Chapter 2: Energy

Question 1

Define ‘Albedo’.

Answer 1

The reflectivity of the surface of a planet.

Question 2

Define ‘Blackbody radiator’.

Answer 2

A (hypothetical) perfect radiator of light that absorbs all light that strikes it and reflects none; its light output depends only on its temperature.

Question 3

Define ‘Celsius temperature scale’.

Answer 3

The temperature scale in which the zero reference point is the freezing temperature of water at surface atmospheric pressure and the boiling point of water is assigned a temperature of 100 degrees Celsius.

Question 4

Define ‘Conduction’.

Answer 4

The means by which heat is transmitted through solids without deforming the solids. Moves from one object to an adjacent object through the transfer of kinetic energy.

Question 5

Define ‘Convection’.

Answer 5

The process by which hot, less dense materials rise upwards, being replaced by cold, dense, downward flowing material to create a convection current.

Question 6

Define ‘Degradation (of energy)’.

Answer 6

The transformation of energy into a form that is less useful, or less available for work.

Question 7

Define ‘Electromagnetic radiation’.

Answer 7

A self-propagating electric and magnetic wave, such as light, radio, UV, or infrared radiation; all types travel at the same speed and differ in wavelength or frequency, which relates to the energy.

Question 8

Define ‘Energy’. How can it be added/removed from a system?

Answer 8

The capacity to do work. It can be added/removed typically by work done to or by the system, or by heat flow.

Question 9

Define ‘Energy cycle’.

Answer 9

The flow of energy from the external and internal sources of the planet, that drives the cycles of the Earth system.

Question 10

Define ‘Entropy’.

Answer 10

A measure of disorganization. Entropy increases as the usefulness/ability to do work decreases. Absolute zero K would hypothetically result in zero entropy.

Question 11

Define ‘Fission’.

Answer 11

Controlled radioactive transformation.

Question 12

Define ‘Fusion (of nuclei)’.

Answer 12

The merging of the nuclei of lightweight chemical elements, particularly H, to form heavier elements such as He and C.

Question 13

Define ‘Geothermal gradient’.

Answer 13

The rate of increase of temperature downward in the Earth. It varies from site to site and is less pronounced under the continents than under ocean basics, where the crust is thinner.

Question 14

Define ‘Gradients’.

Answer 14

A measure of the vertical drop over a given horizontal distance. (Definition in back of book, perhaps not appropriate to chapter)
Alternatively, the flow of something down a gradient from higher concentration to low.

Question 15

Define ‘Gravity’.

Answer 15

The mutual physical attraction between any two masses, such as Earth and the Moon.

Question 16

Define ‘Greenhouse effect’.

Answer 16

The property of the Earth’s atmosphere by which long wavelength heat rays from the Earth’s surface are trapped or reflected back by the atmosphere.

Question 17

Define ‘Heat’.

Answer 17

Al so known as thermal energy. The energy of a body due to the motions of its atoms. Temperature is the measure of that motion.

Question 18

Define ‘Kelvin temperature scale’.

Answer 18

The absolute temperature scale in which the foundation is the point where entropy is zero.

Question 19

Define ‘Kinetic energy’.

Answer 19

Energy that is expressed in the movement of matter.

Question 20

Define ‘Luminosity’.

Answer 20

The total amount of energy radiated outward each second by the Sun or any other star.

Question 21

Define ‘Potential energy’.

Answer 21

The energy stored in a system.

Question 22

Define ‘Power’.

Answer 22

The amount of work done per unit time.

Question 23

Define ‘Radiation’.

Answer 23

Transmission of heat energy through the passage of electromagnetic waves.

Question 24

Define ‘Radiatively active gas’.

Answer 24

Gases in the lower part of the atmosphere that absorb outgoing radiation, thus preventing the radiactive loss of heat.

Question 25

Define ‘Radiogenic heat’.

Answer 25

Heat energy produced by the spontaneous breakdown, or decay, of radioactive elements.

Question 26

Define ‘Reflection’.

Answer 26

The bouncing of a wave off the surface between two media.

Question 27

Define ‘Spectrum’.

Answer 27

A group of electromagnetic rays arranged in order of increasing or decreasing wavelength.

Question 28

Define ‘Star’.

Answer 28

A large spherical mass of ionized gas that radiates heat as a result of thermonuclear reactions in its core.

Question 29

Define ‘Stratospheric ozone layer’.

Answer 29

The region of the stratosphere within which ozone (O3) absorbs radiation in the short-wavelength region of the electromagnetic radiation spectrum.

Question 30

Define ‘Temperature’.

Answer 30

A measure of the average kinetic energy of all the atoms in a body. A measure of heat/thermal energy.

Question 31

Define ‘Terrestrial energy’.

Answer 31

Also known as Geothermal energy, it is heat energy drawn from the Earth’s internal heat.

Question 32

Define ‘Tide’.

