Discovery of awesome X-rays! and Seeing inside the human body(kinda...

You know what they say "It's whats inside that matters." but how do we know whats inside? that's where X-rays come in handy. :P
Well now that you are reading, you probably know what we are going to talk about today. so let us begin.
:)

In 1895 Dr. W Roentgen conducted an experiment that involved passing electricity from a vacuum glass tube or Cathode tubes, in order to study cathode rays.

At that point in time scientists had discovered the cathode rays and further studies were in progress.

While studying Cathode rays Roentgen noticed that when he covered the cathode ray tube with a cardboard, no light was able to escape the cathode ray tube yet the fluorescent coated object was illuminated.

He realized that some invisible energy was being emitted by the object. He was surprised by the fact that this emitted energy was able to penetrate the paper sheet, and made the fluorescent object glow.

[Picture Usage Under Creative commons Credit]

He decided to put a thicker object in-between the object and the tube, the object was still illuminated but dimmer. He had discovered X-rays, in which 'X' Stands for Unknown.

And finally when he placed his hand in between, the x-rays were able to pass across his hand except for the skulls, This created a shadow on the fluorescent coated film.

He then demonstrated this to his wife Anna, created very first medical x-ray photograph of his wife's hand.(Picture Below) It was the very first time we were able to see (kinda) inside the human body without cutting in. :P

First medical X-ray by Wilhelm Röntgen of his wife Anna Bertha Ludwig's hand

[Usage Under Creative commons Credit]

So what exactly is an X-ray?

An X-ray is basically an Electromagnetic wave with a very short wavelength. (Click here to read my previous article about colors, spectrum, and wavelength.)

How short are we talking? very short. Xrays have wavelengths ranging from 10 nanometers to 0.01 nanometers.

[Usage Under Creative commons Credit]

When the electrons from the cathode part of the CRT hits the positive part of the metal, electrons either get slowed down by the atoms of the metal component and release energy or get shuffled through the atoms and release energy. This released energy is called X rays. which has a very short wavelength as I said earlier.

[Usage Under Creative commons Credit]

The X-ray photographs most people are familiar with are also produced using the same principle. the bones in the human body are made of calcium and are dense, hence the x-rays are unable to pass through, other tissues, however, has a low density and the x-ray penetrate right through them.
Hence the part that passes through bones gets blocked and the rest leaves the black mark on the film, generating a shadow of the bones and any hard material in the body.

Applications

The largest application of the X-rays is in medical science, as doctors are able to examine the inner parts of the body using X-ray Photographs from several angles.
These high energy electromagnetic radiation is also used for killing cancer cells, and shrinking tumors in radiotherapy.
Airport security people use them to scan the baggage of the travelers.
Xrays are also useful for evaluating the genuineness of the historic paintings.

References: I would also recommend watching this TED video on youtube (Click here), all images used in the post are used under CC0 license and Sources for images are cited below the images.