What is a Plasma? Is it the 4th State of Matter? - [5]

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In this lesson, you will learn what a plasma is and why it is called the fourth state of matter. A plasma is simply a gas that has been given additional energy such that many electrons are removed from the outer valence shell of the gas atoms. The result is a combination of positively charged gas nuclei and negatively charged electrons, along with some remaining fraction of neutral gas atoms. Because of the charges present, a plasma can be thought of as a gas that conducts electricity. Plasmas are all around us - for example lightning is the breakdown of gas molecules into a plasma state. A plasma ball is a low pressure gas that has been ionized into a plasma. The aurora is when the solar wind gets trapped in the Earth's magnetic field and ionizes the gas molecules in the upper atmosphere. The light that we see from a plasma is simply photons that are emitted when an electron recombines with a positive ion yielding a neutral gas atom.