The standard unit for measuring energy, work, and heat in the metric system used by science everywhere — its symbol is a capital J. One joule is a small amount: roughly the energy it takes to lift a small apple one metre, or to run a one-watt light for one second.

The standard unit for measuring energy, work, and heat in the metric system used by science everywhere在科學界全世界通用的公制系統裡，測量能量、功和熱的標準單位——its symbol is a capital J符號是大寫J。One joule is a small amount一焦耳（joule）是很小的量：roughly the energy it takes to lift a small apple one metre, or to run a one-watt light for one second大約是把一顆小蘋果舉高一公尺，或讓一瓦的燈亮一秒鐘所需要的能量。

Because it is so small, real life uses bigger versions — kilojoules (kJ, a thousand) and megajoules (MJ, a million).

Because it is so small因為它太小了，real life uses bigger versions現實生活會用比較大的版本——kilojoules (kJ, a thousand) and megajoules (MJ, a million)千焦耳（kJ，一千焦耳）和百萬焦耳（MJ，一百萬焦耳）。

Students meet it constantly in physics, since work, heat and every kind of energy are all measured in the same unit.

Students meet it constantly in physics學生在物理課裡會不斷遇到它，since work, heat and every kind of energy are all measured in the same unit因為功、熱和各種能量都是用同一個單位測量的。

You also meet it on food packets: outside the United States, nutrition labels give energy in kilojoules, sometimes alongside calories. One food calorie is about 4.2 kilojoules, which is why the kilojoule numbers on a packet look so alarmingly large.

You also meet it on food packets你也會在食品包裝上遇到它：outside the United States, nutrition labels give energy in kilojoules, sometimes alongside calories在美國以外，營養標示會用千焦耳標示能量，有時候會跟卡路里一起標。One food calorie is about 4.2 kilojoules一大卡大約等於4.2千焦耳，which is why the kilojoule numbers on a packet look so alarmingly large這就是為什麼包裝上的千焦耳數字看起來那麼嚇人的原因。

The unit is named after James Prescott Joule, the English scientist who showed that heat and mechanical work are two forms of the same thing.

The unit is named after James Prescott Joule這個單位是以James Prescott Joule命名的，the English scientist who showed that heat and mechanical work are two forms of the same thing他是一位英國科學家，證明了熱和機械功其實是同一件事的兩種形式。