Some objects emit or absorb certain electromagnetic wavelengths, thereby, emitting or absorbing its own particular electromagnetic wavelength.
The frequency of the wavelength makes it specific and only absorbed or emitted by that object.
On one end of the electromagnetic spectrum we have short, or “low”, more frequent gamma rays that can penetrate cells and atoms. Extending down to the other end of the electromagnetic spectrum, we have longer, or “high”, radio frequencies, used to cover a greater area.
Discussion Question:
Look at this picture:
(Image retrieved from: http://static.howstuffworks.com/gif/cell-phone-radiation-spectru.gif)
Gamma rays, ultraviolet rays, visible light and microwaves are all part of the electromagnetic spectrum.
Mobile phones emit and receive wavelength frequencies in the microwave-radio spectrum. Mobile phones, microwaves, and sometimes even radios, collect media attention on the topic of health issues relating to the dangers of using electromagnetic receiving techonology.
Looking at the position of the frequencies a mobile phone receives, do you propose a mobile phones emit harmful radiation, as the media depicts? Keep in mind that visible rays are harmless as we are exposed to it 24 hours, 7 days a week since the dawn of time, and the visible light spectrum is closer to the harmful ionizing radiation of x-rays and gamma rays.
Flame Colours 
Comments on: "Electromagnetic Spectrum" (2)
I’m not sure if this has already been posted, but as I cant see it I’m going to repost. The image would suggest that the frequencies of the visible light is closer to the frequencies that produce the type of radiation that can be potential harmful to humans as opposed to mobile phone frequencies that are longer than visible light and are more closer radio waves as they are part of the microwave section of the electromagnetic spectrum. According to the Better Health Channel website as of April 2010 “international research has found no conclusive evidence that mobile phones are damaging to health in the short or long term, including any link to cancer”.
– Christina
Thank you Christina,that is the conclusion what I was hoping for.
As Christina has spotted, the visible light spectrum is closer to those harmful radiations, such as gamma and x rays.
Great job 🙂
So then how does this relate to our topic of visible light and flame colours?
We are just trying to give you all some background of the concept of how we see the flame colours produced by the individual electron configuration of an atom, and build on your knowledge of the electromagnetic spectrum, as we will be covering other aspects of the electromagnetic spectrum in other areas of HSC Chemistry.