chapter 5 section 2 Flashcards
(22 cards)
conduction def
transfer of thermal energy by collisions between particles in matter
why does conduction occur?
because particles in matter are in constant motion
think about the spoon example with conduction…
- as one end of the spoon heats up, the kinetic energy of the particles that make up that part of the spoon increases
- these particles collide with neighboring particles
- conduction transfers thermal energy to the other end of the spoon as particles with more kinetic energy transfer
T? or F?: Conduction transfers thermal energy while it transfers matter.
F: …thermal energy without transferring matter
how is thermal energy transferred?
by the collisions between particles, NOT by the movement of matter
T? or F?: Conduction spreads thermal energy from cooler to warmer areas.
F: …warmer to cooler areas.
what does the rate at which thermal energy is transferred depend on?
the material
thermal energy transfers by conduction fastest through what forms of matter?
solids and liquids
rather than gases
why does thermal energy transfer faster by conduction through solids and liquids?
particles that make up gases are further apart, so collisions between particles occur less frequently than they so for solids of liquids
best conductors for thermal energy are…
metals
why are the best thermal energy conductors metals?
there are electron that are not bound to individual atoms but can move easily throughout metals, because of this, collisions between these electrons and other particles in the metal enable thermal energy to be transferred more quickly than in other materials
convection def
the transfer of thermal energy through a fluid by the movement of warmer and cooler fluid from place to place
why are gases considered liquids?
both gases and liquids can ‘flow’ so they are both classified as fluids
what happens to particles when convection occurs?
more energetic particles move from one place to another, unlike the collisions of particles in conduction
T? or F?: more energetic particles means that they have higher speed.
T
T? or F?: as particles move faster, the tend to move closer together.
F: … tend to move farther apart; as a result the fluid expands as its temperature increases
expansion def
increased volume
remember, density
mass/volume (m/v)
so, as volume increases…
density decreases; the same is true for parts of fluid that have been heated
the density of warmer fluid is …
less than that of the surrounding cooler fluid
the warmer proportions of a fluid rise to the…
top of the fluid and the cooler portions sink to the bottom
is a fluid is heated from below…
convection currents form
