30 terms

Unit 5 Review - thermal energy

STUDY
PLAY
Thermal energy
The amount of movement of the particles that make up a substance. Also called "heat"
"cold energy"
Not really a thing. Just a way of saying less thermal/heat energy
Is heat matter?
No, it does not have atoms, mass, or volume
Hotter matter to colder matter
The direction or way that thermal energy/heat moves
Equilibrium
When thermal energy/heat STOPS moving, when the substances are the SAME temperature
Definition of conduction
Transfer of thermal energy due to direct contact. The thermal energy is PASSED directly from molecule to molecule. No matter moves its position.
Definition of convection
Transfer of thermal energy through currents in a fluid. The thermal energy is CARRIED by moving molecules of liquid or gas. Matter moves.
Definition of radiation
Thermal energy transfer via electromagnetic waves, the thermal energy "JUMPS" from one substance to another without the need for matter.
CLASSIFY: Shirt being pressed by a hot iron
Conduction because the shirt and the iron are in direct contact. The thermal energy is passed from the molecules of the iron to the molecules of the shirt.
CLASSIFY: Feeling the heat of a campfire while sitting far away from it
RADIATION because the thermal energy "jumps" from the fire to you via EM waves without the need for matter.
CLASSIFY: Heated goo (liquid) in a lava lamps rises while the cooler goo (liquid) sinks in a cool swirly pattern
CONVECTION because the thermal energy is carried by the moving goo (liquid) molecules.
CLASSIFY: A cat sits on a shelf above the stove to stay warm.
CONVECTION because the air molecules are warmed by the stove, rise to where the cat is sitting and then sink back down as they cool.
CLASSIFY: On a hot, sunny August day, your Dad gets a sunburn out by the pool
RADIATION because the thermal energy "jumps" from the Sun to your Dad via EM waves, without the need for matter.
CLASSIFY: Using pot holders to pull a pan out of the hot oven
CONDUCTION because the pot holders slow/prevent the thermal energy transfer due to direct contact of your hand to the pan, thermal energy is passed more slowly from the molecules of the pan to the pot holder to your hand.
CLASSIFY: A pool heater causes the water near the surface of the pool to be warmer on a cloudy day
CONVECTION because the thermal energy is carried by the water molecules that rise toward the surface of the pool as they are heated and sink back to the bottom of the pool as they cool.
CLASSIFY: A huge rock is warmed by the Sun
RADIATION because the thermal energy "jumps" from the Sun to the rock via EM waves without the need for matter.
CLASSIFY: A piece of hair is curled by a hot curling iron
CONDUCTION because there is thermal energy transfer due to direct contact from the curling iron to the hair. The thermal energy is passed from the molecules of the curling iron to the molecules of the hair.
CLASSIFY: The vinyl siding on a house is melted/warped by a house fire across the street
RADIATION because the thermal energy "jumps" from the one house to the other via EM waves without the need for matter.
Definition of an insulator
Type of matter that blocks or reduces the flow of heat, electricity, or sound.
Cotton, fleece
These are specific examples of insulating materials. They reduce or block the flow of heat energy.
Definition of conductor
Type of matter that allows heat, sound or electricity to pass through it easily.
Copper, aluminum
These are specific kinds of conductors because they allow heat to pass through easily.
Why metal objects feel "cold" to us when we touch them with our hand
The thermal energy is transferred from our hand (the hotter matter) to the metal object (colder matter) easily since the metal is a conductor.
When thermal energy increases
The speed of the atoms/molecules of a substances increases.
When water vapor condenses into liquid water, then freezes into solid ice
Particles slow down in speed and get closer together in arrangement.
One POSITIVE reason that groups used aluminium foil in their penguin shelter
Aluminum foil can help to reflect some of the radiation from the heat lamps due to its shiny, reflective surface.
One possible NEGATIVE aspect to groups using aluminium foil in their penguin shelter
Aluminium is a metal and a conductor, so it could have let thermal energy pass into the shelter fairly easily, especially when used on the bottom!
Relationship (link) between thermal energy and temperature
As thermal energy increases, the molecules/atoms move more quickly, and the temperature of an object increases.
Purpose of the materials testing BEFORE designing/building (why we did it first!)
To see which materials were good or poor insulators and make an informed decision of which materials to use in the group penguin shelter.
Requirements/constraints (rules) were necessary in the save the penguins project....
Make save the penguins FAIR for all groups, to make REALISTIC shelters for a real world problem, and to model the engineering design process (the way engineers plan and build things in the real world!)