A kind of plastic that goes soft when you heat it and hard again when it cools — and the change can happen again and again. Heat it, shape it, let it cool, and if you are not happy, heat it once more and reshape it.

A kind of plastic一種塑膠 that goes soft when you heat it加熱時會變軟 and hard again when it cools冷卻後又會變硬 — and the change can happen again and again而且這個變化可以一再重複。 Heat it加熱它 shape it塑形 let it cool讓它冷卻 and if you are not happy如果不滿意 heat it once more and reshape it再加熱一次重新塑形。

Most everyday plastics are like this: drink bottles, plastic bags, LEGO bricks, the plastic shell of a phone case, the filament used in 3D printers.

Most everyday plastics are like this大多數日常塑膠都是這樣 drink bottles, plastic bags, LEGO bricks, the plastic shell of a phone case, the filament used in 3D printers像是飲料瓶、塑膠袋、樂高積木、手機殼的塑膠外殼，還有 3D 印表機用的線材。

The word works as both a noun ('nylon is a thermoplastic') and an adjective ('thermoplastic material'). It belongs to factories, materials science, and product design; ordinary people just say 'plastic'.

The word這個字 works as both a noun ('nylon is a thermoplastic')可以當名詞，像「nylon is a thermoplastic」 and an adjective ('thermoplastic material')也可以當形容詞，像「thermoplastic material」。 It它 belongs to factories, materials science, and product design屬於工廠、材料科學和產品設計的用語 ordinary people just say 'plastic'一般人就只說「plastic」。

Its opposite partner is thermosetting plastic, which hardens once and then stays hard forever. This is why thermoplastics are the easy ones to recycle — you can melt them down and make something new — while the setting kind cannot be melted back.

Its opposite partner它的對照組 is thermosetting plastic是熱固性塑膠 which hardens once and then stays hard forever這種塑膠硬化一次之後就永遠是硬的。 This is why這也是為什麼 thermoplastics are the easy ones to recycle熱塑性塑膠比較容易回收 — you can melt them down and make something new因為可以熔化重製成新的東西 — while the setting kind cannot be melted back而熱固性塑膠沒辦法再熔回去。