Document page
igcse physics notesprinted 81 · PDF 81
124 pagesrevision 46936
printed 81 · PDF 81
Page image rendered from the stored file at 110 dpi; it sharpens as you zoom. Outlines are placed from each region’s stored position on the page (612 × 792 pt).
readable
Source of this text: embedded text layer. The better of the embedded text and OCR is kept.
81
As shown in the above image, thermal conduction also occurs due to free
moving electrons in metals whereas in glass thermal conduction is slow
due to no free moving electrons.
Conduction in gases and liquids:
Gases and liquids are poor conductors of heat because the particles in
these states of matter are spread out and move around easily, making it
difficult for vibrations to pass from one particle to another.
The particles in liquids are close together but can slide past each other.
The weaker intermolecular forces and more space between the particles
make it harder to transmit vibrations.
The particles in gases are widely spread apart, so they don't "nudge" each
other when they vibrate. The particles in gases have even more space than
in liquids, so they collide infrequently.
In contrast, solids are better conductors of heat because the particles are
closely packed together, allowing vibrations to easily transfer from one
particle to the next.
Examples of bad conductors:
Handles of all cooking materials
Sheet of thermocol
Fiber