromagnetic waves have these properties in common with all types of waves: abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196914905 1- They all move energy from one place to another
2- They can be reflected and refracted
3- They all obey the wave equation (see below)]]> 2017-10-13 17:33:42 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196914905 Memory Aid abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196973668 To remember the order of the colours in the visible part of the spectrum you can use this memory aid:
Rats and                                    Radio
Mice                                           Micro
In                                             Infrared
Venice                                      Visible
Use                                    Ultra-violet
Xtra                                            X-rays
Gondolas                               Gamma]]> 2017-10-13 21:03:26 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196973668 Radio Waves abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196974622 They have the longest wavelength in the E-M spectrum.
Range: a few cm to several km
Uses: 
  • Transmission of TV programmes
  • Transmission of local radio programmes, police ad ambulance messages etc.

]]> 2017-10-13 21:10:42 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196974622 Microwaves abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196975165 Uses:
  • Fast food cooking - microwaves pass easily through food and are absorbed by water molecules.
  • Radar - Detects positions of ships, aircraft or missiles (travels faster than ultrasound)
  • Satellite communication eg GPS
Dangers: 
  • Since our bodies contain a large volume of water if exposed to  a large dose of microwaves, internal organs could be damaged as water in our cells is heated up.
]]> 2017-10-13 21:14:42 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196975165 Infrared Radiation abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196976142 All hot objects emit infra-red (I-R). The higher the temperature of an object, the more I-R it emits.
Uses:
  • Heating - Toaster, grills and cookers
  • Remote control for TV
  • Burglar alarms go off when they detect I-R
  • Night vision equipment uses I-R to detect the radiation given off by living creatures or engines
  • Astronomers use I-R photos to obtain information about the temperature of stars
Dangers: 
  • Too much I-R can damage cells and result in burns.
]]> 2017-10-13 21:21:44 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196976142 Visible Light abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196977164 Uses: 
  • Vision and photography 
  • Optical fibre communication systems 
  • Photosynthesis - occurs in green plants, where light energy is converted into chemical energy
 
]]> 2017-10-13 21:28:43 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196977164 Ultra-Violet Radiation abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196977416 Uses: 
  • To identify forgeries of bank notes
  • UV rays can be used for skin treatments in hospital 
  • UV rays kill bacteria _ UV lamps used in kitchens to sterilise crockery and in water chillers 
Dangers: 
  • Exposure to large amounts of UV radiation can damage eyes and cause skin cancer (minimised by using high SPF sunscreen and reducing time in sun)
]]> 2017-10-13 21:31:02 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196977416 X-Rays abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196977832 Uses:
  • Medical Diagnosis - X-ray photographs to identify broken bones 
  • Medial Therapy - The shortest wavelength X-rays are the most penetrating and they can be used to kill cancer cells 
Dangers: 
  • X-rays can damage cells and cause cancer 
]]> 2017-10-13 21:35:23 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196977832 Gamma Rays abalmer537 https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196978133 Uses: 
  • They kill living cells and so are used to kill cancerous growths - Radiotherapy 
  • Used in the sterilisation of medical equipment 
  • In the food industry, fresh fruit is treated with gamma rays to prolong its shelf life 
Dangers:
  • Gamma rays can cause cancer

]]> 2017-10-13 21:38:48 UTC https://padlet.com/abalmer537/nsvxhst6t2q3/wish/196978133