types of heat and energy transfer
why does dark clothing become hot on a sunny day
They absorb more radiation from the sun. lighter colors reflect more; for example Black absorbs all of the colors of light
conductors
materials that can transfer heat
insulators
materials that do not transfer heat through them as well
describe insulators
particles more spread out electrons don't separate easily Usually higher specific heat
what are the three ways heat energy is transferred?
radiation, conduction, and convection
how do you find specific heat
rearrange the equation for energy
specific heat
the amount of heat energy needed to raise the temperature of 1 kg of a substance by 1 K.
why are metals good conductors
they usually have high densities and their electrons can separate easily
thermal energy
total kinetic energy; something could have the same kinetic energy but different thermal energy
what are types of radiation
visible light, infrared(heat), UV rays, microwaves, gamma rays, X-rays, and radio waves
Could conduction happen between two objects that were not touching?
Conduction cannot happen between objects that are not touching because the particles need to collide in order to transfer energy
what is an example of convection
Convection is observed when air is heated by radiators and the warm air rises and cool air sinks and gets heated, or a the air above a fire, or the liquid in a pot of water on the stove
what is convection responsible for in nature
Convection is responsible for wind patterns and ocean currents and the magma that circulates in the Earth's mantle
what is the equation for energy
Energy = specific heat x mass x temperature change energy = cmΔT
what unit does the ΔT have to be
K, but bc C and K have the same scale, you do not need to convert to find ΔT if its in C
How is visible light transferred from the fire?
The fire gives off visible light through radiation
how does convection work
When a fluid is heated, the warm fluid rises because it is less dense than the cooler fluid surrounding it. As the warm fluid rises, the warmer fluid transfers energy and cools, then sinks back down as it cools, then gets heated again and rises. This creates a convection current.
how would Kelvin and Celsius thermometer differ
a K thermometer would not have negative numbers, the numbers would be higher, and there would not be a degrees symbol
why is air a poor conductor
air and other gases are to spread out to transfer energy by conduction quickly
what speed does radiation travel
all radiation travels at the same speed, known as speed of light
why is it good for us that water has a high specific heat
bc we are mostly water and it would be bad if we started boiling. Also if the water had low specific heat it would boil and kill the fishies
in what phase of matter does conduction most commonly occur
between or within solids
describe conductors
can transfer heat because of the way their atoms are closely packed together and their electrons can move around within the substance to transfer energy. Usually lower specific heat
what is an example of radiation
even though all objects radiate heat, the sun and fires are common, powerful sources. the sun radiates heat which warms the ground
convection current
forms when density differences cause a fluid to flow along a circular path.
convection
heat transfer by movement of matter due to differences in densities caused by differences in temperature; usually observed to occur in fluids
conduction
heat transfer that occurs by contact between objects or particles colliding within a substance
radiation
heat transfers out in all directions (radiates) from all objects and living things
what does an increase in temperature do to the kinetic energy
increases the kinetic energy
how does radiation transfer
it does not require matter for the heat to transfer, and it can travel through a vacuum (like outer space) because it is in the form of electromagnetic waves
what does it mean if something has a low specific heat
it does not take a lot of energy to raise the temperature
what does it mean if something has a high specific heat
it takes a lot of energy to raise its temperature, for example water's specific heat is in the 4000s
what is the unit for energy
joules (J)
what unit does the mass need to be in
kg
fluids
liquids and gases
what is an example of conduction
when you hold a cup of hot chocolate your hands get warm; when you stand on hot concrete your feet burn