AKS 7c/7d Remediation CIA

© The Science Duo

Heat

Transfer

Heat

•
Heat is also referred to as thermal energy

•
The form of energy associated with the movement of
atoms or molecules in a material

•
The particles of a warmer object move faster than the
particles of a cooler object

•
All matter has heat energy – some objects have more
or less than others

More Heat Energy

Less Heat Energy

Boiling Water

Ice Cubes

Thermal Equilibrium

•
The point when substances have reached the same
temperature and heat no longer flows between them

•
Example – A hot cup of coffee sitting on the counter will
reach room temperature after a few hours

Time (hr)

Coffee Temp.

Room Temp.

0

120° F

72° F

1

97° F

72° F

2

84° F

72° F

3

72° F

72° F

Thermal Equilibrium

Heat Transfer

•
The movement of thermal energy from one substance
to another

•
3 types of heat transfer – conduction, convection, and
radiation

•
Heat always transfers from substances with more
thermal energy to substances with less thermal energy
until both substances reach the same temperature

•
Example – Warmer air rushes into a refrigerator when
the door is open

Warmer Air

Conduction

•
The transfer of heat from one substance to another
through direct contact

•
Conduction occurs most commonly with solids, but can
occur with liquids and gases as well

•
Conduction = direct contact

Examples of Conduction

Ice melting in

your hands

A metal spoon

in hot soup

Holding a hot
cup of coffee

Convection

•
The transfer of heat through currents caused by the
warming and cooling of liquids or gases

•
Travels through fluid materials – liquids and gases

•
Does not occur in solids because the particles of solids
are too tightly packed

Examples of Convection

Heat rising from

a chimney

Moving wind or
ocean currents

Cooking popcorn
with an air popper

Radiation

•
The transfer of heat through electromagnetic waves

•
Able to travel through empty space

•
Does not require matter to transfer energy

Examples of Radiation

Feeling the

warmth of the

Sun on your face

Roasting a

marshmallow
over a flame

Heat given off

from a light bulb

Multiple Choice

The heat from a hot burner to a pot is transferred by ______.

• convection
• insulation
• radiation
• conduction

Multiple Choice

The sun warming your skin is an example of heat transfer through 

• conduction
• convection
• radiation
• thermal electricity

Multiple Choice

Which example below is an example of convection?

• Standing on a hot metal bridge
• The attic is warmer than the basement
• The Sun heating the Earth
• Touching hot sand with your feet

Multiple Choice

Donald is heating up water on the stove in a tea kettle. Which of the following BEST describes the process by which the water in the kettle moves during the time it is being heated?

• The water circulates due to convection, which is caused by molecules colliding with each other and transferring energy from the colder molecules to the warmer ones.

• The water circulates in the tea kettle due to conduction, which is caused by the warmer and colder molecules mixing with each other.

• The water circulates in the tea kettle due to convection, which is caused by the motion of warm and cold fluids due to their different densities.

• The water circulates in the tea kettle due to radiation, which is caused by energy being absorbed by the tea kettle in contact with the burner.

Multiple Choice

Two iron rods are placed next to each other, with their ends touching. One end of one rod is heated. After some time, the other rod also feels warm to the touch. How did the heat travel from the heated rod to the one that was not heated?

• The air over the heated rod travelled to the other rod and made it warm.

• Part of the heat was converted to radiation causing particles to float over to the cooler rod.

• Electrons within the rods started travelling, distributing heat consistently in both rods.

• The particle vibrations in the first rod transferred energy by conduction to the particles in the second rod.

Multiple Choice

The diagram above shows a Bunsen burner heating a beaker of water on a beaker stand. The arrows represent the transfer of heat energy in the water. Which process is primarily responsible for the transfer of heat in the beaker as indicated by the arrows in the diagram?

• conduction

• radiation

• convection

• condensation

Multiple Choice

Read the following passage and determine which process it is describing:  The air molecules around a candle flame are excited by the increased energy and spread out, decreasing in density and rising above the cooler, denser air around it. The denser air fills the space of the lighter air, continuing the cycle.

• conduction

• convection

• radiation

• sublimation

Multiple Choice

Heat always moves

• in convection currents

• by radiation

• from hot to cold

• from cold to hot

Multiple Choice

Matter in which atoms vibrate so much that they are far apart.

• liquid

• solid

• gas

• thermal energy

Multiple Choice

Which of the following pictures represents particles in a solid?

• None of the options represent particle in a dolid.

Multiple Choice

The molecules of which of the following would have the most kinetic energy?

• an ice cube

• a glass of cold water

• boiling water

• a cup of warm tea

Multiple Choice

In heat transfer, heat always flows from the _______________ substance to the _______________ substance.

• hotter to colder

• colder to hotter

• hotter to hotter

• colder to colder

Multiple Choice

What is something that readily conducts heat, electricity, sound...

• insulator

• conduction

• thermal equilibrium

• conductor