Quiz Class 9th Science 09-05-2026

Welcome To My School Study

Do You Know

1. Diffusion (Movement of Particles)

Diffusion is the process in which particles move from a region of higher concentration to a region of lower concentration.

Reason for diffusion:
Particles are always in continuous motion, so they spread naturally.

Important Points:

• Diffusion occurs in solids, liquids, and gases
• It is fastest in gases because particles move freely

Examples:

• Smell of perfume spreading in a room
• Ink spreading in water

Importance:
Diffusion helps in mixing substances naturally.

2. SI Unit of Force – Newton (N)

Force is measured in Newton (N), which is the SI unit of force.

Meaning of force:
Force is a push or pull that can change the motion or shape of an object.

Formula:
Force = Mass × Acceleration

Named after:
Sir Isaac Newton

Examples:

• Pushing a door
• Pulling a cart
• Kicking a football

Importance:
Force is required to move, stop, or change the direction of objects.

3. Electron – Negatively Charged Particle

An electron is a tiny subatomic particle present outside the nucleus of an atom.

Charge on electron:

• Negative charge

Comparison with other particles:

• Proton → positive charge
• Neutron → neutral
• Electron → negative charge

Importance:
Electrons are responsible for electric current and chemical bonding.

Example:
Flow of electrons in wires produces electricity.

4. Formula of Speed (Distance ÷ Time)

Speed tells us how fast an object moves.

Formula:
Speed = Distance ÷ Time

Understanding:

• Greater distance in less time → higher speed
• Smaller distance in more time → lower speed

Units of speed:

• m/s (meter per second)
• km/h (kilometer per hour)

Examples:

• Speed of a car
• Running speed of an athlete

Importance:
Speed helps compare the motion of different objects.

5. Function of Muscle Tissue (Movement)

Muscle tissue helps in the movement of the body.

How muscles work:
Muscles contract and relax to produce movement.

Types of muscle tissue:

• Skeletal muscles → movement of bones
• Smooth muscles → movement inside organs
• Cardiac muscles → movement of the heart

Importance:
Muscles help in walking, running, breathing, and other body movements.

Example:
Arm muscles help lift objects and perform physical activities.