All matter can be found in three physical states: solid, liquid, or gas (although there is a fourth state, plasma ). A substance can change from one state to another (solid to liquid, liquid to gas, gas to solid, or vice versa) when exposed to changes in temperature and pressure.
These changes of state modify the volume of substances since they generally expand due to heating and contract due to cooling, but they do not entail changes at a chemical level, only physical ones.
The phenomena that occur when matter passes from a solid to a liquid state and vice versa are:
- Fusion. Process in which a substance changes its state from solid to liquid by increasing its temperature. This process occurs at a certain temperature called “melting point”, which is different for each substance. For example, the melting point of water is 0°C.
- Solidification. The process by which a substance changes its state from a liquid to a solid. This process happens when the pressure of the liquid substance is greatly increased. For example, water that is transformed into ice by compression (a very difficult procedure to achieve)
- Freezing. The process by which a substance changes from a liquid to a solid by lowering its temperature. The liquid freezes when its temperature drops below its freezing point (the temperature at which the liquid turns into a solid). For example, the water turns into ice cubes.
The difference between the states of aggregation of the matter is given by the proximity or distance that exists between the particles that make up that substance. Due to this proximity, the cohesion forces (attraction forces) between the particles will be greater or lesser and that, among other factors, will determine the state of aggregation of a given substance.
Matter in a liquid state (intermediate cohesion) has a definite volume but not a fixed shape; matter in the solid-state (greater cohesion) has a definite shape and the particles are together; Matter in the gaseous state (lower cohesion) expands freely and has no defined volume or shape.
Examples of liquids to solids Conversion
- Fruit juices – ice cream
- Ice water
- Milk – frozen milk
- Honey – crystallized honey
- Alcohol – solidified alcohol
- Mercury – solidified mercury
- Lava – volcanic stone
Examples of Solids to liquids
- Ice water
- sugar – caramel
- Glass – liquid glass
- Chocolate – melted chocolate
- Cheeses – melted cheese
- Butter – melted butter
- Candle – liquid paraffin
- Plastics – liquid plastics
- Metals – molten metals
- Fat – liquid fat
- liquids to gases
- Gases to solids
- solutions