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Senior Science Society ~ Exploring Plasma as a 4th State of Matter

Each week in Senior Science Society (M15 during P5 lunch), our Year 12 students deliver “science presentations”.

This week we explored plasma as a 4th state of matter (presented by Sebastian T, Aaron N, & Aman A)

We’ve all been taught from a young age that there are three states of matter; solids, liquids and gas. However, there’s a fourth, more abundant and energetic state within our universe; plasma. Although it can be considered the 4th state of matter, its phase transition, such as that seen between the other three states, is not well-defined. 

The degree to which a gas must be ionised to be considered plasma depends on its context, making it difficult to provide a solid answer whether it is a 4th state of matter or not.

There are 2 types of plasma – hot and cold:

  • Hot plasma is fully ionised and is in a state of thermal equilibrium (no net transfer of thermal energy between them).

  • Cold plasma is partly ionised and its heavier ions and neutral particles remain near room temperature (300 Kelvin).

Did you know that we can create plasma from grapes? 

When 2 grapes are touching, they act as resonant cavities (a conducting structure that stores EM energy at specific frequencies). This causes the microwaves’ energy to concentrate into a small space where they touch, creating a strong EM field. This is able to rip electrons from K and Na atoms in the grapes, creating ions (ionisation). The free electrons and positive ions form plasma, pulsating at 120Hz, double the 60Hz frequency of the power supply.

Isabelle Raphael, Year 12