Heats and heat transfer Flashcards
(30 cards)
What is temperature?
The average kinetic energy of random thermal motion of particles in an object
What is heat energy?
Heat energy is the total kinetic energy of random thermal motion of particles in an object
Do objects have kinetic energy when stationary?
Yes, the individual particles in the object have kinetic energy
How do you work out internal energy?
internal energy = kinetic energy + potential energy
What is potential energy?
It is the energy an object possesses due to its position or configuration
What is the formula for working out GPE?
GPE = mgh
m = mass (kg)
g = gravitational field strength (N/kg)
h = height (m)
What happens when you heat a particle up?
The particle’s average kinetic energy increases and the particle moves faster
What are insulators?
Insulators are poor conductors of heat so this means that the heat isn’t easily transferred away. An insulator doesn’t transfer heat very well which means the heat stays where it is for longer
What is the required practical on insulation trying to measure?
The rate of heat loss
What would have the slowest rate of heat loss?
The beaker with the most insulation
How does heat flow?
Heat flows from where it is hotter to where it is cooler so if you place a cold object in a hot environment, heat will flow into it
What are the 3 main ways that heat transfers?
Conduction
Convection
Radiation
What is conduction?
When applying heat to a metal, the electrons will pass heat energy across the atoms
What is heat to do with?
How much the atoms are vibrating. The more they vibrate, the hotter the substance is
Are non-metals good or bad conductors?
Bad because they dont have free electrons to pass on energy
What is convection?
Convection is when a liquid or gas is heated and therefore the particles move faster due to their increased energies and spread out, creating a less dense fluid. Then the warmer, less dense fluid rises up to the top and the cooler, less dense fluid sinks to the bottom. This creates a convection current.
What is space?
A place with no particles - a vacuum.
What is the only way heat can travel in space?
As infra-red electromagnetic waves
What is infra-red light?
It is like ordinary light but has a longer wavelength
What do all objects emit?
Heat radiation
The hotter an object the ____ heat radiation it emits
more
What do all objects absorb?
Some of the heat radiation that hits them from nearby objects
What colour body absorbs all the heat radiation that hits it?
Black
What happens if an object absorbs more heat radiation than it emits?
Its temperature increases
