十万个为什么·科学启蒙30篇（2）

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为什么口香糖嚼起来有弹性，不像糖果那样溶解？

Chewing gum stays chewy because its base is made from synthetic or natural polymers that resist saliva.
Unlike sugar or chocolate, these rubber-like substances don’t break down easily in water or enzymes.
Modern gum uses food-grade elastomers such as styrene-butadiene or polyvinyl acetate.
Sweeteners and flavorings dissolve quickly, but the gum base remains intact during chewing.
Saliva moistens the surface but cannot chemically react with the polymer chains inside.
That’s why swallowed gum passes through your digestive system unchanged, just like fiber.
Heat makes gum softer, while cold makes it stiff—but it never truly melts like ice or butter.
Scientists test new bases to make gum biodegradable without losing its fun, stretchy feel.
Flavor lasts only minutes because volatile oils evaporate or dissolve long before the base does.
You can stretch, blow bubbles, or fold gum because its molecular structure is both elastic and cohesive.