Matter In Our Surrounding

• Anything that occupies space and has mass is called Matter.
• The particles which make up matter are tiny particles called atoms or molecules that they cannot be seen with the naked eye.
• Pen, paper, clips, sand, air, ice, stars that twinkle, the sun that shines, the food we eat, bricks we use to make buildings, water in oceans and rivers, rocks that form mountains etc. are different forms of matter.
• Scientists classify matter in two ways:
  • Physical properties: Based on physical properties matter can be classified into three groups: Solids, liquids and Gases.
  • Chemical properties: Based on chemical properties matter can be classified into Elements, compounds and mixtures.

Characteristics of the Particles of Matter:

• Substances are made up of particles that exhibit some characteristics which can influence the state and properties (physical and chemical) of a substance.
• The following three characteristics are shown by particles of matter:
• PARTICLES HAVE SPACE BETWEEN THEM
• Every particle in a matter has some small voids in between.
• This characteristic determines the solubility of a substance in other substances.
• If a teaspoon of  sugar is put a glass of water and mixed properly the water level remains the same..
• This is because the particles of  sugar get into the inter-particle spaces between the water molecules.
• This proves the presence of voids between particles of a substance.
• But on adding more salt or sugar, it will dissolve until all the space between water particles gets filled.

PARTICLES ARE CONTINUOUSLY MOVING

• Particles of the matter exhibit continuous random movements due to their kinetic energy.
• For example, the spreading of ink in a beaker of glass, the smell coming from incense stick (agarbattis), etc. shows the particles of a substance move.
• Diffusion is the phenomenon in which the particles of two different types of matters intermix on their own.

• Diffusion of particles is faster when the temperature is increased because the kinetic energy of the particles increase, making them move more vigorously.

PARTICLES ATTRACT EACH OTHER

• There is an inter-particle force of attraction acting between the particles of every substance which needs to be overcome in order to break it.
• The strength of the force differs from one substance to another.
• The physical state of any matter is determined primarily by the inter-particle force of attraction and the kinetic energy of the particles.
• The force of attraction is maximum in the particles of solid matter and minimum in the particles of gaseous matter.