Explanation

• A Barometer is an instrument used to measure air (atmospheric) pressure.
• It helps in weather forecasting by measuring changes in atmospheric pressure.
• The mercury barometer is the oldest type of barometer.
• It was invented by Evangelista Torricelli in 1643.
• Barometers are widely used in meteorology and aviation.

Last verified on 09-07-2026

Explanation

• The amplitude of a sound wave determines its loudness.
• Greater amplitude generally produces a louder sound.
• While smaller amplitude produces a quieter sound.

Additional information:

• Frequency: Determines pitch (high or low sound).
• Wavelength: The distance between two consecutive points in the same phase, such as two crests.

Last verified on 15-10-2026

Explanation

• A velocity–time graph shows how velocity changes with time.
• The slope gives acceleration.
• The area under the graph represents motion covered.
• It connects velocity with displacement.

Last verified on 22-05-2026

Explanation

• The speed of sound is generally maximum in solids.
• Because their particles are closely packed and elastic forces transmit vibrations rapidly.

Additional information:

• Solids: Sound generally travels fastest, e.g., Steel: 5,000–6,000 m/s
• Liquids: Sound travels slower than in most solids, e.g., Water: 1,480 m/s
• Gases: Sound travels slowest under ordinary conditions, e.g., Air at 20°C: 343 m/s

Last verified on 15-10-2026

Explanation

• Rusting of iron is a chemical change.
• Because iron reacts with oxygen and moisture to form rust (hydrated iron oxide).
• A new substance is formed, and the change cannot easily be reversed.
• Rusting is a slow oxidation process that occurs in the presence of oxygen and water.
• Other examples of chemical changes: Burning wood, cooking food, and digestion.

Last verified on 15-10-2026

Explanation

• Smallest bone: Stapes.
• Location: Middle ear.
• Three ear bones: Malleus, Incus, Stapes.

Additional information:

• Longest bone: Femur (thigh bone).
• Adult human skeleton: Usually 206 bones.
• Newborn: About 300 bones at birth; many later fuse together.
• Human skull: 22 bones (8 cranial + 14 facial)

Last verified on 03-09-2026

Explanation

• Diffusion is the natural movement of particles from an area of higher concentration to lower concentration without external force.
• It occurs in gases, liquids, and even solids to some extent.

Last verified on 14-10-2026

Explanation

• Earth is called the Blue Planet.
• About 71% of Earth's surface is covered by water.
• Water makes Earth appear blue from space.
• Earth is the third planet from the Sun.
• Earth’s natural satellite is the Moon

Last updated: NA on 26-09-2026

Explanation

• SARS-CoV-2: Coronavirus that causes COVID-19.
• First identified: Late 2019.
• Transmission: Mainly through respiratory particles.
• COVID-19: Stands for Coronavirus Disease 2019.

Last updated 07 Nov 2026 by NA

Explanation

• Genetics: Study of heredity and variation in organisms.
• An Austrian monk who experimented with pea plants in the 19th century is known as the "Father of Modern Genetics"

Additional information

• Ecology: Study of organisms and their environment.
• Anatomy: Study of the structure of organisms.
• Evolution: Study of how living organisms change over generations.

Last updated by NA on 06-11-2026