Answer 32

The twice-daily rise and fall of the ocean surface resulting from the gravitation attraction of the Moon and Sun.

Question 33

Define ‘Work’.

Answer 33

The addition or subtraction to the internal energy of a system.

Question 34

Define ‘Thermodynamics’. What are the three laws?

Answer 34

The set of natural laws that govern the transfer of energy from one body to another.

1. In a system of constant mass, the energy involved in any physical or chemical change is neither created nor destroyed, but merely changed from one form to another.
2. Energy always changes from a more useful, more concentrated for to a less useful, less concentrated form.
3. Postulates the existence of the state of absolute zero, in which all molecular motion would cease and entropy would disappear.

Question 35

What are some forms of energy?

Answer 35

Thermal, chemical, nuclear, mechanical, gravitational, radiant or electromagnetic, electrical, sound, and motion.

Question 36

What are the three fundamental mechanisms of heat transfer?

Answer 36

Conduction, convection, and radiation.

Question 37

The Sun is a star, in which nucleosynthesis occurs by fusion. The Sun produces most of its energy by thermo- nuclear reactions in which hydrogen protons fuse to form helium. During the fusion process, some mass is converted to energy. Each individual fusion reaction produces only a tiny amount of energy, but such an enormous amount of hydrogen fuel is continuously converted to helium that the Sun’s overall luminosity is huge. Only a tiny fraction of the total energy emitted by the Sun reaches Earth; even so, a __ percent increase or decrease would have a significant impact on climate.

Answer 37

1 %. In text says 1 K.

Question 38

What are the equations used to describe light and what are the types of radiation in the electromagnetic spectrum?

Answer 38

c=(frequency)(gamma) and E=h(frequency)

Radio->Infrared->Visible->UV->X-ray->Gamma

Question 39

What are the six layers of the Sun?

Answer 39

The Sun has six concentric layers: the core, in which the nuclear fusion reactions occur; the radiative layer, across which energy from the core moves by radiation; the convective layer, across which energy moves by convection; the photosphere, an intensely turbulent zone which emits the light that reaches Earth; the chromosphere, a transparent, low-density layer of very hot gas; and the corona, a zone of even lower density gas than the chromosphere.

Question 40

The Sun’s spectral curve matches that of a blackbody radiator emitting at __, the average temperature of the photosphere. The peak is at a wavelength of __, in the visible part of the electromagnetic spectrum. Gases in Earth’s atmosphere selectively absorb some wavelengths from the solar radiation as it passes through on its way to the surface. Notably, ozone absorbs radiation in the very short- wavelength, ultraviolet portions of the spectrum.

Answer 40

5800 K

5x10^-7 m

Question 41

What is the temperature of Earth’s core?

Answer 41

~5000 degrees Celsius.

Question 42

Heat flow from the interior to the surface is greatest in locations with volcanic activity. Heat reaches the bottom of the lithosphere primarily by ___, and passes through the lithosphere primarily by __. Slow convection currents of solid rock deep in Earth’s interior provide the driving force behind plate tectonics, in addition to generating volcanic eruptions.

Answer 42

convection

conduction

Question 43

What are some of the sources of Earth’s internal energy?

Answer 43

Radiogenic heat from the spontaneous decay of naturally occurring radioactive elements; accretionary heat from the collision and accretion of particles during the formation of Earth; tidal heat generated by the distortions of body tides; and gravitational and latent heat of crystallization associated with core formation.

Question 44

The total amount of energy flowing into Earth’s energy budget is more than 174,000 terawatts (or 174,000 1012 watts). Solar radiation dominates the flow of energy into Earth’s energy budget, at __ percent of the total. The second most powerful source, at 23 terawatts or ___ percent of the total, is Earth’s internal heat energy. Tidal energy accounts for approximately 3 terawatts, or ___ percent of the total.

Answer 44

99. 985 %
100. 013 %
101. 002 %

Question 45

About ___ percent of incoming solar radiation is reflected back to space as a result of the planet’s albedo.

Answer 45

40 %

Question 46

Earth, a lower-temperature radiator than the Sun, has a peak at a wavelength of ___, in the infrared part of the electromagnetic spectrum. Earth’s outgoing radiation is selectively absorbed by radiatively active gases, notably water vapor and carbon dioxide. This causes the greenhouse effect, in which some outgoing radiation from the thermal portion of the spectrum is retained near the surface, forming a “blanketing” layer of warmed air.

Answer 46

1x10^-5 m

Question 47

What are some energy sources used by humans and where do they come from?

Answer 47

Fossil fuels, by far the main source of energy for modern industrial society, come from the ancient remains of plants and animals; they are an expression of stored solar energy. Wind energy, wave energy, and biomass energy are also secondary expressions of solar radiation. Geothermal energy comes from Earth’s internal heat sources. Tidal and hydroelectric energy come from the kinetic energy of water. Nuclear energy is produced by controlled fission of radioactive isotopes.