Introduction to Matter Around Us
Every single thing in nature is composed of matter, but when you look at them, each object is different from the other. We cannot see the air around us, but a balloon can be filled with air and can be weighed. It occupies space and has mass. In order to move it, you need to apply some force. Hence, matter can be define as follows:
Anything that occupies space has mass and offers resistance is called matter.
It can be divided into different classes based on physical and chemical properties as shown in Figure 1.1.
When a solid is heated, its particles gain energy and begin to vibrate faster. In doing so, they occupy more space. Thus, solid expands. Eventually, vibrations become so strong that the particles leave their fixed positions and cause the solid to melt and change into liquid.
When a liquid is heated, the kinetic energy of the particles becomes so high that the intermolecular forces are very much reduced, hence, increasing the intermolecular distance between them.
The particles become free to move. In gases there is much vacant space between molecules. Hence, the gases diffuse easily. The pressure of a gas is due to bombardment of molecules on the wall of the container. The molecules bombard/collide with the walls of the container and cause the pressure of the gas. Solids are rigid and incompressible due to closest packing of constituent particles. Thus they do not tend to change their shape and size when an outside force is applied to them. Liquids and gases are fluids, i.e. they flow easily and change their shapes when an outside force acts upon them. Conversion from one form to another is called phase transition which is shown in Figure 1.2.
There are two more states of matter, namely
- Plasma and
- Boseâ€“Einstein condensate (BEC)