2.1Energy Transfer By Conduction Flashcards
What is thermal conductivity?
Thermal conductivity is a measure of how easily energy transfers through a material by conduction. Higher thermal conductivity means more energy is transferred per second.
Rank the thermal conductivity of metals, glass, and wood.
Metals (best conductors)
Glass (better than wood)
Wood (poorest conductor).
What factors affect energy transfer through a material by conduction?
Temperature difference across the material.
Thickness of the material.
Thermal conductivity of the material.
How can you reduce energy transfer through insulation?
Use materials with low thermal conductivity.
Make the insulating layer as thick as practically possible.
Why is fiberglass a good insulator?
Fiberglass traps air between fibers, and air is a poor conductor of heat.
What is the purpose of testing rods with wax in the conduction experiment?
To compare thermal conductivity of materials; the wax melts fastest on the rod with the best thermal conductivity.
Describe an investigation to determine the effect of material thickness on energy transfer.
Wrap different thicknesses of insulating material around a container of hot water, measure the water temperature at fixed intervals, and compare the rate of heat loss.
Why are materials with low thermal conductivity used as insulators?
They transfer less energy per second, reducing heat loss or gain.
What key property makes metals better conductors than non-metals?
Metals have free electrons that transfer energy efficiently.
