Themal Transfer Of Energy Unit 1 Flashcards
Temperature is….
A measure of the average kinetic energy of all the particles in a substance
At a higher temperature, particles move____ and become ____ while at a lower temperature, particles move____ and ____
Faster, further apart, slower, move closer together
Heating is a process where by…
A net amount of energy is transferred across a system due to a temperature difference
Energy is transfered from a region of____ temperature to a region of_____ lower temperature
Higher, lower
When two objects are at the same temperature…
They are in thermal equilibrium where there will no longer be any net transfer of energy
Conduction is a process of energy transfer…
Through passing of vibrational motion from one particle to another, without net transfer of particles
Particles in solids are
Very closely packed in an orderly manner (energy can be transfered more quickly between particles, thus are better conductors than liquid and gas)
Particles in liquid are…
Closely packed in a disorderly manner
Particles in gas are…
Far apart from each other and are randomly arranged
Metals are good thermal conductors as they have…..
A giant metallic lattice structure, which allows the presence if free moving electrons (sea of delocalised electrons) . The electrons near the heat source move faster, collide with neighbouring electrons, transfer energy. The vibration of cations in lattice structure hit the electrons, making the electrons move faster and hit cations further away rather than neighbouring ones. This speeds up the process of conduction
Wood, ruber, plastic, glass, most liquids (except mercury) and air are…
Poor thermal conductors
When a metal is heating up energy is absorbed by electrons and their kinetic energy increases, ….
Thus they start moving rapidly towards the colder end of the metal block. Kinetic energy us transfered to the colder end via collisions
Convection is…
A process of energy transfer by convection currents in a fluid (gas or liquid), due to a difference in density
Describe convection currents
The water particles in the warmer region/nearer to the heat source gain kinetic energy, thus move faster and spread further apart, which results in those particles becoming less dense. They then rise to the top and replace the colder, denser particles which sink to the bottom, replacing the warmer particles. These colder particles then heat up and the whole process repeats, forming a convection current
Radiation is…
The transfer of energy by electromagnetic waves and does not require a medium unlike conduction and convection
Energy transferred via radiating is also known as _______ and is emitted by ________ as long as the object’s temperature is ________
Radiant energy, all surfaces, above 0 Kelvin
What texture and color of surface, and surface area are good emitters and absorber of radiation? The opposite?
Good emitters & absorber of radiation are rough, dark and large surface area surfaces while bad emitters and absorbers of radiation are smooth, light and small surface area surfaces
The higher the temperature of an object, the ____ energy is radiated
More
Explain sea breezes
The land absorbs and radiates radiation faster than the sea during the day, thus the air above the land is warmer than the air above the sea. As the warm air above the land rises, the cooler air over the ocean flows across the land surface to replace the rising warm air, forming sea breezes
Explain land breezes
The land cools faster than the sea at night, causing the air above the land to be colder and denser than the air above the sea. The warmer air above the sea rises while the cooler air from the land flows across the sea surface to replace the warmer rising air, forming land breezes.
