15 source-checked questions. A library, not live AI.
Air molecules scatter blue light more than red light. That scattered blue light reaches our eyes from across the sky.
A clear daytime sky can look blue even though sunlight contains many colours.
Source: NASA Space Place. Checked 7 October 2026.
At sunset, light travels through more atmosphere before reaching you. Much of the blue light is scattered away from the direct path, leaving more red and yellow light.
A low Sun can look warmer in colour than the midday Sun.
Source: NASA Space Place. Checked 7 October 2026.
Thermal energy moves through the metal from the hotter end to the cooler end. This is conduction.
The handle can warm up even if it is not under the tea. Never test this with a very hot spoon.
Source: OpenStax: Heat transfer. Checked 7 October 2026.
At the same room temperature, tile usually takes heat from your feet faster than carpet does. The faster heat loss makes it feel colder.
Two surfaces can be equally warm on a thermometer but feel different to your hand.
Source: OpenStax: Heat transfer. Checked 7 October 2026.
Insulation slows heat transfer between a drink and its surroundings. It does not make hot contents stay hot forever.
A covered insulated flask generally loses heat more slowly than a thin uncovered cup.
Source: OpenStax: Heat transfer. Checked 7 October 2026.
Energy reaches them as electromagnetic radiation. An object that absorbs some of this energy can warm up.
Sunlight warming a wall is heat transfer by radiation.
Source: OpenStax: Heat transfer. Checked 7 October 2026.
Convection transfers heat through the movement of a liquid or gas. Moving fluid carries thermal energy from one place to another.
Warm air moving upward from a heater is one example.
Source: OpenStax: Heat transfer. Checked 7 October 2026.
Net heat transfer is from a hotter region to a colder region. At equal temperatures there is no net heat flow between them.
A warm drink tends to cool in a cooler room.
Source: OpenStax: Heat transfer. Checked 7 October 2026.
A vibrating source disturbs surrounding matter. The disturbance travels outward as a sound wave.
A plucked string vibrates and sets nearby air into motion.
Source: OpenStax: Sound. Checked 7 October 2026.
Yes. A sound wave transfers energy through the material it travels through. The material vibrates as the disturbance passes.
A loudspeaker sets the surrounding air into vibration.
Source: OpenStax: Sound. Checked 7 October 2026.
Its energy spreads over a larger area as it travels. Some energy is also absorbed along the way.
A voice is usually harder to hear across a large field than close by.
Source: OpenStax: Sound. Checked 7 October 2026.
Air is alternately compressed and spread out as the pressure disturbance travels. The air particles vibrate rather than travelling all the way from the source to your ear.
A speaker sends pressure changes through the air.
Source: OpenStax: Sound. Checked 7 October 2026.
Some liquid water changes into water vapour and enters the air. This process is evaporation.
A wet shirt loses water as it dries on a line.
Source: USGS: Evaporation. Checked 7 October 2026.
Yes. Evaporation can occur at the surface of liquid water without the whole liquid boiling.
A puddle can shrink on a day when it is nowhere near boiling temperature.
Source: USGS: Evaporation. Checked 7 October 2026.
Water vapour in the nearby air cools and changes into liquid water on the cold surface. This is condensation.
A cold drink can collect drops even when the cup has no leak.
Source: USGS: Condensation. Checked 7 October 2026.