There are four forms of matter: Solid, Liquid, gas and Plasma and matter undergoes various state changes termed as melting, freezing, boiling, evaporation, condensation, sublimation and deposition.
<u>Explanation:</u>
Solids
A matter that have a definite shape because of its closely packed molecular structure; are known as Solids. It can be identified as they have a definite shape and cannot flow or float without external forces are applied.
Liquids
These have a an internal molecular structure with comparatively more spaces with one another. Liquids have a property to flow and change shape according to the container it is taken.
Gases
The internal molecular structure of gases has the widest range of space among one another and thus they have a floating property because of least density.
Plasma
A complete ionized gas which has equal amount of positively and negatively charged ions. The best example of plasma is a plasma-ball.
<u>Phase transformation among the four forms of matter</u>
<u>Melting</u>
A matter changing from a solid phase to liquid phase is known as melting. Ex: Ice into water
<u>Freezing</u>
A matter changing from liquid to solid is known as freezing.
<u>Boiling</u>
When the liquid is heated to its boiling point, this gets transformed into the state of gas where liquid's pressure equals to the external pressure.
<u>Evaporation</u>
Once the liquid reached the temperature range above the boiling point ad starts converting into vapours or gaseous state.
<u>Condensation</u>
When the gases changes from the gaseous phase to liquid phase, this is called condensation.
<u>Sublimation</u>
The change of solid into gas is called as sublimation.
<u>Deposition</u>
Deposition refers the thermodynamic process where phase transition takes place as the gas solidifies without passing through the liquid phase. An example: the process of converting water vapour from frozen air directly into ice without initially becoming a liquid.
is the emissivity of the object (in our problem, 
)
is the Stefan-Boltzmann constant
