Chapter 9: Heat Flashcards
What is heat?
energy that makes an object hot
What is another name for the energy from Sun that is reflected back by clouds?
thermal energy
What is heat in humans?
digestion
metabolism
What is the difference between heat and temperature?
Heat:
- form of energy
- object absorb heat=hotter
- object loses heat = colder
- measured in joule(J)
- flows from hotter to cooler
Temperature:
- the measure of degree of hotness or coldness of an object
- thermometer is used
- Unit: celcius(℃) and kelvin (K) [Extra: Farenheit(℉)]
What are the factors that affect heat?
TQT=抬起头,太阳在那儿(tai yang=heat)
Type
Quantity
Temperature of material
What are the factors that affect temperature?
degree of movement of particles
Why when a spark fall on your hand, you don’t feel any pain, but a few drops of boiling water will?
Amount of heat in the spark is less than the amount of heat in the drops of boiling water
Does two objects at the same temperature have the same amount of heat
No, objects at the same temperature may not have the same amount of heat
From which temperature to which temperature does heat energy travels to?
Higher temperature to lower temperature
What is the relationship between the difference in temperature and heat flow?
The greater the difference in temperature, the faster the heat flows
State 3 ways that heat travels.
- convection
- conduction
- radiation
What is conduction?
The process at which heat flows from the hot to the cold end of solid
Do particles in the medium flow?
no
try to explain the concept of conduction.
the particle of the solid are arranged very
closely together (1),
particle that recieve heat energy directly vibrate FASTER, collide with neighbouring particle FREQUENTLY(2),
in this way heat is transferred to the cold end of spoon (3)
What is convection?
The process in which heat is transferred from one place to another by particles which move (move to transfer)
What does convection occur in?
liquids and gases
Try to explain convection.
When fluid is heated, it expands and becomes less dense, causing it to move upwards (1)
The cold and dense fluids moves downwards to take it’s place (2)
This in turn gets heated and rises and repeats the cycle (3)
What is radiation?
The transfer of heat through vacuum
Does radiation require any medium?
no
Give an example of radiation.
The heat of the Sun is transferred to the Earth by radiation
Can the thermometer be placed on top of the lighted bulb?
wants to have the temperature through radiation
No, to prevent heat from beig transferred to the thermometer through convection, since hotter air goes up