Heat Transfer Flashcards
What are the three modes of heat transfer?
The three modes of heat transfer are conduction, convection, and radiation.
What is conduction?
Conduction is the transfer of heat through a material without the movement of the material itself. It occurs when heat energy is passed from molecule to molecule within a substance.
What is convection?
Convection is the transfer of heat by the movement of fluids (liquids or gases). It occurs when warmer areas of a liquid or gas rise to cooler areas, causing a circulation pattern.
What is radiation?
Radiation is the transfer of heat in the form of electromagnetic waves, such as infrared radiation, without the need for a medium (like air or water).
What is a temperature gradient?
A temperature gradient is the rate of change of temperature with distance within a material. It drives the flow of heat by conduction.
What is thermal conductivity?
Thermal conductivity is a property of a material that indicates its ability to conduct heat. Materials with high thermal conductivity, like metals, transfer heat more efficiently than those with low thermal conductivity, like wood or rubber.
What is heat flux?
Heat flux is the rate at which heat energy passes through a surface per unit area, often measured in watts per square meter (W/m²).
How does the nature of a surface affect the energy it radiates and absorbs?
Dark, rough surfaces absorb and radiate more energy than light, smooth surfaces. This is why black surfaces tend to get hotter in the sun compared to white surfaces.
How does a thermos flask minimize heat transfer?
A thermos flask minimizes heat transfer through its vacuum layer, which reduces conduction and convection, and its reflective inner surface, which reduces radiation.
How can you differentiate between conduction, convection, and radiation?
Conduction involves heat transfer through direct contact of molecules, convection involves the movement of fluids to transfer heat, and radiation transfers heat through electromagnetic waves without needing a medium.
