Chapter 16 Conduction

When air rapidly expands, its temperature normally _________.

decreases

What would be the consequence of completely eliminating the greenhouse effect?

The average temperature on the surface of Earth would drop to -18°C.

Why is one able to walk on red-hot coals without getting one's feet burned?

The coals are not good conductors of heat.

How would you walk on red-hot coals without getting your feet burned?

Walk fast.

Calculate the quantity of heat absorbed by 80 g of water that warms from 30∘C to 90∘C.

4800 cal

In what form does radiant energy travel?

As electromagnetic waves

Which will normally warm faster: a black pot of cold water or a silvered pot of cold water? Which will cool faster?

Black, black

What is the role of "loose" electrons in heat conductors?

Free electrons can move through a material carrying heat, jostling atoms and other electrons.

When an air molecule is hit by an approaching, faster moving molecule, does the approaching molecule's rebound speed increase or decrease? How about when it hits a receding molecule?

Increase, decrease

Does a good insulator prevent heat from escaping or slow its passage?

Insulators slow the passage of heat

Which of the following would best describe the conductive properties of wood?

It is a good insulator.

Why does the direction of coastal winds change from day to night?

The specific heat of water is greater than the specific heat of land. Water cools more slowly at night. The temperature difference drives convection and offshore winds.

A thermos bottle controls heat transfer by _________.

conduction, convection, and radiation.

What type of gas absorbs and re-emits infrared radiation?

greenhouse gases

Part complete Ceiling fans can make you feel cooler in a warm room. Do ceiling fans reduce room temperature?

no

Distinguish between weather and climate

Climate is what you expect, whereas weather is what you get

What happens to the conductive properties of wood when it gets very hot?

It will continue to remain a good insulator.

If you touch the metal sides in an oven with your bare hand, you're in trouble. But hold your hand briefly in the oven air and you're okay. What does this tell you about the relative conductivities of metal and air?

Metal is a good conductor of heat, whereas air is a terrible conductor of heat.

Since all objects emit energy to their surroundings, why don't the temperatures of all objects continuously decrease?

Objects that are good emitters are equally good absorbers, so they absorb radiation as well as emit it.

Relatively speaking, do high-frequency waves have long wavelengths or short wavelengths? Name an electromagnetic wave with higher frequency than blue light.

Short, ultraviolet

How would decreasing the percentage of greenhouse gases affect the amount of infrared radiation reflected by the atmosphere back toward Earth?

The amount of infrared radiation would decrease.

How would increasing the density of air in the atmosphere affect the amount of infrared radiation returned by the atmosphere back toward Earth?

The amount of infrared radiation would increase

Which of the following most prevents the escape of terrestrial radiation?

Water vapor

If you are able to grab a hot pan and pull it out by the handle without burning yourself, what kind of handle must the pan have, and why?

a wooden handle, because it is the better insulator

Newton's law of cooling applies to objects that undergo _________.

cooling or warming