Chocolate Bar In Microwave (Part-II)

Chocolate bar in Microwave (Part-II)

This diagram of the electromagnetic spectrum finds it place in all physics textbooks:

                                             Source

But the problem was I never got a physical sense of what that meant. It remained ‘yet another physics diagram’ for a really long time.

You see, unlike sound which can be neatly visualized using Schlieren imagery

                                       Source: NPR

or by other unconventional innovative means,

I had no idea how to even get started with electromagnetic waves.

Visualizing the microwave wavelength using a chocolate and an oven (although not my original idea) arose out of this need to understand microwaves a little better.  (Check out part-I of this post)*

But you can do more with some better but less delicious equipment.

You can get a couple of neon bulbs from an electronics shop and place them in a grid inside the microwave to view the standing wave while the microwave is in action

                                                    Source

This tells you how the heat is distributed at the bottom of the microwave oven. The lit bulbs are anti-nodes and unlit ones are the nodes .

You can also try (NOT recommended) to do this by placing a light bulb inside a cup of water instead of a neon bulbs.

                                  Better quality gif  - here              

As you can clearly see the bulb only lights up in the anti-node regions of the standing wave while the remaining regions are the nodes.

You can take this a step further if you have an infrared camera .

Mark Rober had this brilliant idea of using the infrared camera inside a microwave in order to ensure that food that is being microwaved is cooked evenly and completely on the inside.                          

                                              Source

And ElectroBOOM then took this to the next level by placing a cardboard box inside a microwave oven and looking at the heat map using a infrared camera.

                                    Source: ElectroBOOM                                            

That last gif my dear friends was the most satisfying physics animation that I had ever seen for a really long time ! It clearly illustrates the 3D standing wave heat map that is produced inside a microwave oven.

Although these aren’t the only ways to visualize the standing microwave pattern inside a microwave oven, but these are the ones that I was able to test them out with equipment that you can probably find at home or at school/university.

You are welcome to suggest more thought experiments, alternate methods or edits to this post, I would highly appreciate it!

Have a good one!

* Previous post: Chocolate bar in Microwave (Part-I)

** Why is wavelength of light important than its frequency ?