Heat Transfer Quiz

What are convection currents and what causes them?

A convection current is the flow that transfers heat within a fluid. It is caused by the heating and cooling of the fluid which changes the density as molecules expand and compact.

What causes convection currents in Earth's mantle?

Convection currents in Earth's mantle are caused by the heat in the core and mantle which changes the fluid's density.

Radiation

The transfer of heat through empty space.

Heat transfer

The movement of energy from a warmer object to a cooler object.

Conduction

Heat transfer by direct contact particles of matter.

Convection

The transfer of heat by the movement of a heated fluid in currents.

Density

Measures how much mass there is in a volume of a substance.

Heat travels from.....

Hot to cold

Examples of radiation:

The sun warms the earth, candle warms a face, fire warms a marshmallow.

Thermal energy

The total energy if the particles in a substance.

What is true about thermal energy?

Dependent on the temperature of the substance, partly depends on how the particles of a substance are arranged, partly depends on the number of particles of the substance.

What is a substance's specific heat?

The amount of heat required to raise the temperature of 1 kilogram of a substance by 1 kelvin.

What is the unit of measure for specific heat?

Joules per kilogram- kelvin or J/ (kg x k)

What does it mean if a material has a high specific heat?

The material can absorb a great deal of thermal energy without a great change in temperature.

What does it mean if a material has a low specific heat?

The material's temperature will change quickly with little thermal energy.

Energy gained or lost by an object is related to what factors?

Mass, specific heat, change in temperature

What is the formula you can use to calculate thermal energy changes?

Change in energy= Mass x specific heat x change in temperature

An entire lake is heated by water from a hot spring at the bottom of the lake.

Convection

Sunlight melts a wax crayon left outside.

Radiation

A burner on a stove heats the bottom of a pot.

Conduction

You feel the warm glow of a bonfire.

Radiation

When heat flows from one substance to another, what happens to the temperature of the substance giving off the heat and the temperature of the substance absorbing the heat?

The substance giving off the heat energy will decrease in temperature while the substance that is absorbing the heat energy will increase in temperature. This heat transfer occurs until both materials are about the same temperature.

Why can't ice transfer coldness into another substance?

There is no such thing as coldness because it is the lack of heat energy. Instead, the ice gets warmer as the thermal energy of a warmer object flows into it.

Conductor

A material that conducts heat well.

Insulator

A material that does not conduct heat well.

Examples of conductors:

Silver, fiberglass, tile

Examples of insulators:

Air, wood, wool