Astronauts experience weightlessness because they are in free fall, continuously falling toward Earth but also moving forward at high speeds. This creates a state of constant free fall, so they feel weightless.

The pressure in a car tire is higher than the surrounding atmosphere to maintain the tire’s shape and rigidity, ensuring proper contact with the road for stability and traction.

A parachute increases air resistance or drag, which slows the skydiver's descent by creating a large surface area that pushes against the air.

The blue color of the sky is due to Rayleigh scattering, where shorter wavelengths (blue light) are scattered more by molecules in the atmosphere than longer wavelengths (red light).

A rough sole increases the friction between the shoe and the ice, providing better grip and making it easier to walk. Smooth shoes would slide more easily on ice.

Light travels much faster than sound. Light from the lightning reaches us almost instantly, while the sound of thunder takes longer to travel due to its lower speed.

Cold temperatures cause the air inside the tire to contract, leading to a decrease in pressure. This is why tire pressure often needs to be checked more frequently in cold weather.

An echo occurs when sound waves reflect off a surface and return to the listener after a delay. This is most noticeable in large, empty spaces where sound waves can travel and reflect back clearly.

The curved upper surface of an aircraft wing causes the air above the wing to travel faster than the air below, creating lower pressure above the wing. This pressure difference generates lift, helping the plane to rise.

Metal has higher thermal conductivity, meaning it can absorb heat from the surroundings and transfer it to the ice cube more efficiently, causing it to melt faster.