efficiency steam combustion electric

Re: Earth wind & fire,
Until …, fire was believed to be a fluid form of matter.

Examples:

Ice cube in coffee cup - heat flows naturally from hot to cold.

Air conditioner and Refrigerator - evaporator, compressor, condenser, refrigerant, fan. Heat flows in opposite of natural direction and this requires external energy in the form of electricity.

Transfer of heat, three methods:

• Convection
• Conduction
• Radiation

molecule to molecule

Conduction works well in solids particularly metals. Liquids and non-metallic solids very in their ability to conduct heat but gas is always a poor conductor of heat.

The characteristics that make metal a good conductor of heat also make it a good conductor of electricity.

moving hot molecules among cold molecules, in a fluid, gas or liquid.

Hot air is less dense than cold air.

Hot air rising from the land on a sunny day - natural convection.

Oven - forced convection.

Fridge - forced convection in the opposite direction.

Heart - natural convection. a pump circulates blood which moves excessive heat out to the skin where it moves to sweat which is evaporated.

While Convection and conduction involve thermal energy,

Radiation involves electromagnetic energy.

The electromagnetic spectrum includes:

• visible light,
• infrared light,
• ultraviolet light,
• x-rays,
• gamma rays,
• radio waves,
• microwaves for TV and radar.

Any glowing object is an example of radiation: The sun, a fire, a light bulb.

We can see the radiation of visible light.
We can feel as heat the radiation of infrared and ultraviolet light.

there is no definitive phrasing; instead, there are various versions, all of which say the same thing.