SL SEHS - A.2 Environmental Factors & Physical Performance

The transfer of heat from one object/body to another (in direct physical contact with one another), is know as:

Conduction

The transfer of heat from one object/body to air or water (gas or liquid) is know as:

Convection

The transfer of heat from one object/body to another, not in direct physical contact with one another and separated by space, via infrared /electromagnetic waves is know as:

Radiation

The transfer of heat as water changes state from liquid to gas, is know as:

Evaporation

This is the method by which most of the heat is gained or lost to/from the body. This account for around 40-60% of heat gained of lost to/from the body.

Radiation

This method of heat transfer accounts for approximately 15 % of heat lost from the body.

Convection

This is the method by which least of the heat is lost/gained from/to the body. This method accounts for approximately 2-10% of heat loss/gain, depending on the object in contact with the body.

Conduction

At rest this method accounts for around 20% of heat lost from the body. However during exercise it can account for as much as 80%.

Evaporation

This method of heat transfer occurs when heat that has left the body is carried away by moving air/water. This allows more cool air/water to move next to the skin and absorb more heat.

Convection.

Changing water from liquid to gas requires energy which uses heat energy, and removes heat from the body. Which method of heat transfer does this happen in?

Evaporation

This method of heat transfer or loss is increased if there is low humidity (moisture/water in the air).

Evaporation

This method of heat transfer or loss is increased if the air/water moves quicker around the body, i.e. fast moving air /wind and decreased if the air/water moves slowly.

Convection

These methods of heat transfer (gain or loss) are increased if a person has a large surface area to body mass ratio.

Tall heavy people for example have a small body surface area to mass ratio. Small children for example have a large body surface area to mass ration.

Convection, radiation & conduction

These are the methods by which the body can gain heat from the surrounding environment.

Conduction & Radiation

These are the methods by which the body can lose heat to the surrounding environment.

Conduction, Radiation, Convection & Evaporation

Heat can be generated in the body through what process?

Cellular metabolism. Breaking down ATP releases 60% of energy in the form of heat energy.