Happy new year, everyone!
It is good to be here in 2018 but it is better to have you here. It would be awesome if we would all be here in 2019.
A Little Bit of Background...
I was born in a little village that was at least two hours from the nearest city. Ironically, being born and later raised in this small village was by design and not by accident. My parents, especially my father wanted to be in full control of the influences his children were exposed to.
Consequently, most of the things I knew as a teenager were things my parents taught me. And oh, there way no television: my father gave it away. We had a black and white television that was only turned on at 9:00 pm for news. Good old days!
Well, the point is that I didn't know much about anything until I went to the university. Microwave ovens were one of those things I knew nothing about even though we had the traditional electric and gas powered oven in the house.
It is perhaps due to my limited knowledge about things that I'm curious about technology and how stuff works. So how exactly does a microwave oven warm food? Does using microwave ovens cause cancer? Is it harmful to use a microwave oven over an extended period of time?
What is a Microwave Oven?
A microwave oven is a type of oven that cooks and warms food items by blasting the food with high-powered radio wave.
Pixabay image: A modern kitchen showing a microwave oven
The wavelength of these radio waves are usually of the order of 12 cm. The microwave oven heats food through the means of a horribly complicated piece of equipment, the Magnetron or Cavity Magnetron
In the 1940's, an American scientist, Percy Spencer, while working on a microwave piece of equipment, he realised that the equipment made the chocolate in his pocket to melt. This started a series of development that ended in the modern day microwave oven.
Figures 1, 2, 3 and 4 show different aspects of the magnetron as was patented by Percy Spencer. In figure 3, the inner copper core (anode) and the outer copper core (cathode) are bound by North and South Pole of a magnet.
How Does the Magnetron Produce Microwaves?
Basically, the Magnetron produces short radio waves. It does this by resonating much like a flute except that the frequency at which it resonates is neither in the range that humans hear nor see. Below is an illustration of what goes on in the Magnetron.
First, there is the cathode which is shown in the figure as copper rod (1). When voltage is passed through it, it emits negatively charged electrons that move in a straight line (3) to the copper tube anode (2)
However, due to the presence of a powerful magnet underneath the cathode, producing a field that is parallel to the cathode, the straight line journey of the electrons are bent into a cyclical one (5), much like the figure below:
The holes carved into the anode, called cavities or resonant cavities has a similar effect on the electrons as the air blown into a flute or a bottle. When air is blown perpendicular to the mouth of a bottle, it resonates with a sound. Electrons passing through the edge of the cavities experience similar effect as they pass energy to the cavities making them resonate at the frequency of the microwave radiation it produces. Of course, in this case, the waves are invisible.
The microwave radiation is collected by some form of waveguide (7) and used in a radar system or in this case, microwave oven. The waveguide directs the radiation to the food compartment of the microwave oven where the food sits on a rotating turntable in order to be cooked evenly.
So How Does a Microwave Cook Food?
Well, when the microwave pass through the food items, it vibrates the molecules of the food passing energy to them and heating them up. Because the food items are rotating, and the radiation passes through, heating is more uniform. The only risk is overheating and loss of nutrients in the food. It also turns out that the vibration is more effective in fat, sugar and protein which are basically the main components of food.
Is Microwave Oven Dangerous to You?
It is easy to fall into the temptation of thinking that once it is called radiation, then it must be harmful. But the wavelength of the radio waves involved in a microwave oven are much different from that of x-ray and gamma rays. In order to put this in perspective, examine the image below.
As can be seen from the figure above, the frequency of the microwave radiation is just between that of radio and the visible spectrum. So, apart from burning your food if overexposed, microwave oven presents no known health dangers.
I hope this has been informative for you. I'd like to thank you for visiting my blog.
It's your boy Kels,
@churchboy
