To answer this question let us take ice as an example.
Ice begins as water which is two parts hydrogen and one part oxygen. Unlike other similar substances though water is a liquid at room temperature while the other similar substances are gases at room temperature which makes water a very interesting subject. Water is a liquid at room temperature because the hydrogen atoms are attracted to the oxygen atoms that make up water. Because of this the hydrogen atoms "connect" to the oxygen atoms. This is called a hydrogen bond. This keeps the water from becoming a gas at room temperature. When the water is put on the stove to boil though we see "steam" coming from the pan we put it in. This is the gas form of water. Water becomes a gas when put over high temperature because the heat is giving the molecules more energy to move around causing the hydrogen bond to break making the liquid a gas.
If this is the case with the liquid form of water becoming a gas it is the exact opposite of it becoming a solid. Water turns into a solid when put in freezing temperature. It becomes a solid because the molecules are slowing done and soon they get so slow they hardly move at all. If kept in the freezing temperature then it will stay a solid. But when taken out slowly the molecules will start to get warm again causing the solid to become a liquid because the molecules are moving again and are connecting together to make the hydrogen bond I spoke of earlier.
I hope that has answered your question.
All solid can be liquified if the temperature is high enough.
it will condense and turn into liquids and if that cools too much it will turn to solid
When a liquid looses enough energy (heat), it turns into a solid.
Solids turn into liquids at their melting point.
Almost all solids will turn into liquid at some temperature.This process is called melting and the temperature at which the solid melts is its melting point.
All liquids can get 'frozen', it just means they turn into a solid state. This point is called the melting point. this refers equally to point where solids turn liquid and liquids turn solid. However, because you do not specify what type of oil (you could be talking about gasoline/petrol, or talking about oils in food, palm oil) i cannot tell you at what point it would freeze.
Solid doesn't spread.
Liquids have the form of the containers.
solid only vibrates and liquids are inter mediate between solid and gas.
Ice melting is probably the most common sight
Solid
Equal in volume? The heavier on would be the denser one. Equal in mass? They would weigh the same.