Explanation

• The value 332 m/s is measured under standard atmospheric conditions.

Additional information:

• Speed of sound in air at 20°C ≈ 343 m/s.
• Speed of sound is faster in solids than liquids and gases.

Examples:

• Air: ~332 m/s (0°C)
• Water: ~1,480 m/s
• Steel: ~5,100 m/s

Last verified on 21-07-2026

Explanation

• The Aorta is the largest artery in the human body.
• It carries oxygen-rich blood from the left ventricle of the heart to the rest of the body.
• It is the main artery of the systemic circulatory system.
• The aorta branches into smaller arteries to supply blood to all body organs except the lungs.

Additional information:

• Arterioles are the smallest branches of arteries.
• They carry oxygenated blood from arteries to the capillaries.
• Arterioles regulate blood flow and blood pressure by constricting or dilating.

Last verified on 21-07-2026

Explanation

• The age of the Universe is approximately 13.8 billion years.

Additional information:

• Age of the Earth: ≈ 4.54 billion years
• Age of the Solar System: ≈ 4.6 billion years
• Age of the Milky Way: ≈ 13.6 billion years
• Big Bang: Occurred about 13.8 billion years ago

Last verified on 20-07-2026

Explanation

• Light Year is the distance that light can travel in one year.
• The distance light travels in one year is known as light year.
• 1 light year is equal to 9.5 x 10¹²km.

Last verified on 30-03-2026

Explanation

• Discoverer: Alexander Fleming
• Year of discovery: 1928
• Place: St. Mary's Hospital, London
• First patient treated with penicillin: Albert Alexander
• Date of first treatment: 12 February 1941

Last verified on 01-07-2026

Explanation

• Weber (Wb) is the SI unit of magnetic flux.
• One Weber is equal to one volt-second (V·s).
• A magnetic flux density of 1 Weber per square metre (1 Wb/m²) is equal to 1 Tesla (T).
• Magnetic flux measures the total magnetic field passing through a surface.

Last verified on 03-07-2026

Explanation

• Total standard zones: 24
• Earth rotation time: 24 hours
• Longitude per zone: 15 degrees
• Starting point: Greenwich (0°)
• It is used worldwide for time coordination.

Last verified on 14-06-2026

Explanation

• Mars is known as the Red Planet due to its reddish appearance.
• Its surface contains iron oxide (rust) which gives it a red color.
• It is the 4th planet from the Sun in the solar system.
• Mars has two small moons: Phobos and Deimos.
• Mars is often called the “planet of future exploration”.

Last verified on 12-06-2026

Explanation

• Mitochondria are called the powerhouse of the cell.
• Because they produce Adenosine Triphosphate (ATP).
• ATP is the energy currency of the cell.
• ATP provides energy for different cellular activities such as movement, growth, and transport.
• Energy is produced through aerobic cellular respiration using oxygen and الغذائی molecules.
• They are found in the cytoplasm of most eukaryotic cells.
• Richard Altmann first described mitochondria in 1890.

Main Parts of a Cell:

1. Cell membrane → Outer protective layer
2. Nucleus → Controls cell activities
3. Cytoplasm → Jelly-like material between membrane and nucleus

Last verified on 09-05-2026

Explanation

• The hardest substance in the world is diamond.
• Its hardness is due to the strong covalent bonding between its carbon atoms.
• This making it the most resistant to scratching.

Additional information:

• Category: Native minerals
• Cleavage: 111 (perfect in four directions)
• Crystal class: Hexoctahedral (m3m); H-M symbol: (4/m 3 2/m)
• Crystal habit: Octahedral
• Crystal system: Cubic
• Dana classification: 1.3.6.1
• Density: 3.5–3.53 g/cm3 3500–3530 kg/m3

Last verified on 07-06-2026