In Class 9 Chemistry (Matter in Our Surroundings), we learn that everything around us—solid, liquid, or gas—is made up of tiny, invisible pieces called particles (atoms or molecules). These particles exhibit three fundamental physical characteristics.
The continuous, random, zig-zag motion of tiny particles suspended in a fluid (like dust dancing in a beam of sunlight) is called Brownian Motion, named after the botanist Robert Brown who first observed pollen grains jiggling in water.
Even if a solid object looks completely solid and unbroken to our eyes, at the microscopic level, there are empty spaces between its particles.
Proof Activity: When you dissolve a spoon of sugar in a glass of water, the water level does not rise. This happens because the tiny sugar particles break apart and hide in the empty spaces existing between the water particles.
Particles are never completely still; they are always vibrating, rotating, or moving around. Because they move, they possess Kinetic Energy.
Temperature Effect: If you heat a substance, you give it thermal energy. This turns into kinetic energy, making the particles move faster. Proof Activity: The smell of hot cooked food reaches you from meters away because the hot aroma gas particles are moving very fast and mixing (diffusing) with the air particles rapidly.
There is an invisible force of attraction holding the particles together. The strength of this force determines the state of the matter.
A diver can easily cut through water because the particles of liquid matter (water) have relatively weak forces of attraction between them, and there is enough space between the particles to let the diver's body push through.
What is the Carbylamine Reaction? (Isocyanide Test)
Learn about the Carbylamine reaction in organic chemistry. Understand how this test is used to identify primary amines by producing foul-smelling isocyanides.
Cation and Anion — Definition, Examples and Difference
Cations are positively charged ions (lose electrons); anions are negatively charged ions (gain electrons). Definition, examples Na⁺, Cl⁻, and differences explained.
What is the Full Form of CBG?
Learn the full form of CBG. Discover what Compressed Bio Gas is, how it is produced from agricultural waste, and its benefits as a green automotive fuel.
What are the Characteristics of the Particles of Matter?
Learn the 4 main characteristics of the particles of matter. Understand kinetic theory, intermolecular space, and forces of attraction.
Charge on an Alpha Particle — Value, Formula & Explanation
Charge on an alpha particle is +2e or +3.204 × 10⁻¹⁹ C. An alpha particle is a helium-4 nucleus with 2 protons and 2 neutrons, carrying a net +2 positive charge.
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