Review: Heat Flow

insulation

any material that reduces heat flow

convection

heat flow due to the mass motion of a fluid

A material with a ______ R-value is a better insulator.

higher

A catalytic combustor _________ the efficiency of a fireplace.

increases

The Sun's energy reaches the earth by . . .

radiation

The speed of molecules is indirectly related to a measurement called . . .

temperature

What will happen as an object receives energy due to heat flow?

the molecules will move faster

Which of the following reduces energy loss due to conduction, convection, & radiation? - thermos bottle - fiberglass insulation - plastic handle on a cooking pot - foam insulation

thermos bottle

Air spaces are used in insulation because _____.

Air is a poor conductor

2 rooms are in contact. One is at 15*C & the other at 21*C. Choose the best concerning heat flow: - Heat will flow from the 21*C room to the 15*C room - Heat will flow from the 15*C room to the 21*C room - There will be no exchange of heat - Heat will flow both ways in equal amounts

Heat will flow from the 21*C room to the 15*C room

Which of the following situations would result from water having a high specific heat? - When cooking pasta, the water boils really fast. - The ocean changes temperatures quickly as the seasons change. - It doesn't take more than a day or 2 in the summertime for the swimming pool to heat up to a comfortable temperature. - Sweat evaporating from the skin cools the body because so much heat is removed while it evaporates.

Sweat evaporating from the skin cools the body because so much heat is removed while it evaporates

The element in a thermostat that is sensitive to temperature changes is _____. - mercury - a battery - alcohol - a bimetallic strip

a bimetallic strip

Compressor

a pump that increases the pressure of a gas

example of conduction: - a spoon resting in a cup of tea gets hot - water warming on a stove - the Sun warming the Earth

a spoon resting in a cup of tea gets hot

R-value

a standardized measure of the ability to insulate

SELECT ALL THAT APPLY which of the following can supply the energy for modern home heating systems? - electricity - biomass - solar - geothermal

all of them

Why is thermal energy produced not generally usable to do work?

because the thermal energy dissipates too quickly & is not concentrated enough to be used

Until the late 1800's, which of the following sources was used to heat most homes? - fossil fuels - electricity - biomass - solar energy

biomass

SELECT ALL THE APPLY A ____ heats water for water-based radiant heat. - fireplace - boiler - furnace - solar collector

boiler , solar collector

Which of the following is an example of an internal combustion engine? - cannon - steam boat - steam locomotive - catapult

cannon

The total amount of energy in the universe is . . .

constant

In the 4-stroke internal combustion engine, hot vapors are expelled during the _____ stroke. - compression - power - intake - exhaust

exhaust

In a refrigerator or cooling system, an _______ controls the flow of fluid from a high pressure area to a low pressure area. - compressor - thermostat - bimetallic strip - expansion valve

expansion valve

A steam boat is an example of a machine that uses an _______ combustion engine

external

A piece of wood & a piece of steel are at the same temperature; however, the steel feels hotter. This is because the steel has . . .

greater thermal conductivity

Gases, fluids, and other solids in contact with a moving object will produce ______ due to friction.

heat flow

Radiation

heat flow away from the emitting object by means of electromagnetic waves, mostly in the infrared region

A ______ fireplace continues to radiate even after the fire is extinguished.

masonry

thermal equilibrium

materials in contact are at the same temperature

entropy

measure of disorder

One of the fundamental principles used in an internal combustion engine is that hot gases occupy _______ space than cool gases or liquids.

more

If the internal energy of a system increases but there is no change in temp., then the system's _______ energy is increasing.

potential

Fuel is combusted in the ________ stroke of a 4-stroke engine. - intake - compression - power - exhaust

power

In the 4-stroke internal combustion engine, fuel is ignited during the ______ stroke. - compression - power - intake - exhaust

power

During the refrigeration cycle, warm gases are made even hotter due to . . . - pressurization - expansion - friction - evaporation

pressurization

The component of a refrigerator pr air conditioner that absorbs & releases heat energy is the ______.

refrigerant

What is the most commonly used method of food preservation today? - refrigeration - drying foods - smoking raw meats - salt curing

refrigeration

The _______ law of thermodynamics states that the tendency of the universe is to increase entropy.

second

The _______ law of thermodynamics states that when 2 objects of different temperature are in contact, heat energy will flow from the hotter to the cooler object.

second

The thermodynamic law that explains the movement of heat energy during the refrigeration cycle is the _______.

second

Newly designed home refrigerators use _____ as a refrigerant.

tetrafluoroethane

example of radiation: - a spoon resting in a cup of tea gets hot - water warming on a stove - the Sun warming the Earth

the Sun warming the Earth

specific heat capacity

the quantity of energy that must be absorbed to raise the temperature of a material 1*C

If 2 different substances, with the same mass absorb the same amount of energy, which of the following can be predicted? - the temp. of the substance with the higher specific heat will increase more than the one with a lower specific heat - the temp. of the substance with the lower specific heat will increase more than the one with a higher specific heat

the temp. of the substance with the lower specific heat will increase more than the one with a higher specific heat

internal energy

total kinetic & potential energy of the molecules in an object

The main reason ice blocks became unpopular for cooling food was _____.

unsanitary sources of ice

In the process of cooling air inside the refrigerator, the refrigerant . . . - freezes - cools - vaporizes - melts

vaporizes

example of convection: - a spoon resting in a cup of tea gets hot - water warming on a stove - the Sun warming the Earth

water warming on a stove