a physical quantity that follows precise natural laws.

一種嚴格遵循自然法則的物理量

Our universe has a finite amount of it;

在宇宙中能量是有限的

it's neither created nor destroyed

它不是被創造的，也不會被毀滅

but can take different forms,

但能以不同型態存在

such as kinetic or potential energy,

如動能或位能

with different properties and formulas to remember.

它們有不同的性質及公式要記

For instance,

例如 :

an LED desk lamp's 6 Watt bulb

一個 LED 檯燈的 6 瓦燈泡

transfers 6 Joules of light energy per second.

傳送每秒 6 焦耳的光能

But let's jump back up into space

先讓我們跳到太空去看看

to look at our planet, its systems, and their energy flow.

我們的行星、它的系統 以及它能量的流動

Earth's physical systems include

地球的物理系統包含

the atmosphere,

大氣層

hydrosphere,

水圈

lithosphere,

岩石圈

and biosphere.

及生物圈

Energy moves in and out of these systems,

能量在這些系統內外移動

and during any energy transfer between them,

而在任何能量傳遞過程中

some is lost to the surroundings,

一些散失到周圍環境

as heat, light, sound, vibration, or movement.

如熱、光、聲、振動、或移動

Our planet's energy comes from

我們星球的能量取自於

internal and external sources;

地球內部和外部

geothermal energy from radioactive isotopes

來自放射性同位素的地熱能

and rotational energy from the spinning of the Earth

與透過地球旋轉產生的旋轉能

are internal sources of energy,

這兩個屬於內部能量來源

while the Sun is the major external source,

而太陽是主要的外部能源

driving certain systems,

驅動著一些像

like our weather and climate.

天氣與氣候的系統

Sunlight warms the surface and atmosphere

陽光以不同的程度

in varying amounts,

溫暖了地表與大氣

and this causes convection,

而引起對流、

producing winds and influencing ocean currents.

製造風，以及影響洋流

Infrared radiation, radiating out

紅外線輻射，四射到

from the warmed surface of the Earth,

溫暖的地球表面

gets trapped by greenhouse gases

又被溫室氣體罩住

and further affects the energy flow.

進一步影響能量流

The Sun is also the major source of energy

太陽對於生物也是

for organisms.

主要的能量來源

Plants, algae, and cyanobacteria

植物，藻類和藍藻

use sunlight to produce organic matter

利用太陽光將二氧化碳與水

from carbon dioxide and water,

製造出有機物質

powering the biosphere's food chains.

開啟了生物圈的食物鏈

We release this food energy

我們利用像是氧化和

using chemical reactions,

呼吸作用的化學反應

like combustion and respiration.

來釋放食物能

At each level in a food chain,

在每一個食物鏈的階層

some energy is stored

有些能量在剛形成的

in newly made chemical structures,

化學結構下被貯存起來

but most is lost to the surroundings,

但大部分散失到環境中

as heat, like your body heat,

像是熱量，透過食物的消化

released by your digestion of food.

身體散發的熱量被釋放

Now, as plants are eaten by primary consumers,

而植物是由初級消費者食用

only about 10% of their total energy

大約只有原獲得能量的百分之十

is passed on to the next level.

會轉移給下一個營養階層

Since energy can only flow in one direction

又因能量在食物鏈只能

in a food chain,

以同一方向流動

from producers onto consumers and decomposers,

從生產者到消費者和分解者

an organism that eats lower on the food chain,

在食物鏈中食用較自己低層的生物

is more efficient than one higher up.

得到的能量會比吃高層的還高

So eating producers is the most efficient level

所以食用生產者是最有效的

at which an animal can get its energy,

一隻動物可以藉此得到能量

but without continual input of energy

若持續缺乏了輸入

to those producers,

給生產者的能量

mostly from sunlight,

大部分是來自太陽光

life on Earth as we know it

我們所知在地球上的生物

would cease to exist.

將不復存在

We humans, of course, spend our energy

我們人類，除了吃，當然

doing a lot of things besides eating.

消耗精力去做很多事情

We travel, we build, we power all sorts of technology.

我們旅行、我們建設 我們供電給各種科技

To do all this,

要做到這一切

we use sources like fossil fuels:

必須使用像是化石燃料的來源：

coal, oil, and natural gas,

煤、石油和天然氣

which contain energy

其中含有的能量

that plants captured from sunlight

是植物長年從太陽光

long ago

所吸取的能量

and stored in the form of carbon.

並以碳的形式貯存

When we burn fossil fuels in power plants,

當化石燃料在發電廠燃燒時

we release this stored energy

它所儲存的能量會釋放

to generate electricity.

我們而用此來發電

To generate electricity,

為了發電

heat from burning fossil fuels

燃燒化石燃料產生的熱能

is used to power turbines

提供渦輪機動力

that rotate magnets,

旋轉磁鐵

which, in turn, create magnetic field changes

而此，進而使磁場改變

relative to a coil of wire,

造成線圈產生相對運動

causing electrons to be induced to flow in the wire.

電子因此感應流動於線圈中

Modern civilization depends on our ability

現代文明仰賴我們

to keep powering that flow of electrons.

電量持續的供給

Fortunately, we aren't limited

幸運的是，我們沒有限制說

to burning non-renewable fossil fuels

一定要燃燒不可再生的

to generate electricity.

化石燃料來發電

Electrons can also be induced to flow

電子也能藉由與光子的直接互動

by direct interaction with light particles,

感應流動而發電

which is how a solar cell operates.

這就是太陽能電池的運作方式

Other renewable energy sources,

其他可再生能源

such as wind, water, geothermal, and biofuels

例如風、水、地熱、及生物燃料

can also be used to generate electricity.

都可以拿來發電

Global demand for energy is increasing,

全球能源需求在不斷增加

but the planet has limited energy resources

但地球上能使用的能源有限

to access through a complex energy infrastructure.

要透過複雜的能源基礎建設才能用到

As populations rise,

隨著人口逐增

alongside rates of industrialization and development,

以及工業化和發展的速度

our energy decisions grow more and more important.

我們對能源的決策也越來越重視

Access to energy

能源利用的影響攸關

impacts health, education, political power, and socioeconomic status.

健康、教育、政治權力和社會經濟地位

If we improve our energy efficiency,

如果我們改善使用能源的效率

we can use our natural resources more responsibly

我們更能善待自然資源

and improve quality of life for everyone.

並提升每個人的生活品質