Hello students welcome to the new chapter called state of matter in this chapter we are going to learn some interesting facts about the word matter so in this module will learn introduction to state of matter. let me start with the word matter as we all know matter is anything that occupies the space possesses mass for example this chair and table or a glass of water or some balloon containing air so if I concentrate on this I come across with the new classification that matter is going to get classified into three different types that is called solid other one liquid and one more is called gases so along with these three we having some more state of matter like plasma boseeinstein condensate, fermionic condensate, quark condensate thought wave along with these three so let me concentrate on these three types called solid liquid and gases . if u look at these pictures you can come across with the some interesting facts that the faster picture is tightly bond nothing but solid second one is slightly distributed nothing but liquid last one is completely dispersed nothing but gases so by looking at this picture I think I can make out some interesting points with respect to this point number 1 if I concentrate on shape for solid this is perfect If I concentrate on liquid there is no perfect shape if I concentrate on gas and similar to the liquid there is no shape for gas also. If I concentrate on volume solid has got volume liquid has got volume but there is no volume for gases. I got there intermolecular force of attraction and on the word about that nothing but this particular word is very much essential for these two particular parameter for shape and volume so what is intermolecular force of attraction it is the attraction between two atoms if it is very much strong I will be having a solid shape but it is very ,very less then there is no shape and there is no volume so if I concentrate on intermolecular force of attraction it is very much strong in case of solids it is very weak in case of liquids and very week in case of gases so If I want a next point nothing but packing efficiency if I concentrate on packing solid are having closely packed structure if I concentrate on liquid is loosely packed if I concentrate on gases it is very loosely packed if I concentrate on next word called density we know the word density what is density it is nothing but mass by volume . if I concentrate on packing of this particular thing it is closely packed nothing but mass by volume is more in case of solids . so in case of liquid it is slightly less in case of gases it is very very less there for density is very high in case of for solids and it is very least in case of gases and is intermediate to solids and gases in case of liquids. So in the next point we are going to learn about the word called flow ability so the word of flow ability means that is the ability to flow which is maximum in case of gases and less in case of liquids least in case of solids. if I concentrate on compressibility it is nothing but ability to get compressed it is very high in case of gases and less in case of liquids which is very least in case of solids . so there are main two parameters or condition by which I think these particular matters or wearing those two are temperature and pressure . if you concentrate on solid I can interconvert this solid into liquid just by heating and I can interconvert this liquid into gas just by heating so there is interesting phenomena that I can convert ice into water this water into steam just by heating so temperature, so the temperature is the main criteria to convert solid into liquid, liquid into gas similarly I can convert gas into liquid, liquid into solid by applying pressure . so these two are very interesting condition by which I can convert a solid into liquid , liquid into gas now will concentrate on a new concept where and temperature will play a waiter roll to convert gas into liquid that means at the high temperature and low pressure gases will exist at the low temperature and high pressure liquid will exist there for transformation of liquid to gases can be done by wearing this two condition so we have to concentrate on high temperature low pressure of gases low temperature and high pressure for liquids .