Chapter 16

How do "loose" electrons affect heat conduction?

Free electrons can move through a material jostling (bumping or pushing) atoms and other electrons.

What makes materials such as wood, fur, feathers, and even snow, good insulators?

Outer electrons in these materials are firmly attached

When your foot stands on a tile floor, thermal energy always flows ____

from either your foot or the tile, depending on the temperature of the tile

Thermal conduction mostly involves the motion of _____

electrons

Thermal convection applies mainly to _________.

fluids

When air rapidly expands, its temperature normally ____

Decrease

What happens to the volume of air as it rises? What happens to its temperature?

Volume increases; temperature decreases.

Determine the amount of heat required to increase the temperature of 60 g of water from 0 C to 100 C. The specific heat capacity for water is 1 cal / (g x C)

(60×100) = 6000 cal

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

(90-30) * 30 = 1800 cal

Heat travels from the Sun to Earth by the process of ____

Radiation

In what form does radiant energy travel?

As electromagnetic waves

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

Short, ultraviolet

 

Cite a primary difference between waves of solar radiation and waves of terrestrial radiation.

Solar radiation peaks at shorter wavelengths in the visible, whereas terrestrial radiation peaks at longer wavelengths in the infrared.

Because 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.

What determines whether an object is a net absorber or a net emitter of radiant energy at a given time?

It is determined by the temperature of the object relative to its surroundings. Hotter objects are net emitters.

Can an object be both a good absorber and a good reflector at the same time?

No. A good absorber reflects very little light.

Why does the pupil of your eye appear black?

Light that enters the pupil bounces several times before exiting, and is absorbed on each bounce, so little light exits.

What happens to the temperature of something that radiates energy without absorbing the same amount in return?

It cools

Our atmosphere is transparent to solar radiation, but it traps the energy that causes the Greenhouse Effect. Why?

Because the solar energy absorbed by Earth is reradiated as longer-wavelength radiation

How does glass act like a one-way valve for a conventional greenhouse? Does the atmosphere similarly act as a one-way valve?

Glass transmits solar radiation into the greenhouse and blocks infrared radiation from leaving the greenhouse. The same thing happens in the atmosphere.