P1.1 - Everything in the Specification

[blank_start]Dark[blank_end], [blank_start]matt[blank_end] surfaces are [blank_start]good[blank_end] absorbers and [blank_start]good[blank_end] emitters of infrared radiation. [blank_start]Light[blank_end], [blank_start]shiny[blank_end] surfaces are poor [blank_start]absorbers[blank_end] and poor [blank_start]emitters[blank_end] of infrared radiation.

All objects emit infrared radiation.

The [blank_start]hotter[blank_end] an object is, the [blank_start]more[blank_end] infrared radiation it radiates in a given time.

Light, matt surfaces are good reflectors of infrared radiation.

[blank_start]GASES[blank_end] - There are almost no [blank_start]forces of attraction[blank_end] between [blank_start]gas[blank_end] particles, so they move [blank_start]randomly[blank_end] in all directions at [blank_start]high speeds[blank_end] and there is lots of [blank_start]space[blank_end] between the particles.

[blank_start]SOLIDS[blank_end] - There are [blank_start]strong forces of attraction[blank_end] between [blank_start]solid[blank_end] particles, so they are unable to move [blank_start]around[blank_end] and [blank_start]pass[blank_end] each other, and there is [blank_start]no space[blank_end] between the particles. The particles are held in fixed positions in a [blank_start]regular arrangement[blank_end].

[blank_start]LIQUIDS[blank_end] - There are [blank_start]weak forces of attraction[blank_end] between [blank_start]liquid[blank_end] particles, so the particles are [blank_start]free to[blank_end] move around [blank_start]at random[blank_end] but with [blank_start]lower[blank_end] speeds than in the [blank_start]gas[blank_end], and the particles are [blank_start]relatively[blank_end] close together.

[blank_start]Solids[blank_end] have [blank_start]the least[blank_end] kinetic energy. Gases have [blank_start]the most[blank_end] kinetic energy. [blank_start]Liquids[blank_end] have some kinetic energy.

CONDUCTION - A process of heat [blank_start]transfer[blank_end] by particles [blank_start]vibrating[blank_end] against each other (in a [blank_start]solid[blank_end]) or [blank_start]collisions[blank_end] between particles (in a [blank_start]gas[blank_end] or [blank_start]liquid[blank_end]). Conduction is the main mode of heat [blank_start]transfer[blank_end] in a [blank_start]solid[blank_end].

CONVECTION - A process of heat [blank_start]transfer[blank_end] via particles, involving the bulk [blank_start]movement[blank_end] of [blank_start]liquid[blank_end] or [blank_start]gas[blank_end] particles. Convection cannot take place in [blank_start]solids[blank_end].

RADIATION - A process of heat [blank_start]transfer[blank_end] via [blank_start]electromagnetic[blank_end] [blank_start]waves[blank_end]. Infrared radiation is [blank_start]absorbed[blank_end] and emitted by all objects.

THE PROCESS OF CONDUCTION IN SOLIDS: 1. Some [blank_start]particles[blank_end] gain [blank_start]thermal[blank_end] energy. 2. They [blank_start]vibrate[blank_end] more strongly, as they have more [blank_start]kinetic[blank_end] energy. 3. They [blank_start]collide[blank_end] with other, cooler particles, transferring [blank_start]kinetic[blank_end] energy. 4. So [blank_start]thermal[blank_end] energy is transferred from a [blank_start]hotter[blank_end] to a [blank_start]colder[blank_end] region.

THE PROCESSES OF CONDUCTION IN METALS: 1. [blank_start]Delocalised electrons[blank_end] are free to move in metals. 2. Some [blank_start]electrons[blank_end] gain [blank_start]thermal[blank_end] energy. 2. They [blank_start]move more rapidly[blank_end], as they have more [blank_start]kinetic[blank_end] energy. 3. They [blank_start]collide[blank_end] with other, cooler electrons, transferring [blank_start]kinetic[blank_end] energy. 4. So [blank_start]thermal[blank_end] energy is transferred from a [blank_start]hotter[blank_end] to a [blank_start]colder[blank_end] region.