Explanation

• The sky appears blue due to Rayleigh scattering of sunlight by the atmosphere.
• Shorter wavelengths like blue light scatter more than longer wavelengths (red, yellow).
• The scattered blue light reaches our eyes, making the sky appear blue.
• Red light is less scattered and passes through the atmosphere.

Last verified on 17-03-2026

Explanation

• Blood vessels and capillaries are part of the circulatory system.
• They transport blood throughout the body, ensuring oxygen and nutrients reach tissues.
• Veins specifically carry blood towards the heart, while arteries carry blood away from the heart.
• Capillaries connect arteries and veins and allow exchange of oxygen, nutrients, and waste.

Last verified on 17-03-2026

Explanation

• Air is essential for plants because they need gases from the air for survival and growth.
• Plants take carbon dioxide (CO₂) from the air during photosynthesis to make their food.
• They also use oxygen (O₂) from the air for respiration to release energy.
• Without air, plants cannot perform important life processes.

Last verified on 16-03-2026

Explanation

• Dilution refers to the process of decreasing the concentration of a solution by adding more solvent.
• While ionisation involves the formation of ions from molecules in a solution.

Last verified on 16-03-2026

Explanation

• Gear is a wheel with teeth along its edge that interlock with another gear to transmit motion and force.
• Gears are used to increase or decrease speed, change direction, or increase torque in machines.
• Common in clocks, bicycles, vehicles, and industrial machines.

Last verified on 16-03-2026

Explanation

• Copper is a chemical element with the symbol Cu and atomic number 29. 
• It is a soft, malleable, and ductile metal with a reddish-orange color.

The some major elements with their symbols:

• Hydrogen - H
• Sodium - Na
• Carbon - C
• Nitrogen - N
• Oxygen - O
• Fluorine - F
• Chlorine - Cl
• Potassium - K
• Helium - He
• Neon - Ne
• Calcium - Ca
• Sulphur - S
• Phosphorus - P
• Aluminium - Al
• Magnesium - Mg
• Iron - Fe

Last verified on 16-03-2026

Explanation

• Sound waves first enter the ear through the Ear Canal.
• It is also known as the external auditory meatus.
• From there, they travel to the eardrum, then to the cochlea, and finally to the auditory nerve.

Last verified on 15-03-2026

Explanation

• Transmission is the process where light passes through a material without being absorbed or reflected.
• The light may pass completely unchanged if the material is transparent.

Additional information:

• Reflection – Light bounces back from a surface
• Absorption – Light is taken in by a material and converted to heat
• Refraction – Light bends while passing from one medium to another (like air to water)

Last verified on 15-03-2026

Explanation

Gears can:

• Change speed: Gears can increase or decrease
• Change direction: Gears can change the direction of rotation
• Change force: Gears can increase or decrease the force

However, gears cannot change the fulcrum, which is the pivot point or axis of rotation.

Last verified on 15-03-2026

Explanation

• Fuel stores energy in the form of chemical bonds.
• When fuel burns in the engine, this chemical energy is converted into mechanical energy to move the car.
• Gasoline, diesel, and natural gas are common fuels storing chemical energy.
• The process of burning fuel to release energy is called combustion.

Last verified on 15-03-2026