The discovery of radiation is a long and complex story, with contributions from several scientists over a period of decades. Here's a simplified timeline:

Early Discoveries (1800s):

* 1801: William Herschel discovers infrared radiation while studying sunlight through a prism. He noticed that a thermometer placed just beyond the red end of the visible spectrum registered a higher temperature than expected.

* 1803: Johann Wilhelm Ritter discovers ultraviolet radiation, located just beyond the violet end of the visible spectrum, by observing its ability to darken silver chloride.

X-rays (1895):

* 1895: Wilhelm Conrad Röntgen accidentally discovers X-rays while experimenting with cathode ray tubes. He noticed that a fluorescent screen in his lab was glowing even when the tube was covered. He named the unknown rays "X-rays" because of their mysterious nature.

Radioactivity (1896):

* 1896: Henri Becquerel, inspired by Röntgen's discovery, was studying the fluorescence of uranium salts when he found that they emitted radiation, even in the absence of sunlight. This discovery marked the beginning of the study of radioactivity.

Further Discoveries and Developments (1900s):

* 1898: Pierre and Marie Curie discover polonium and radium, two new radioactive elements.

* 1900: Max Planck proposes the quantum theory of radiation, suggesting that energy is emitted and absorbed in discrete packets called quanta.

* 1905: Albert Einstein explains the photoelectric effect using the concept of light quanta (photons).

Today:

Radiation research has expanded significantly since these early discoveries, encompassing the study of various types of radiation, their properties, applications, and potential hazards.

It's important to note that the discovery of radiation was a gradual process, with several scientists building upon each other's work and contributing to our understanding of this fundamental force of nature.