By - Aashish Loknath Panigrahi , Founder , VoPhysics Group
Microwave Oven and Microwave radiation
We use this device almost every single day and amazingly , it makes a lot of things much better . But have you ever thought how a microwave oven works and how this amazing device heats up your frozen pizza or chicken curry within minutes ?? Well , though building a microwave is way more complicated thing but you can definitely understand how it works and perhaps the next time when you will see microwaves , then you will be able to see it in a completely different way because then you will know how it works .
Welcome to first edition of VoPhysics's guide to technology and in this introductory phase we deal with one of the most important consumer electronic appliances in the history and we will try to learn the science behind it. Let's learn more about the microwave ovens and microwave radiations which runs it-
If you don't know what microwave radiation is then , we are here to help. Microwave is a type of electromagnetic radiation similar to the visible light due to which we can see beautiful colors. Now, What is the frequency range of microwave ?? And the answer is one meter to one millimeter and Where is this electromagnetic radiation used ?? It has tons of applications such as in your microwave oven or in the satellite communication.
Welcome to first edition of VoPhysics's guide to technology and in this introductory phase we deal with one of the most important consumer electronic appliances in the history and we will try to learn the science behind it. Let's learn more about the microwave ovens and microwave radiations which runs it-
If you don't know what microwave radiation is then , we are here to help. Microwave is a type of electromagnetic radiation similar to the visible light due to which we can see beautiful colors. Now, What is the frequency range of microwave ?? And the answer is one meter to one millimeter and Where is this electromagnetic radiation used ?? It has tons of applications such as in your microwave oven or in the satellite communication.
So , at the end Microwaves are just similar to that of visible spectrum but it has greater wavelength , hence smaller frequency and smaller energy.
Now as we have got a brief introduction to Microwave radiation , let's jump to understanding how the microwave oven works and what are it's advantages over conventional ovens .
There's an odd story of how the idea behind microwave oven was discovered and as many great inventions were invented during the world war 2 , so was microwave. The story of discovery of microwave goes back to Percey Spencer - A renowned physicist and inventor who was known for radar tube design. One day during his work he , was standing nearby a magnetron (which is the "thing" which generates microwave using cavity resonance- and we will discuss this in later articles) and he discovered that his chocolate candy bar got melted and so later he tested the magnetron with popcorns - which popped after a few minutes of exposure to microwaves and when he tested exposure of an egg to microwave , which later exploded on to the face of one of his co-workers (It might not have been soo funny for that co-worker).
Later Percy tested the effect of microwaves on metallic containers and he found out that the surface of such containers just lets the microwave radiation to bounce off along it's surface and can be used to contain it and hence he created the world's first microwave oven. Voila !!
Moving forward , let's understand what makes a microwave oven work ? And the answer is water molecules in the food. If you ever try to heat up an anhydrous material (something which doesn't contains any water molecules) within a microwave then it's temperature will not rise even by a single bit and the reason behind this is that it doesn't contains any water molecules and most of the things we eat do have water molecules and this tends to heat it during exposure to microwave. Now let's understand what makes water molecules soo special that it heats up during exposure to microwave.
Before beginning this section I would like to mention that rise in temperature occurs due to transfer in energy from one body to another and at a micro scale , the temperature of any body increases due to rise in motion of the atoms or molecules which makes up the body. The transfer of energy (which is heat) takes place through many ways such as - "Conduction" , "Radiation" and "convection" . In our case it's radiation .It's the same way by which you feel the sun's heat .
Now as we have got a brief introduction to Microwave radiation , let's jump to understanding how the microwave oven works and what are it's advantages over conventional ovens .
There's an odd story of how the idea behind microwave oven was discovered and as many great inventions were invented during the world war 2 , so was microwave. The story of discovery of microwave goes back to Percey Spencer - A renowned physicist and inventor who was known for radar tube design. One day during his work he , was standing nearby a magnetron (which is the "thing" which generates microwave using cavity resonance- and we will discuss this in later articles) and he discovered that his chocolate candy bar got melted and so later he tested the magnetron with popcorns - which popped after a few minutes of exposure to microwaves and when he tested exposure of an egg to microwave , which later exploded on to the face of one of his co-workers (It might not have been soo funny for that co-worker).
Later Percy tested the effect of microwaves on metallic containers and he found out that the surface of such containers just lets the microwave radiation to bounce off along it's surface and can be used to contain it and hence he created the world's first microwave oven. Voila !!
Moving forward , let's understand what makes a microwave oven work ? And the answer is water molecules in the food. If you ever try to heat up an anhydrous material (something which doesn't contains any water molecules) within a microwave then it's temperature will not rise even by a single bit and the reason behind this is that it doesn't contains any water molecules and most of the things we eat do have water molecules and this tends to heat it during exposure to microwave. Now let's understand what makes water molecules soo special that it heats up during exposure to microwave.
Before beginning this section I would like to mention that rise in temperature occurs due to transfer in energy from one body to another and at a micro scale , the temperature of any body increases due to rise in motion of the atoms or molecules which makes up the body. The transfer of energy (which is heat) takes place through many ways such as - "Conduction" , "Radiation" and "convection" . In our case it's radiation .It's the same way by which you feel the sun's heat .
So , Water Molecules are made up of one oxygen and two hydrogen atoms and the it has a dipole moment which essentially makes the molecule positive in one direction and negative in the other direction and this makes the molecules realign it's direction due to change in direction of electric field such as the one shown above and it causes motion of all the water molecules and this leads to more kinetic energy in the particles , which leads to more friction and thus more heat is generated. Perhaps , now you understand what makes a microwave oven work and why it needs water molecules in your food to heat it up.